Utilization of Medical Services for the Treatment of Acute Low Back Pain: Conformance with Clinical Guidelines W. SCOTT SCHROTH, MD, MPH, JOEL M. SCHECTMAN, MD, MPH, ELAINE G. ELINSKY, MSN, JOY C. PANAGIDES, PA, MPH
Objective: To assess the utilization o f diagnostic a n d therapeutic medical services f o r the m a n a g e m e n t o f acute l o w back p a i n in a p r i m a r y care s e t t i n ~ a n d to d e t e r m i n e w h e t h e r such utilization c o n f o r m s to suggested guidelines f o r the m a n a g e m e n t o f this c o n d i t l o m Study design: A retrospective c h a r t a u d i t o f consectaive c a s e s o f acute low back pain~ specific elements o f the diagnostic a n d therapeutic a p p r o a c h were j u d g e d a p p r o p r i a t e o r i n a p p r o p r i a t e b a s e d o n c o m p a r i s o n with p u b l i s h e d reco m m e n d a t i o n s s u p p o r t e d by the medical literature. Setting: The p r i m a r y care adult p r a c t i c e o f a university-aff i l i a t e d health m a i n t e n a n c e o r g a n i z a t i o m Patients: One h w n d r e d eighty-three p a t i e n t s p r e s e n t i n g with acute low back p a i n o f musculoskeietal origin~ Measurements and main results: A c c o r d i n g to s u g g e s t e d guidelines f o r the care o f acute low back p a i n , 26% o f p l a i n l u m b a r x-rays ( 1 0 / 3 8 ) , 66% o f c o m p u t e d t o m o g r a p h y (CT) a n d magnetic r e s o n a n c e i m a g i n g (MRI) s c a n s ( 1 2 / 1 8 ) , a n d 82% ( 2 3 / 2 8 ) o f subspecialty referrals were c a t e g o r i z e d as inappropriate. A m o n g p a t i e n t s w i t h o u t indications f o r these services, 12% ( 1 0 / 8 5 ) h a d received l u m b a r x-rays, 7% ( 1 2 / 1 6 8 ) h a d received l u m b a r MRI o r CTscans, a n d 14 % ( 2 3 / 1 68) h a d received subspecialty referrals. Und e r u t i l t z a t i o n o f these services h a d o c c u r r e d in 71% ( 7 0 / 9 8 ) o f p a t i e n t s with a n i n d i c a t i o n f o r p l a i n l u m b a r radiography, a n d 47% ( 7 / 1 5 ) o f p a t i e n t s with p o t e n t i a l i n d i c a t i o n s f o r surgical r e f e r r a l o r C T / M R l scanning. Neither overutilization n o r u n d e r u t t l i z a t i o n h a d led to adverse outcomes o r delays i n d i a g n o s i s in this small s a m p l e . Conclusions: A c c o r d i n g to guideiines f r o m the medical literature, the p r i m a r y care p h y s i c i a n s i n this study both overutilized a n d u n d e r u t t l i z e d diagnostic a n d r e f e r r a l services i n cases o f acute low back p a i n . I t is necessary to d e t e r m i n e whether u n d e r u t i l i z a t i o n o f p l a i n l u m b a r radio g r a p h y adversely affects diagnostic accuracy a n d w h e t h e r overuttlizatton o f o t h e r services improves import a n t c l i n i c a l o u t c o m e s , g i v e n the generally benign n a t u r a l history o f this c o n d i t i o m Key words: backache; p r i m a r y care; clinical guidelines; utilization4 low back padn~ J GEN I N - t ~ MED 1992;
7:486-491. THE MANAGEMENTOF LOW BACK PAIN, usually a benign and self-limited condition, c o n s u m e s an extraordinary a m o u n t of medical care resources. Estimates of the direct cost of treating patients w h o have b a c k pain range from $8 billion to $13 billion p e r y e a r ) , 2 C o m b i n e d
Received from the Department of Health Care Sciences, George Washington University Medical Center, 2150 Pennsylvania Avenue, NW, Washington, DC 20037. Address correspondence and reprint requests to Dr. Schroth. 486
w i t h the indirect costs of disability related to acute and chronic back pain, total e x p e n d i t u r e s for this condition are c o m p a r a b l e to those for ischemic heart disease. 3 In part, the i m p a c t of l o w b a c k pain is e x p l a i n e d b y the high prevalence of this condition. Nearly 80% of all adults report at least one e p i s o d e of l o w b a c k pain during their lifetimes. The yearly incidence of b a c k pain a p p r o a c h e s 7%, and medical care is sought in 70% of these instances. 2' 4, 5 Most visits for l o w b a c k pain are to p r i m a r y care physicians, making this the second leading reason for physician visits in a m b u l a t o r y m e d i c i n e (an estimated 16 million visits p e r year) .6 In a comparison of the amounts of medical resource utilization for several c o m m o n p r i m a r y care conditions, l o w b a c k pain ranked second only to diabetes mellitus in the f r e q u e n c y w i t h w h i c h diagnostic and t h e r a p e u t i c procedures w e r e utilized on a per-case basis. This is explained by the extensive utilization of radiographic procedures, referrals for physical therapy or manipulation, and p r e s c r i p t i o n medications. 7 Recent advances in understanding the natural history of acute l o w b a c k pain call into question the intensive utilization of medical resources for this condition. It is clear that 90% o f all patients w i t h acute l o w b a c k pain of musculoskeletal origin will have resolution of their s y m p t o m s within six weeks, p r o b a b l y regardless of any specific intervention. Over 50% of those w i t h sciatica or mild n e u r o m o t o r deficits also can b e exp e c t e d to r e c o v e r in this t i m e period, and only 5 - 10% will ever require surgical intervention. 4' s Since a benign diagnosis and rapid clinical recovery are the rule in most cases of acute l o w b a c k pain, f e w diagnostic or t h e r a p e u t i c interventions have b e e n d e m o n s t r a t e d to i m p r o v e patient care o u t c o m e s . This has led to recommendations favoring a conservative a p p r o a c h to the m a n a g e m e n t of this condition.3"5, 9-11 Unfortunately, there are only limited descriptions of the degree to w h i c h these r e c o m m e n d a t i o n s have influenced the routine p r i m a r y care m a n a g e m e n t of acute l o w back pain. This study reports the actual characteristics of the diagnostic and t h e r a p e u t i c a p p r o a c h to acute low b a c k pain in one p r i m a r y care setting. We describe the utilization of medical resources for this condition, and assess the appropriateness of existing practice patterns according to r e c o m m e n d a t i o n s f r o m the medical literature.
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METHODS Study Site The George Washington University Health Plan (GWUHP) is a group-model health maintenance organization (HMO) affiliated with The George Washington University Medical Center (GWUMC). Faculty members of the Department of Health Care Sciences at GWUMC, including over 30 general internists and family practitioners, provide primary medical care to the 35,000 adult members of the GWUHP. The faculty is assisted in the care of their patients by nurse practitioners, physician assistants, and primary care internal medicine residents. At GWUHP the primary care providers control access to all subspecialty care and most diagnostic and therapeutic procedures. The practitioners have no financial or administrative disincentive for subspecialty referral or the use of diagnostic testing. The adult patient population of GWUHP is 56% female, 55% white, and 40% black. Seventy-eight percent of the patients are 1 8 - 4 4 years old, 3% are over 65.
Subjects Patients were identified for the study by a review of diagnostic coding for all ambulatory visits from January 1 to March 30, 1990. The medical records of all patients seen for a primary diagnosis of back pain were reviewed for inclusion in the study. A record was considered eligible for inclusion if the patient had had an acute episode of musculoskeletal low back pain. The following criteria were used to assess eligibility: 1) pain localized to the low back, 2) duration of pain less than six weeks prior to the index visit, and 3) no back pain reported in the three months prior to the index episode. Cases in which a diagnosis other than musculoskeletal low back pain had been made at the index visit were e x c l u d e d from further analysis. Four hundred seven cases were identified. At the time of the study, 86 charts were unavailable for review. Subsequently, a random sample of these charts was reviewed, and no significant difference in clinical characteristics or amounts of resource utilization was found w h e n the random sample was c o m p a r e d with the study sample. One hundred thirty-eight patients were e x c l u d e d based on the above criteria: 42 had not had low back pain, 75 had had pain within three months of the index visit, ten were pediatric patients and 11 had had pain that had nonmusculoskeletal causes. One hundred eighty-three patients met the inclusion criteria and their cases form the basis for this report.
Chart Audit All records w e r e reviewed by one of the authors (JCP) for details of the patient's past history (including previous back pain and cancer), the presenting history
(September/October), 1992
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(including details of possible inciting events, symptoms of sciatica, sensory change, weakness, and bowel and bladder dysfunction), and the physical examination (including neurologic changes). Diagnostic and therapeutic interventions were also identified from the written record. Referrals for subspecialty care and the use of magnetic resonance imaging (MRI) or c o m p u t e d tomography (CT) were identified from both the medical record and an i n d e p e n d e n t review of billing records for the time period. Details of care provided by subspecialists were obtained from their consultation notes in the primary care medical record. The amounts of utilization of all medical services u p to the date of the chart review, August 1990, were included in the audit. A subsequent survey of these patients revealed that 14% had sought care from outside physicians or through the workers' compensation system following the index visit for back pain. Details of resource utilization for these outside encounters are not reported. A sample of charts was reviewed by two individuals, and the interrater reliabilities of all individual audit variables were assessed. Kappa values for the presence of any subjective neurologic symptoms ranged from 0.4 to 1.0, with a mean of 0.875. For the presence of neurologic findings on physical examination, kappa values ranged from 0.64 to 0.88, with a mean of 0.70. Of the key variables concerning resource utilization (x-rays, MRI/CT scanning, referrals), only plain x-rays were identified solely from the chart audit (kappa = 0.90).
Clinical Guidelines No specific clinical guideline for the evaluation or treatment of acute low back pain was in force at GWUHP during the period under study. The following guidelines are taken from exhaustive reviews of the medical and surgical literature regarding acute low back pain prepared by Richard Deyo and colleagues and published in widely circulated internal medicine journals.9, 10 These guidelines are consistent with reco m m e n d e d diagnostic and therapeutic guidelines from other authoritative medical and surgical publications.1 T M Regarding the use of plain lumbar radiography, Deyo 9 suggested that immediate radiography be reserved for patients with the following characteristics: 1) age over 50 years, 2) history of significant trauma, 3) history of malignancy, 4) fever, 5) unexplained weight loss, 6) substance abuse, 7) pending litigation or workers' compensation proceedings, 8) chronic use of corticosteroids, and 9) n e u r o m o t o r deficits. The suggested timing of plain lumbar radiography for those w h o do not get an initial study and fail to improve is between three and six weeks following the initial presentation. Advanced radiographic procedures such as CT and
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Schroth eta/., RESOURCEUSE FOR LOW BACK PAIN
TABLE 1 Characteristics of the Patients at the Index Visit (N = 183) Gender Male Female Age (mean = 40.7 years) >50 years 1
71 (38.8%)
History* Trauma Lifting injury Fever Cancer Prior low back pain
17 (9.3%) 40 (21.9%) 3 ( 1.6%) 3 (1.6%) 102 (55.7%)
Neurologicsymptoms (patient-reported)* Weakness Sensory change Sciatica
3 (1.6%) 24 (13.1%) 39 (21.3%)
Physical examination* Weakness Sensory change Reflexchange
2 (1.1%) 7 (3.8%) 14 (7.7%)
*For these variables,the absenceof specificcomment in the record was treated as a negativeresponse.
MRI should be reserved for patients w h o have potential neurologic e m e r g e n c i e s (cauda equina s y n d r o m e or a high probability of infection or malignancy based on clinical findings) and should b e used p r i o r to considering surgical intervention in a p p r o p r i a t e patients (see b e l o w ) w h o have failed a course of conservative therapy.9, lo Surgical referral is suggested in the following situations: 1) cauda equina syndrome, 2) progressive or severe neurologic deficit, 3) persistent n e u r o m o t o r deficit after four to six w e e k s of conservative therapy, and 4) persistent sciatica, reflex loss, or sensory loss after four to six w e e k s of conservative therapy, w i t h a positive straight leg raise test. 1°
tient had had persistent n e u r o m o t o r deficits following four weeks of conservative therapy, or persistent sciatica, sensory loss, or reflex abnormalities in the prese n c e of a positive straight leg raise test following four w e e k s of conservative therapy. Since malignancy or infection constitutes a serious condition, and no criterion for a " h i g h p r o b a b i l i t y " threshold has b e e n determined, radiographic imaging or subspecialty referral was considered a p p r o p r i a t e at any time in the p r e s e n c e o f a clinical history of prior or active malignancy, w e i g h t loss, or fever. Underutilization of services was considered to be present w h e n a case m e t the criteria for surgical evaluation or MRI/CT scanning and neither service had b e e n provided. Overutilization of medical services was considered to be present w h e n a case did not m e e t the criteria or w h e n referrals/scans had o c c u r r e d prior to the c o m p l e t i o n of a four w e e k course of conservative therapy. No specific guideline exists regarding the use of physical therapy for acute l o w b a c k pain. Physical thera p y is a h e t e r o g e n e o u s p r a c t i c e consisting o f combinations o f ultrasonic massage, transcutaneous electrical nerve stimulation (TENS), diathermy, and various exercise prescriptions. The effectiveness of these interventions, particularly for acute l o w b a c k pain, have not TABLE 2 Utilization of RadiographicProceduresand Results Plain lumbar radiography First visit Results DDD* DJDt Spondylolysis Osteopenia Scoliosis Normal Follow-upvisit Results DDD DJD
Spondylolysis
Criteria f o r A p p r o p r i a t e Utilization
Underutilization of plain l u m b a r x-rays was identified as failure to obtain such x-rays in the care of patients m e e t i n g any of the above criteria or in the care of any other patient with pain persisting longer than three w e e k s from the date o f the index visit. Overutilization was identified in cases w h e r e x-rays had b e e n obtained on the first visit in the care of patients w i t h o u t one of the above indications or those for w h o m x-rays had b e e n obtained prior to the c o m p l e t i o n of a t h r e e - w e e k trial of conservative therapy. No case of cauda equina s y n d r o m e had b e e n identified and o n l y two patients had manifested mild objective n e u r o m o t o r deficits. Therefore, referrals and MRI or CT scans w e r e considered a p p r o p r i a t e w h e n a pa-
Scoliosis Normal Computed tomography scanning First visit Follow-upvisit Results Disc herniation Normal Magnetic resonanceimaging scanning First visit Follow-upvisit Results Disc herniation DJD Congenitalnarrowing * DDD = Degenerativedisc disease. t DJD = Degenerativejoint disease.
2o/183 (i 1.o%) 3 (15.0%)
5 i 2 2
(25.0%) (5.0%) ( i 0.0%) (10.0%)
7 (35.0%) 18/71 (25%) 6 (33.3%)
i (5.6%) i (5.6%) i (s.6%)
9 (50.0%) 0/183 (0.0%) 4/71 (5.6%) 3 (75%)
i (25%)
0/183 (0.0%) 14/71 (19.7%) 12 (86%) I (7.0%) I (7.0%)
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,..JOURNALOFGENERALINTERNALMEDICINE, Volume 7 (September/October), 1992 TABLE 3
Utilization of Medical Servicesfor Acute Low Back Pain According to SuggestedGuidelines(N ~ 183) Overutilization
Underutilization
Service
ServiceNot Expected
ServiceObserved
Rate
ServiceExpected
Lumbar x-ray Magnetic resonanceimaging/ computed tomography Subspecialty referral
85
10
12%
98
168 168
12 23
7% 14%
15*
ServiceNot Observed 70 7*
Rate 71% 47%
*Since the criteria for magnetic resonanceimaging/computed tomographyscanningand subspecialtyreferral were very similar, underutilization was consideredto haveoccurredonly when neither servicehad beenprovided. Among the eight patients with indicationswho had receivedsuch services,six had receivedscans, five had received referrals, and three had received both scans and referrals.
been proven, s, 15.16 Therefore, physical therapy referrals were considered to be of questionable appropriateness when obtained prior to the completion of four weeks of conservative therapy. No criterion for underutilization was considered. For plain x-rays, MRI/CT scans, and subspecialty referrals, comparisons between the observed number and the number expected based on the guidelines were performed with the chi-square test.
RESULTS Characteristics of the Study Population One hundred eighty-three patients presenting with acute low back pain met the inclusion criteria for the study. Table 1 summarizes the demographic characteristics of the patients and the details of the history and physical examination at the time of the index visit. Thirty-nine percent of the patients had made more than one visit for the episode of acute low back pain. The mean number of follow-up visits was 1.5 (range 1 - 6).
Diagnostic Evaluation Table 2 reviews the frequency and results of diagnostic testing in the study sample. Thirty-two percent of all patients ( 5 9 / 1 8 3 ) met one of the suggested criteria for early plain lumbar radiography. Of these patients, 17% ( 1 0 / 5 9 ) had received radiography at the index visit. Lumbar x-rays were subsequently obtained for 46% ( 1 8 / 3 9 ) of the patients with symptoms lasting longer than three weeks. Overall, 71% ( 7 0 / 9 8 ) of the patients meeting guidelines for the use of plain x-rays had not received this test. Twelve percent ( 1 0 / 8 5 ) of the patients who did not meet any guideline criteria had received lumbar x-rays (Table 3). The difference between the total number of x-rays observed (38) and the number expected based on the guidelines (98) was significant (p < 0.0001). T e n percent of the patients had undergone advanced radiographic imaging of the lumbar spine (4 CT s c a n s and 14 MRI scans). Eight of these patients had reported persistent sciatica and one had had asymmetric deep tendon reflexes. No patient undergoing CT or
MRI scanning had had objective findings of weakness or sensory loss. The mean time from the index visit to obtaining these studies was 5.5 weeks. Thirty-three percent ( 6 / 1 8 ) of the scans had been obtained within four weeks of the index visit. Among 12 patients scanned after four weeks of therapy, six had had no neurologic complaint or deficit and no apparent suspicion of malignancy or infection. Two-thirds of all scans ( 1 2 / 1 8 ) were considered inappropriate based on the suggested guidelines. Among the patients not meeting guideline criteria, 7% had received scans (Table 3). The difference between the total number of CT and MRI scans observed (18) and the number expected based on the guidelines (15) was not significant (p > 0.05). Fifteen patients had had persistent sciatica or neurologic changes after four weeks of conservative therapy. Since guidelines for MRI/CT scanning and those for surgical referral are largely the same, underutilization was considered to have occurred when a patient had received neither service. Seven patients had not received either of the services, for an underutilization rate of 47%. The symptoms of all seven patients had subsequently resolved with prolonged conservative therapy. Sixty-seven percent ( 1 2 / 1 8 ) of the studies had been ordered by the primary care physician, and the remainder had been ordered by a subspecialist. Among the patients referred for subspecialty evaluation, 32% ( 9 / 2 8 ) had undergone CT or MRI scanning prior to referral and an additional 25% ( 7 / 2 8 ) had had scans obtained after referral (the timing of the two scans relative to referral could not be determined).
Therapy/Referrals The prescription of nonsteroidal anti-inflammatory drugs was documented in 61% of cases and the prescription of muscle relaxants was documented in 38%. A specific prescription for bedrest was recorded in only 30% of cases, exceeding two days in 70% of these (mean duration 3.7 days). A standard series of prescribed flexion exercises was documented in 32% of cases. Table 4 summarizes the patterns of subspecialty
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Schroth et al.. RESOURCEUSE; FOR LOW BACK PAIN
and physical therapy referral. Immediate referral to orthopedic or neurosurgical subspecialists had occurred in 2% of cases ( 4 / 1 8 3 ) . Only one of these patients had had mild neuromotor deficits. In addition, referral to physical therapy had been made in 7% ( 1 3 / 1 8 3 ) of cases at the time of the index visit. Thirty-four percent ( 2 4 / 7 1 ) of the patients seen more than once had been referred to orthopedics or neurosurgery. Two of the patients had had neuromotor deficits and four others had had persistent sciatica. The mean time from the index visit to the follow-up subspecialty referral was 10.9 weeks (range 2 - 28). Including the four immediate subspecialty referrals, 32% ( 9 / 2 8 ) of the referred patients had been seen by subspecialists within four weeks of the index visit. Among the 19 patients referred after four weeks of conservative therapy, only four met the guideline criteria for surgical referral. Overall, 82% of subspecialty referrals were considered inappropriate. Among the patients not meeting guideline criteria for referral, 14% had received such referrals (Table 3). The difference between the total number of referrals observed (28) and the number expected based on the guidelines (15) was significant (p < 0.001). Review of the subspecialty care provided to all referred patients revealed three cases in which specialized therapy had been provided. One patient had had epidural steroid injection and two had had laminectomies for disc herniation, one with persistent sciatica and one with sciatica and deep tendon reflex loss. The remaining patients had been treated with continued nonsteroidal anti-inflammatory medications and, in some cases, physical therapy referral. Thirty-four percent of the patients seen more than once had been referred to physical therapy. The mean time to referral was 7.3 weeks (range 1 - 36). Including the 13 immediate referrals, 68% of all referrals to physical therapy had occurred less than four weeks from the index visit and were therefore considered of questionable appropriateness. During a mean follow-up period of six months, no patient had been found to have a serious underlying illness.
DISCUSSION This study provides a descriptive evaluation of the medical care and resource utilization for patients with acute low back pain in a primary care setting. The patients evaluated in this study represented a relatively homogeneous group with acute low back pain. The exclusion criteria eliminated patients with chronic back pain and those with frequent relapses. Several cautions should be observed in the interpretation of these data. First, all cases were from the practice of a single urban, university-affiliated HMO. The results may not be representative of practices in other settings or other regions. Second, all data were
TABLE; 4 Utilization of Referral Services
First visit (N = 183) Orthopedics Neurosurgery Physicaltherapy Follow-up visit (N = 71 ) Orthopedics Neurosurgery Physicaltherapy
3 (I .6%) I (0.4%) 13 (7.0%) 13 (I 8.0%) 11 (15.5%) 24 (34.0%)
obtained from retrospective review of medical records. Misclassification bias may have occurred if pertinent findings from the clinical history and examination were absent from the patient's record. Although out-of-plan care had been sought by a few patients in the sample, the setting of a closed-panel HMO permitted nearly complete capture of health care resource utilization for major diagnostic and therapeutic interventions. Finally, the appropriate care of acute low back pain remains controversial, and some readers may therefore disagree with the appropriateness criteria employed in this study. Nonetheless, we believe that the use of explicit and well-documented guidelines was preferable to a more implicit case-by-case, judgment-based method. Plain radiography of the lumbar spine was substantially underutilized relative to suggested guidelines, though a small amount of overutilization was also found. Strict adherence to current recommendations for selective ordering of lumbar radiography would have led to a significant increase in the number of x-rays obtained (from 21% to 54%). These findings are consistent with those of two other studies of plain radiography utilization in the management of low back pain. 17. 18Despite the underutilization of x-rays in these three studies, no adverse effect on diagnostic accuracy or patient outcomes has been detected. Based on the rarity of serious diagnoses for patients with acute low back pain and the poor sensitivity and specificity of lumbar x-rays, the practice of obtaining x-rays routinely for patients with back pain has been discouraged. 3, x9 Although the recommended guidelines for obtaining x-rays have been revised substantially, the results of these three studies suggest that such guidelines might be narrowed further. Nevertheless, it should be noted with caution that none of these studies has had adequate statistical power to determine reliably the effect of underutilization on rare yet serious causes of acute low back pain. Advanced radiographic procedures (CT and MRI scans) were overutilized according to the guidelines. It is interesting that most of the CT and MRI scans had been ordered by the primary care physician, frequently prior to subspecialty referral. We had postulated that early subspecialty referral might lead to excessive utilization of expensive diagnostic technology by the sub-
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specialist; however, most of the excessive utilization in this setting was driven by the primary care physician. Although the judicious use of advanced imaging procedures by the primary care physician may save an unnecessary referral, this evidence suggests that more appropriate referral patterns alone will not substantially improve the p r o p e r use of these technologies, and that emphasis on altering the behavior of primary care physicians may be necessary. Referrals were underutilized in the care of several patients with persistent neurologic complaints w i t h o u t adverse consequences. Again, however, this study lacks p o w e r to evaluate such consequences, and, thus, underutilization must continue to be viewed critically. On the other hand, most referrals were considered inappropriate. Back pain can be a highly distressing symptom to patients, and therefore the " t h e r a p e u t i c " benefit of a second opinion may be important. Nevertheless, for patients unlikely to be considered surgical candidates, the need for a subspecialty opinion seems questionable. Perhaps if the primary care physician presented a more confident and reassuring approach, such referrals could be limited further. Physical therapy referrals had b e e n given in many cases prior to an adequate trial of conservative therapy. Physical therapy lacks evidence of efficacy and generates substantial medical care costs (charge per visit at o u r center is $90, mean n u m b e r of visits is 4). Under these circumstances, physical therapy referrals should probably be reserved for patients w h o have failed less expensive conservative therapies with d o c u m e n t e d efficacy. Appropriate guidelines for the use of physical therapy services for patients w h o do not improve with a trial of conservative therapy must await further studies of the timing and efficacy o f these interventions. This study documents substantial deviation from published clinical guidelines among primary care clinicians during the care of patients w h o have acute low back pain. If such variation stems from a lack of familiarity with suggested guidelines, then explicit dissemination and implementation of these clinical guidelines might lead to more appropriate management of this condition. Alternatively, it is possible that patient demands for reassurance may be driving the utilization of medical resources for this problem, i n d e p e n d e n t of the physician's preferred practice approach. Investigation of this possibility is necessary, since interventions di-
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rected at altering physician behavior alone may have little effect on patient attitudes and demands. Finally, the study of larger and more diverse clinical databases is necessary to determine w h e t h e r adherence to clinical guidelines for acute low back pain improves patient outcomes in a cost-effective manner.
REFERENCES 1. Holbrook TL, Grazier KL, KelseyJL, Stauffer RN. The frequency of occurrence, impact, and cost of musculoskeletal conditions in the United States. Chicago, IL: American Academy of Orthopedic Surgeons, 1984. 2. Deyo RA, Tsui-Wu YJ. Descriptive epidemiology of low-back pain and its related medical care in the United States. Spine. 1987;12:264-8. 3. Liang M, KomaroffAL. Roentgenograms in primary care patients with acute low back pain. Arch Intern Med. 1982; 142:1108-12. 4. Frymoyer JW. Back pain and sciatica. N Engl J Med. 1988; 318:291-300. 5. Nachemson AF. Advances in low-back pain. Clin Orthop. 1985;200:266-78. 6. Cypress BK. Characteristics of physician visits for back symptoms: a national perspective. Am J Public Health. 1983; 73(4):389-95. 7. Lohr KN, Brnok RH, Kamberg CJ, et al. Use of medical care in the Rand Health Insurance Experiment: diagnosis and service-specific analyses in a randomized controlled trial. Med Care. 1986;24 (suppl) :$50-S71. 8. Andersson GJB, Svensson H-O, Oden A. The intensity of work recovery in low back pain. Spine. 1983;8:880-4. 9. Deyo RA. Early diagnostic evaluation of low back pain. J Gen Intern Med. 1986; 1:328-38. 10. Deyo RA, Loeser JD, Bigos SJ. Herniated lumbar intervertebral disk. Ann Intern Med. 1990;112:598-603. 11. Bigos sJ, Battle MC. Acute care to prevent back disability. Clin Orthop. 1987;221:121-30. 12. Spitzer WO (chairman). Scientific approach to the assessment and management of activity related spinal disorders: a monograph for clinicians. Report of the Quebec Task Force on Spinal Disorders. Spine. 1987;12(suppl I):S1-$59. 13. WeinsteinJN, Wiesel SW (eds). The lumbar spine. Philadelphia: W. B. Saunders, 1990. 14. Wiesel SW, Borenstein DG, Low back pain: medical diagnosis and comprehensive management. Philadelphia: W. B. Saunders, 1989. 15. Deyo RA. Conservative therapy for low back pain. JAMA. 1983;250:1057-62. 16. Jackson CP, Brown MD. Analysis of current approaches and a practical guide to prescription of exercise. Clin Orthop. 1983;179;46-54. 17. Deyo RA, Diehl AK. Lumbar spine films in primary care: current use and effects of selective ordering criteria. J Gen Intern Med. 1986;1:20-5. 18. Frazier LM, Carey TS, Lyles MF, Khayrallah MA, McGaghie WC. Selective criteria may increase lumbosacral spine roentgenogram use in acute low-back pain. Arch Intern Med. 1989; 149:47-50. 19. Butt WP. Radiology for back pain. Clin Radiol. 1989;40:6-10.
Objective: To assess the utilization o f diagnostic a n d therapeutic medical services f o r the m a n a g e m e n t o f acute l o w back p a i n in a p r i m a r y care s e t t i n ~ a n d to d e t e r m i n e w h e t h e r such utilization c o n f o r m s to suggested guidelines f o r the m a n a g e m e n t o f this c o n d i t l o m Study design: A retrospective c h a r t a u d i t o f consectaive c a s e s o f acute low back pain~ specific elements o f the diagnostic a n d therapeutic a p p r o a c h were j u d g e d a p p r o p r i a t e o r i n a p p r o p r i a t e b a s e d o n c o m p a r i s o n with p u b l i s h e d reco m m e n d a t i o n s s u p p o r t e d by the medical literature. Setting: The p r i m a r y care adult p r a c t i c e o f a university-aff i l i a t e d health m a i n t e n a n c e o r g a n i z a t i o m Patients: One h w n d r e d eighty-three p a t i e n t s p r e s e n t i n g with acute low back p a i n o f musculoskeietal origin~ Measurements and main results: A c c o r d i n g to s u g g e s t e d guidelines f o r the care o f acute low back p a i n , 26% o f p l a i n l u m b a r x-rays ( 1 0 / 3 8 ) , 66% o f c o m p u t e d t o m o g r a p h y (CT) a n d magnetic r e s o n a n c e i m a g i n g (MRI) s c a n s ( 1 2 / 1 8 ) , a n d 82% ( 2 3 / 2 8 ) o f subspecialty referrals were c a t e g o r i z e d as inappropriate. A m o n g p a t i e n t s w i t h o u t indications f o r these services, 12% ( 1 0 / 8 5 ) h a d received l u m b a r x-rays, 7% ( 1 2 / 1 6 8 ) h a d received l u m b a r MRI o r CTscans, a n d 14 % ( 2 3 / 1 68) h a d received subspecialty referrals. Und e r u t i l t z a t i o n o f these services h a d o c c u r r e d in 71% ( 7 0 / 9 8 ) o f p a t i e n t s with a n i n d i c a t i o n f o r p l a i n l u m b a r radiography, a n d 47% ( 7 / 1 5 ) o f p a t i e n t s with p o t e n t i a l i n d i c a t i o n s f o r surgical r e f e r r a l o r C T / M R l scanning. Neither overutilization n o r u n d e r u t t l i z a t i o n h a d led to adverse outcomes o r delays i n d i a g n o s i s in this small s a m p l e . Conclusions: A c c o r d i n g to guideiines f r o m the medical literature, the p r i m a r y care p h y s i c i a n s i n this study both overutilized a n d u n d e r u t t l i z e d diagnostic a n d r e f e r r a l services i n cases o f acute low back p a i n . I t is necessary to d e t e r m i n e whether u n d e r u t i l i z a t i o n o f p l a i n l u m b a r radio g r a p h y adversely affects diagnostic accuracy a n d w h e t h e r overuttlizatton o f o t h e r services improves import a n t c l i n i c a l o u t c o m e s , g i v e n the generally benign n a t u r a l history o f this c o n d i t i o m Key words: backache; p r i m a r y care; clinical guidelines; utilization4 low back padn~ J GEN I N - t ~ MED 1992;
7:486-491. THE MANAGEMENTOF LOW BACK PAIN, usually a benign and self-limited condition, c o n s u m e s an extraordinary a m o u n t of medical care resources. Estimates of the direct cost of treating patients w h o have b a c k pain range from $8 billion to $13 billion p e r y e a r ) , 2 C o m b i n e d
Received from the Department of Health Care Sciences, George Washington University Medical Center, 2150 Pennsylvania Avenue, NW, Washington, DC 20037. Address correspondence and reprint requests to Dr. Schroth. 486
w i t h the indirect costs of disability related to acute and chronic back pain, total e x p e n d i t u r e s for this condition are c o m p a r a b l e to those for ischemic heart disease. 3 In part, the i m p a c t of l o w b a c k pain is e x p l a i n e d b y the high prevalence of this condition. Nearly 80% of all adults report at least one e p i s o d e of l o w b a c k pain during their lifetimes. The yearly incidence of b a c k pain a p p r o a c h e s 7%, and medical care is sought in 70% of these instances. 2' 4, 5 Most visits for l o w b a c k pain are to p r i m a r y care physicians, making this the second leading reason for physician visits in a m b u l a t o r y m e d i c i n e (an estimated 16 million visits p e r year) .6 In a comparison of the amounts of medical resource utilization for several c o m m o n p r i m a r y care conditions, l o w b a c k pain ranked second only to diabetes mellitus in the f r e q u e n c y w i t h w h i c h diagnostic and t h e r a p e u t i c procedures w e r e utilized on a per-case basis. This is explained by the extensive utilization of radiographic procedures, referrals for physical therapy or manipulation, and p r e s c r i p t i o n medications. 7 Recent advances in understanding the natural history of acute l o w b a c k pain call into question the intensive utilization of medical resources for this condition. It is clear that 90% o f all patients w i t h acute l o w b a c k pain of musculoskeletal origin will have resolution of their s y m p t o m s within six weeks, p r o b a b l y regardless of any specific intervention. Over 50% of those w i t h sciatica or mild n e u r o m o t o r deficits also can b e exp e c t e d to r e c o v e r in this t i m e period, and only 5 - 10% will ever require surgical intervention. 4' s Since a benign diagnosis and rapid clinical recovery are the rule in most cases of acute l o w b a c k pain, f e w diagnostic or t h e r a p e u t i c interventions have b e e n d e m o n s t r a t e d to i m p r o v e patient care o u t c o m e s . This has led to recommendations favoring a conservative a p p r o a c h to the m a n a g e m e n t of this condition.3"5, 9-11 Unfortunately, there are only limited descriptions of the degree to w h i c h these r e c o m m e n d a t i o n s have influenced the routine p r i m a r y care m a n a g e m e n t of acute l o w back pain. This study reports the actual characteristics of the diagnostic and t h e r a p e u t i c a p p r o a c h to acute low b a c k pain in one p r i m a r y care setting. We describe the utilization of medical resources for this condition, and assess the appropriateness of existing practice patterns according to r e c o m m e n d a t i o n s f r o m the medical literature.
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METHODS Study Site The George Washington University Health Plan (GWUHP) is a group-model health maintenance organization (HMO) affiliated with The George Washington University Medical Center (GWUMC). Faculty members of the Department of Health Care Sciences at GWUMC, including over 30 general internists and family practitioners, provide primary medical care to the 35,000 adult members of the GWUHP. The faculty is assisted in the care of their patients by nurse practitioners, physician assistants, and primary care internal medicine residents. At GWUHP the primary care providers control access to all subspecialty care and most diagnostic and therapeutic procedures. The practitioners have no financial or administrative disincentive for subspecialty referral or the use of diagnostic testing. The adult patient population of GWUHP is 56% female, 55% white, and 40% black. Seventy-eight percent of the patients are 1 8 - 4 4 years old, 3% are over 65.
Subjects Patients were identified for the study by a review of diagnostic coding for all ambulatory visits from January 1 to March 30, 1990. The medical records of all patients seen for a primary diagnosis of back pain were reviewed for inclusion in the study. A record was considered eligible for inclusion if the patient had had an acute episode of musculoskeletal low back pain. The following criteria were used to assess eligibility: 1) pain localized to the low back, 2) duration of pain less than six weeks prior to the index visit, and 3) no back pain reported in the three months prior to the index episode. Cases in which a diagnosis other than musculoskeletal low back pain had been made at the index visit were e x c l u d e d from further analysis. Four hundred seven cases were identified. At the time of the study, 86 charts were unavailable for review. Subsequently, a random sample of these charts was reviewed, and no significant difference in clinical characteristics or amounts of resource utilization was found w h e n the random sample was c o m p a r e d with the study sample. One hundred thirty-eight patients were e x c l u d e d based on the above criteria: 42 had not had low back pain, 75 had had pain within three months of the index visit, ten were pediatric patients and 11 had had pain that had nonmusculoskeletal causes. One hundred eighty-three patients met the inclusion criteria and their cases form the basis for this report.
Chart Audit All records w e r e reviewed by one of the authors (JCP) for details of the patient's past history (including previous back pain and cancer), the presenting history
(September/October), 1992
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(including details of possible inciting events, symptoms of sciatica, sensory change, weakness, and bowel and bladder dysfunction), and the physical examination (including neurologic changes). Diagnostic and therapeutic interventions were also identified from the written record. Referrals for subspecialty care and the use of magnetic resonance imaging (MRI) or c o m p u t e d tomography (CT) were identified from both the medical record and an i n d e p e n d e n t review of billing records for the time period. Details of care provided by subspecialists were obtained from their consultation notes in the primary care medical record. The amounts of utilization of all medical services u p to the date of the chart review, August 1990, were included in the audit. A subsequent survey of these patients revealed that 14% had sought care from outside physicians or through the workers' compensation system following the index visit for back pain. Details of resource utilization for these outside encounters are not reported. A sample of charts was reviewed by two individuals, and the interrater reliabilities of all individual audit variables were assessed. Kappa values for the presence of any subjective neurologic symptoms ranged from 0.4 to 1.0, with a mean of 0.875. For the presence of neurologic findings on physical examination, kappa values ranged from 0.64 to 0.88, with a mean of 0.70. Of the key variables concerning resource utilization (x-rays, MRI/CT scanning, referrals), only plain x-rays were identified solely from the chart audit (kappa = 0.90).
Clinical Guidelines No specific clinical guideline for the evaluation or treatment of acute low back pain was in force at GWUHP during the period under study. The following guidelines are taken from exhaustive reviews of the medical and surgical literature regarding acute low back pain prepared by Richard Deyo and colleagues and published in widely circulated internal medicine journals.9, 10 These guidelines are consistent with reco m m e n d e d diagnostic and therapeutic guidelines from other authoritative medical and surgical publications.1 T M Regarding the use of plain lumbar radiography, Deyo 9 suggested that immediate radiography be reserved for patients with the following characteristics: 1) age over 50 years, 2) history of significant trauma, 3) history of malignancy, 4) fever, 5) unexplained weight loss, 6) substance abuse, 7) pending litigation or workers' compensation proceedings, 8) chronic use of corticosteroids, and 9) n e u r o m o t o r deficits. The suggested timing of plain lumbar radiography for those w h o do not get an initial study and fail to improve is between three and six weeks following the initial presentation. Advanced radiographic procedures such as CT and
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Schroth eta/., RESOURCEUSE FOR LOW BACK PAIN
TABLE 1 Characteristics of the Patients at the Index Visit (N = 183) Gender Male Female Age (mean = 40.7 years) >50 years 1
71 (38.8%)
History* Trauma Lifting injury Fever Cancer Prior low back pain
17 (9.3%) 40 (21.9%) 3 ( 1.6%) 3 (1.6%) 102 (55.7%)
Neurologicsymptoms (patient-reported)* Weakness Sensory change Sciatica
3 (1.6%) 24 (13.1%) 39 (21.3%)
Physical examination* Weakness Sensory change Reflexchange
2 (1.1%) 7 (3.8%) 14 (7.7%)
*For these variables,the absenceof specificcomment in the record was treated as a negativeresponse.
MRI should be reserved for patients w h o have potential neurologic e m e r g e n c i e s (cauda equina s y n d r o m e or a high probability of infection or malignancy based on clinical findings) and should b e used p r i o r to considering surgical intervention in a p p r o p r i a t e patients (see b e l o w ) w h o have failed a course of conservative therapy.9, lo Surgical referral is suggested in the following situations: 1) cauda equina syndrome, 2) progressive or severe neurologic deficit, 3) persistent n e u r o m o t o r deficit after four to six w e e k s of conservative therapy, and 4) persistent sciatica, reflex loss, or sensory loss after four to six w e e k s of conservative therapy, w i t h a positive straight leg raise test. 1°
tient had had persistent n e u r o m o t o r deficits following four weeks of conservative therapy, or persistent sciatica, sensory loss, or reflex abnormalities in the prese n c e of a positive straight leg raise test following four w e e k s of conservative therapy. Since malignancy or infection constitutes a serious condition, and no criterion for a " h i g h p r o b a b i l i t y " threshold has b e e n determined, radiographic imaging or subspecialty referral was considered a p p r o p r i a t e at any time in the p r e s e n c e o f a clinical history of prior or active malignancy, w e i g h t loss, or fever. Underutilization of services was considered to be present w h e n a case m e t the criteria for surgical evaluation or MRI/CT scanning and neither service had b e e n provided. Overutilization of medical services was considered to be present w h e n a case did not m e e t the criteria or w h e n referrals/scans had o c c u r r e d prior to the c o m p l e t i o n of a four w e e k course of conservative therapy. No specific guideline exists regarding the use of physical therapy for acute l o w b a c k pain. Physical thera p y is a h e t e r o g e n e o u s p r a c t i c e consisting o f combinations o f ultrasonic massage, transcutaneous electrical nerve stimulation (TENS), diathermy, and various exercise prescriptions. The effectiveness of these interventions, particularly for acute l o w b a c k pain, have not TABLE 2 Utilization of RadiographicProceduresand Results Plain lumbar radiography First visit Results DDD* DJDt Spondylolysis Osteopenia Scoliosis Normal Follow-upvisit Results DDD DJD
Spondylolysis
Criteria f o r A p p r o p r i a t e Utilization
Underutilization of plain l u m b a r x-rays was identified as failure to obtain such x-rays in the care of patients m e e t i n g any of the above criteria or in the care of any other patient with pain persisting longer than three w e e k s from the date o f the index visit. Overutilization was identified in cases w h e r e x-rays had b e e n obtained on the first visit in the care of patients w i t h o u t one of the above indications or those for w h o m x-rays had b e e n obtained prior to the c o m p l e t i o n of a t h r e e - w e e k trial of conservative therapy. No case of cauda equina s y n d r o m e had b e e n identified and o n l y two patients had manifested mild objective n e u r o m o t o r deficits. Therefore, referrals and MRI or CT scans w e r e considered a p p r o p r i a t e w h e n a pa-
Scoliosis Normal Computed tomography scanning First visit Follow-upvisit Results Disc herniation Normal Magnetic resonanceimaging scanning First visit Follow-upvisit Results Disc herniation DJD Congenitalnarrowing * DDD = Degenerativedisc disease. t DJD = Degenerativejoint disease.
2o/183 (i 1.o%) 3 (15.0%)
5 i 2 2
(25.0%) (5.0%) ( i 0.0%) (10.0%)
7 (35.0%) 18/71 (25%) 6 (33.3%)
i (5.6%) i (5.6%) i (s.6%)
9 (50.0%) 0/183 (0.0%) 4/71 (5.6%) 3 (75%)
i (25%)
0/183 (0.0%) 14/71 (19.7%) 12 (86%) I (7.0%) I (7.0%)
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,..JOURNALOFGENERALINTERNALMEDICINE, Volume 7 (September/October), 1992 TABLE 3
Utilization of Medical Servicesfor Acute Low Back Pain According to SuggestedGuidelines(N ~ 183) Overutilization
Underutilization
Service
ServiceNot Expected
ServiceObserved
Rate
ServiceExpected
Lumbar x-ray Magnetic resonanceimaging/ computed tomography Subspecialty referral
85
10
12%
98
168 168
12 23
7% 14%
15*
ServiceNot Observed 70 7*
Rate 71% 47%
*Since the criteria for magnetic resonanceimaging/computed tomographyscanningand subspecialtyreferral were very similar, underutilization was consideredto haveoccurredonly when neither servicehad beenprovided. Among the eight patients with indicationswho had receivedsuch services,six had receivedscans, five had received referrals, and three had received both scans and referrals.
been proven, s, 15.16 Therefore, physical therapy referrals were considered to be of questionable appropriateness when obtained prior to the completion of four weeks of conservative therapy. No criterion for underutilization was considered. For plain x-rays, MRI/CT scans, and subspecialty referrals, comparisons between the observed number and the number expected based on the guidelines were performed with the chi-square test.
RESULTS Characteristics of the Study Population One hundred eighty-three patients presenting with acute low back pain met the inclusion criteria for the study. Table 1 summarizes the demographic characteristics of the patients and the details of the history and physical examination at the time of the index visit. Thirty-nine percent of the patients had made more than one visit for the episode of acute low back pain. The mean number of follow-up visits was 1.5 (range 1 - 6).
Diagnostic Evaluation Table 2 reviews the frequency and results of diagnostic testing in the study sample. Thirty-two percent of all patients ( 5 9 / 1 8 3 ) met one of the suggested criteria for early plain lumbar radiography. Of these patients, 17% ( 1 0 / 5 9 ) had received radiography at the index visit. Lumbar x-rays were subsequently obtained for 46% ( 1 8 / 3 9 ) of the patients with symptoms lasting longer than three weeks. Overall, 71% ( 7 0 / 9 8 ) of the patients meeting guidelines for the use of plain x-rays had not received this test. Twelve percent ( 1 0 / 8 5 ) of the patients who did not meet any guideline criteria had received lumbar x-rays (Table 3). The difference between the total number of x-rays observed (38) and the number expected based on the guidelines (98) was significant (p < 0.0001). T e n percent of the patients had undergone advanced radiographic imaging of the lumbar spine (4 CT s c a n s and 14 MRI scans). Eight of these patients had reported persistent sciatica and one had had asymmetric deep tendon reflexes. No patient undergoing CT or
MRI scanning had had objective findings of weakness or sensory loss. The mean time from the index visit to obtaining these studies was 5.5 weeks. Thirty-three percent ( 6 / 1 8 ) of the scans had been obtained within four weeks of the index visit. Among 12 patients scanned after four weeks of therapy, six had had no neurologic complaint or deficit and no apparent suspicion of malignancy or infection. Two-thirds of all scans ( 1 2 / 1 8 ) were considered inappropriate based on the suggested guidelines. Among the patients not meeting guideline criteria, 7% had received scans (Table 3). The difference between the total number of CT and MRI scans observed (18) and the number expected based on the guidelines (15) was not significant (p > 0.05). Fifteen patients had had persistent sciatica or neurologic changes after four weeks of conservative therapy. Since guidelines for MRI/CT scanning and those for surgical referral are largely the same, underutilization was considered to have occurred when a patient had received neither service. Seven patients had not received either of the services, for an underutilization rate of 47%. The symptoms of all seven patients had subsequently resolved with prolonged conservative therapy. Sixty-seven percent ( 1 2 / 1 8 ) of the studies had been ordered by the primary care physician, and the remainder had been ordered by a subspecialist. Among the patients referred for subspecialty evaluation, 32% ( 9 / 2 8 ) had undergone CT or MRI scanning prior to referral and an additional 25% ( 7 / 2 8 ) had had scans obtained after referral (the timing of the two scans relative to referral could not be determined).
Therapy/Referrals The prescription of nonsteroidal anti-inflammatory drugs was documented in 61% of cases and the prescription of muscle relaxants was documented in 38%. A specific prescription for bedrest was recorded in only 30% of cases, exceeding two days in 70% of these (mean duration 3.7 days). A standard series of prescribed flexion exercises was documented in 32% of cases. Table 4 summarizes the patterns of subspecialty
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Schroth et al.. RESOURCEUSE; FOR LOW BACK PAIN
and physical therapy referral. Immediate referral to orthopedic or neurosurgical subspecialists had occurred in 2% of cases ( 4 / 1 8 3 ) . Only one of these patients had had mild neuromotor deficits. In addition, referral to physical therapy had been made in 7% ( 1 3 / 1 8 3 ) of cases at the time of the index visit. Thirty-four percent ( 2 4 / 7 1 ) of the patients seen more than once had been referred to orthopedics or neurosurgery. Two of the patients had had neuromotor deficits and four others had had persistent sciatica. The mean time from the index visit to the follow-up subspecialty referral was 10.9 weeks (range 2 - 28). Including the four immediate subspecialty referrals, 32% ( 9 / 2 8 ) of the referred patients had been seen by subspecialists within four weeks of the index visit. Among the 19 patients referred after four weeks of conservative therapy, only four met the guideline criteria for surgical referral. Overall, 82% of subspecialty referrals were considered inappropriate. Among the patients not meeting guideline criteria for referral, 14% had received such referrals (Table 3). The difference between the total number of referrals observed (28) and the number expected based on the guidelines (15) was significant (p < 0.001). Review of the subspecialty care provided to all referred patients revealed three cases in which specialized therapy had been provided. One patient had had epidural steroid injection and two had had laminectomies for disc herniation, one with persistent sciatica and one with sciatica and deep tendon reflex loss. The remaining patients had been treated with continued nonsteroidal anti-inflammatory medications and, in some cases, physical therapy referral. Thirty-four percent of the patients seen more than once had been referred to physical therapy. The mean time to referral was 7.3 weeks (range 1 - 36). Including the 13 immediate referrals, 68% of all referrals to physical therapy had occurred less than four weeks from the index visit and were therefore considered of questionable appropriateness. During a mean follow-up period of six months, no patient had been found to have a serious underlying illness.
DISCUSSION This study provides a descriptive evaluation of the medical care and resource utilization for patients with acute low back pain in a primary care setting. The patients evaluated in this study represented a relatively homogeneous group with acute low back pain. The exclusion criteria eliminated patients with chronic back pain and those with frequent relapses. Several cautions should be observed in the interpretation of these data. First, all cases were from the practice of a single urban, university-affiliated HMO. The results may not be representative of practices in other settings or other regions. Second, all data were
TABLE; 4 Utilization of Referral Services
First visit (N = 183) Orthopedics Neurosurgery Physicaltherapy Follow-up visit (N = 71 ) Orthopedics Neurosurgery Physicaltherapy
3 (I .6%) I (0.4%) 13 (7.0%) 13 (I 8.0%) 11 (15.5%) 24 (34.0%)
obtained from retrospective review of medical records. Misclassification bias may have occurred if pertinent findings from the clinical history and examination were absent from the patient's record. Although out-of-plan care had been sought by a few patients in the sample, the setting of a closed-panel HMO permitted nearly complete capture of health care resource utilization for major diagnostic and therapeutic interventions. Finally, the appropriate care of acute low back pain remains controversial, and some readers may therefore disagree with the appropriateness criteria employed in this study. Nonetheless, we believe that the use of explicit and well-documented guidelines was preferable to a more implicit case-by-case, judgment-based method. Plain radiography of the lumbar spine was substantially underutilized relative to suggested guidelines, though a small amount of overutilization was also found. Strict adherence to current recommendations for selective ordering of lumbar radiography would have led to a significant increase in the number of x-rays obtained (from 21% to 54%). These findings are consistent with those of two other studies of plain radiography utilization in the management of low back pain. 17. 18Despite the underutilization of x-rays in these three studies, no adverse effect on diagnostic accuracy or patient outcomes has been detected. Based on the rarity of serious diagnoses for patients with acute low back pain and the poor sensitivity and specificity of lumbar x-rays, the practice of obtaining x-rays routinely for patients with back pain has been discouraged. 3, x9 Although the recommended guidelines for obtaining x-rays have been revised substantially, the results of these three studies suggest that such guidelines might be narrowed further. Nevertheless, it should be noted with caution that none of these studies has had adequate statistical power to determine reliably the effect of underutilization on rare yet serious causes of acute low back pain. Advanced radiographic procedures (CT and MRI scans) were overutilized according to the guidelines. It is interesting that most of the CT and MRI scans had been ordered by the primary care physician, frequently prior to subspecialty referral. We had postulated that early subspecialty referral might lead to excessive utilization of expensive diagnostic technology by the sub-
JOURNALOFGENERALINTERNALMEDICINE,Volume 7 (September/October), 1992
specialist; however, most of the excessive utilization in this setting was driven by the primary care physician. Although the judicious use of advanced imaging procedures by the primary care physician may save an unnecessary referral, this evidence suggests that more appropriate referral patterns alone will not substantially improve the p r o p e r use of these technologies, and that emphasis on altering the behavior of primary care physicians may be necessary. Referrals were underutilized in the care of several patients with persistent neurologic complaints w i t h o u t adverse consequences. Again, however, this study lacks p o w e r to evaluate such consequences, and, thus, underutilization must continue to be viewed critically. On the other hand, most referrals were considered inappropriate. Back pain can be a highly distressing symptom to patients, and therefore the " t h e r a p e u t i c " benefit of a second opinion may be important. Nevertheless, for patients unlikely to be considered surgical candidates, the need for a subspecialty opinion seems questionable. Perhaps if the primary care physician presented a more confident and reassuring approach, such referrals could be limited further. Physical therapy referrals had b e e n given in many cases prior to an adequate trial of conservative therapy. Physical therapy lacks evidence of efficacy and generates substantial medical care costs (charge per visit at o u r center is $90, mean n u m b e r of visits is 4). Under these circumstances, physical therapy referrals should probably be reserved for patients w h o have failed less expensive conservative therapies with d o c u m e n t e d efficacy. Appropriate guidelines for the use of physical therapy services for patients w h o do not improve with a trial of conservative therapy must await further studies of the timing and efficacy o f these interventions. This study documents substantial deviation from published clinical guidelines among primary care clinicians during the care of patients w h o have acute low back pain. If such variation stems from a lack of familiarity with suggested guidelines, then explicit dissemination and implementation of these clinical guidelines might lead to more appropriate management of this condition. Alternatively, it is possible that patient demands for reassurance may be driving the utilization of medical resources for this problem, i n d e p e n d e n t of the physician's preferred practice approach. Investigation of this possibility is necessary, since interventions di-
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rected at altering physician behavior alone may have little effect on patient attitudes and demands. Finally, the study of larger and more diverse clinical databases is necessary to determine w h e t h e r adherence to clinical guidelines for acute low back pain improves patient outcomes in a cost-effective manner.
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