470 Journal of Pain and Symptom Management
vol. 7 No. 8 November I992
Chest Pain: J. Gayle Beck, PhD, Thomas J. Chase, BA, M. Andrew Berisford, MA, and Heinrich Taegtmeyer, MD Depmtmentof Psychology u. G.B, 7’.J,C, M.A. B.), University of Houston; and Univekty of Exa Medical Schoolat Houston (H.T), Departmentof Internal Medicine,Division of Cardiology, Houston, Texas
The pnkna~ purpose of this report is to extend the range of the Multidimensional Pain Inventory (IMPI) to include patients with nonorganic chest pain. Previous research with the WI has not included this patient population, although thk instrument has been wed to derive an empirically based taxonomy of patient responses to chronic pain. Scale scores are provided for a sample of 43 chest pain patients and compared with norma!~ivescores fknn samples of chronic lower back pain patients and patients suffering porn temposvmandibular disorokr. The MPI taxonomy was applicablefor only 34.8 % (N = 15) of this sample. Scale intercorrelations are examined and compared with those:derived during development of the MP! to explore reasons for this low classzfication rate. The results are discussed in light of cognitive-behavioralfactors present in persistent chest pain, with implications for scale o?evelopmentand use of the MPI. J Pain Symptom Manage 1992;7:470-477.
Chronic pain, angina, psychosocial adjustment
To many health service providers, chronic pain syndromes are characterized by their complexity, subjectivity, and resilience.tS Current cognitive-behavioral conceptualizations suggest that pain is best described as a multidimensional perceptual phenomenon, which can be comprised of both psychologi-
Ad&es n#ht
?qw.sls to:J. Gayle Beck, PhD, Depart-
ment of Psychology,Universityof Houston, 4800 CalhounStreet, Houston,TX 772045341. Accepedfiipuh’icatrimion:May7,1992. @ U.S. Cancer Pain Relief Committee, 1992 Published by Ebevier, New York, New York
cal and physical factors.sn4 Based on this formulation, the interdisciplinary study of pain has evolved, including the development of new approaches to assessment and treatment. To date, a number of authors have highlighted the need for comprehensive assessment strategies, including those that incorporate psychological factors for chronic pain. *t5-’ According to these recommendations, the specific dimensions of relevance include a determination of the patient’s perceived severity of pain, the degree of interference that pain causes in various life
08853924/92/$5.00
Vol.7 No. 8 NovembwI992
NonorganicChestPain
severity, CQU.rOl
n, negative mood states,a
indicate low levels of activity, common acti
instrument comprises the impact of pain on the
g that it is a stable classificapotential utility for chronic
construct validity via a fhctorial validity procedure. PI contains 52 The final form of items divided into three sections, each of which contains several subscales. Section I evaluates subjective aspects of ence (perceived interference, pain, perceived support fr0m significant others, self-control, and negative mood). Section II examines the patient’s of significant others’ responses pressions, in particular and distracting responses. Section III evaluates the patient’s participation in four areas of common daily activities: household chores, outdoor work, activities away from home, and social activities. A general activity index is computed by averaging participation in these areas. To date, the MPI has been used to establish an empirically derived taxonomy of patient responses to chronic pain.9 This taxonomy has been employed with patient populations as diverse as those suffering from temporomandibular disorders (TMD’O) and patients suffering from chronic low back pain.g According to the authors, this taxonomy can classify 95% of all chrcsnic pain patients into three unique subgroups of patients: dysfunctional, interpersonally distressed, and adaptive capers. Within this scheme, dysfunctional patients report high levels of pain
speculation but scant resear
among chest pain ( closer examination in important ways, such as less severe symp toms of anxiety and less frequent use of psychotropic medication.rs*14 These differences suggest that a closer look at the presenting pain complaints of these patients is warranted. In particular, comparison of the pain profiles of CP patients with other chronic pain patients could assist greatly in proper diagnosis and management. In this report, the MPI was selected for this purpose, based on its multidimensional construction and taxonomy system.
Subjects c_ included 43 patients with persisvu b’ects .l tent, nonorganic chest pain, who were screened to rule out coronary artery disease (CAD) and other physical disorders. Screen-
Beck et al.
472
Irol. 7 No. 8 Nowenzber1992
ing methods included thallium scintigraphy (IV= II), catheterization (N= 22), treadmill testing (N= 7)) and echocardiogram (IV= 3). This diversity of screening methods is typicall5 and reflects the referring cardiologists’ assessments of patients’ pain profiles. All patients in this sample were referred to the study by cardiologists from a university hospital cardiology service, following complete physical examination to rule out other physical diagnoses, inchtding musculoskeletal, pericardial, pleural, and gastrointestinal disorders. All patients with persistent chest pain in the absence of evidence of CAD were invited to participate in the study. Approximately 65% of patients contacted participated, with the remainder declining due to scheduling difficulties, lack of transportation, or time constraints. The average age of the subjects was 42.3 yr (SD = 13.4). Of the patients, 30 (69.8%) were female. The average duration of pain was 3 yr, 3 mo (SD = 3.9), with the majority reporting pain daily (43.9%) or 2-3 times/wk (22%). Pain duration ranged from O-l hr (N= 16,39.0%) to greater than 12 hr (N= 8, 19.5%), with the majority of patients falling between these two extremes. Regarding medication, 15 patients (35.7%) reported no medication use, whereas 7 (16.7%) reported medication use several times per day. The remainder of this patient sample fell between these two extremes in medication use. Medications included p blockers, calcium channel blockers, muscle relaxants, and mild sedatives for sleep.
150 patients (51% female) with an average duration of pain of 6.9 yr (SD = 9.7). The average age of this sample was 44.4 yr (SD = 13.8). The TMD patient sample included 100 patients (86% female) with an average pain duration of 4.3 yr (SD = 5.7). Average age of the TMD sample was 31.1 yr (SD = 10.2) (T Rudy, personal communication, July 1991) .a The MPI Scoring Program also classifies patient responses according to the taxonomy profiles, described above. Specific decision rules are used in this classification. It is possible for a patient to report an anomalous profile, which occurs when scores on specific scales do not fit a given profile and theoretically are impossible. For example, current cognitive theories of depression suggest that increases in dysphoric mood leads to diminished feelings of self-control.17 Thus, the life control and affective distress scales theoretically should be inverted. If both are elevated, is automatically coded as a profile anomalous. Similarly, when scores on the Pain Severity and Interference scales are inverted, a patient’s profile is coded as anomalous. Likewise, when a patient indicates high levels of punishing, solicitous, and distracting responses from significant others, an anomalous profile is coded. According to the authors of the MPI, these conditions indicate that the patient may not have understood the questions correctly. Additionally, if a patient is not involved in an ongoing relationship or does not have a close friend, several subscales cannot be completed, resulting in an inability to classify the profile.
Multidknsional
Procedure
Pain Inventory
Each subject completed the Multidimensional Pain Inventory (MPI). The MB1 was scored using Version 2.1 of the MPI Computer Scoring Program.16 This program pr* vides raw and T-score results based on norms for chronic pain patients, described in I&-I-IS and col1eagues.s To facilitate comparison of scores from the CP patient group, norms from a sample of patients with low back pain ad a sample of patients with TMD were employed. These norms were provided by the MPI scale developers, based on patient samples presenting to an outpatient pain clinic. The low back pain sample included
All procedures were reviewed by the Committees for the Protection of Human Subjects at the University of Houston and the University of Texas Medical School at Houston. Following initial referral, subjects completed the MPI.
=Thesesamples were comprised of patientsfromthe Pain Evaluationand TreatmentInstitute,University of PittsburghMedicalCenter. We wish to express our
appreciation to Dr. T. Rudy for his help in providing the description of these patient samples and related information concerning the MPI taxonomy.
Vol.7 No. 8 Nouember I992
Nonorganic ChestPain
473
rkrence
scale scores for in Table 1 and are corn norms for low back pain a These comparisons were
r work, activities away eral activity level, rela-
nominal a rate, to type I error rate. us, t tests were conducted at a = 0.00 separate tests.As c candy less severe disturbance from pain on eight of 13 relative to the 1
rences were
Lower back
Scale
(NZ3)
(N = 150)
Section I: psychosocial axis §I
Pain severity
52
Interference
S3
Life control
S4
Affective distress
55
Support
2.170 (1.51) 2.15a (1.81) 3.33” (1.33) 3.050 (1.69) 3.59= (1.82)
4.646 (1.00) 4.796 (8.98) 3.090 (1.53) 3.85” (1.29) 4.59* (1.43)
Section 1[I:Behavioral axis-Patients’ perceptions of how significant displays of pain (Note: N= 36 for CP sample) S6
Punishing
S7
Solicitous
S8
Distracting
Section IIk Behavioral axis-Extent for CP sample) S9
Household chores
SlO Outdoor work Sll Activities (away from home) S12 Social activities S13 Activity level (gen=aU
frsm
1.27= (1.51) 3.03a (1.89) 1.89” (1.59)
1.73” (1.62) 3.61~ ‘:z’ ( 1:46;
2.400 (1.41) 2.69” (0.97) 2.81” (1.54) 2.76O (1.11) 3.15” (1.19) other
responds
to their
1.399” (%I’ !1:51; 1.83= (1.39)
patient engages in various common activities (Note: N= 43 4.13” (1.66) 1.96” (1.31) 3.04” (1.24) 2.29” (1.09) 2.86” (0.88)
Note: Row means with common subscripts QOnot differ (P > 0.001).
2.75” (1.60) o.ss* (1.05) 2.19* (1.07) 2.050 (1.16) 1.96b (0.91)
4.29= (1.51) 1.96” (1.50) 3.03Q (0.95) 2.55O (1.13) 2.96” (0.88)
Beck et al.
474
M&i&memiod
T&b? 2 Pain Inventory ~files
C%S!5Bation
Results
Qassified (N= 15) Dysfunctional profile: N= 1 Interpersonally distressed profile: N= 5 Adaptive caper profile: N = 9 Unable to be classified (N= 28) Unanalyzable case (too much missing data): N= 7 Anomalous profile: N= 21 Reasons for anomalous prOfik!S (not mutually exclusive): Negative correlation of pain severity (scale 1) and interference (scale 2) scales: N= 10 Simultaneous elevation of punishing responses (scale6), solicitous responses (scale 7). and distracting responses (scale 8) scales: N= 3 Simultaneous elevation of life control (scale 3) and affective distress (scale 4) scales: N= 8 Unknown: N= 7
patients (34.8%) were able to be classified within the MPI taxonomy. The largest group (N= 9) fit the adaptive caper profile, while five patients were categorized within the interpersonally distressed profile, and one patient fit the dysfunctional profile. Of the remaining 28 patients, seven profiles were unanalyzable due to the lack of a spouse or significant other; 21 patients had anomalous profiles. In examining the reasons for anomalous profiles, negative correlations of the pain severity and interference scales were noted for ten patients; &e punishing, solicitous, and distracting subscales were all elevated for three patients; and the life control and affective distress scales were both elevated for eight patients. In each event, these anomalies violated the decision rules for MPI classification and represent theoretically impossible profiles. The ratings for anomalous profiles are not mutually exclusive, and another seven patients were rated as anomalous by the scoring program, for unknown reasons. Although it would have been desirable to explore statistically the profiles of the patients who were coded as anomalous for unknown reasons, this was not possible given the small sample size. To examine the reasons for this low rate of classification, interscale Pearson correlations were computed and compared with intercor-
Vol. 7 No. 8 Nimmber 1992
relations derived from a heterogeneous chronic pain sample in the development of the MPI (see Table 3). As can be seen, the pattern of scale intercorrelation observed in the CP sample was quite different from the pattern noted in the original validation sample. For example, there was no correlation between pain severity and social activity level (T = -0.10, NS), unlike the significant correlation observed in the original validation sample (r = -0.27). However, interference from pain correlated significantly with affective distress (r= 0.37, P< 0.05) in the CP sample, unlike the nonsignificant ccrrelation (r = 0.06) observed in the validation sample. Overall, of 19 significant interscale correlations, only seven were similar in direction and in magnitude with the patterns observed in the original validation of the MPI. Given that the MPI taxonomy system was derived from the variance-covariance matrices of the MPI subscales with the original validation sample, the differences in interscale correlation noted with the CP sample indicate that the taxonomy is not appropriate for this patient group.
The purpose of this investigation was to extend the range of the MPI to include patients with chronic, nonorganic chest pain. Our results indicate that MPI scale scores for the CP patient sample more closely resemble values obtained from TMD patients than those from lower back pain patients. However, when the MPI taxonomy system was applied to this sample of nonorganic chest pdn patients, only 34.8% of the sample was abie to be cIassified into existing profiles. Comparison of the interscale correlations with those derived during the development of the MPI indicate a markedly different pattern, suggesting differences in the cognitive-behavioral nature of pain in nonorganic chest pain and rendering the empirically derived taxonomy inappropriate for use with these pain patients. This investigation is the first to compare pain profiles of nonorganic chest pain patients with other chronic pain patients. Relative to low back pain patients, CP patients had significantly lower levels of pain
cm
Sl Sl s2 s3 s4 s5 S6" s7a S8Q s9 SlO Sll s12
S2
$3
S4
s5
S6
57
S8
le S9
@-I S1Q -
s11
0.58 (0.09) -0.16 -0.15 (0.58) (0.05) 0.28 0.37 -0.52 (-0.15) (8.06) (-aAS) -0.13 -0.02 0.59 -0.35 (0.26) (-0.03) (0.34) (-0.52) 0.38 0.39 -0.29 0.26 -0.28 (0.00) (-0.38) (0.03) (-0.14) (0.20) -0.05 0.03 0.65 -0.18 0.75 -0.21 (0.34) (0.56) (0.31) (-0.08) (0.04) (-0.29) 0.20 0.17 0.43 -0.08 0.41 0.07 0.52 (0.10) (0.42) (0.05) (0.11) (-G.01)(-0.24) (8.49) 0.02 -0.01 0.25 -0.07 -0.03 -0.27 0.10 -0.06 (-0.27)(-0.31) (-0.25) (0.16) (-0.21) (0.17) (-O.31) (-0.17) -0.43 -0.39 Q.Gt? -0.17 0.18 -0.23 0.08 0.00 -0.06 (-0.10) (0.08) (-G.18)(-0.04) (0.03) (0.14) (-0.15) (0.01) (0.12) -0.04 -0.12 0.11 -8.13 0.28 -O.18 0.20 0.43 0.21 (-0.29)(=&05) (-0.19) (0.19) (-0.20)(-0.91)(-0.10) (-0.07) (0.27) a.10 -0.22 0.12 -0.43 0.13 -0.19 0.09 0.11 0.26 (-0.27) (0.04) (-0.02)(-0.31) (-O.11) (0.03) (0.08) (0.19) (0.23)
0.34 (0.31) 0.32 0.52 (O.05) (0.49)
Now ForN= 43,values It0.30, PC 0.05; for N= 35, +values i 0.33, PC 0.05; andfor original validation sample, rvahtes k 0.20, PC: iJ.05. Worrelations computed with N= 36, owing to 7 cases without a significant other (otherwise, N= 43).
severity, less interference from pain, less affective distress, and greater perceived support from significant others. This suggests that the nonorganic chest pain patients are less affected by #theirpain symptoms, relative to the low back pain sample. In many respects, the pain profiles observed in the Cl? sample resembled those of the TMD sample. In interpreting these comparisons, the fact that the low back pain group reported a markedly longer duration of pain relative tu the other two patient groups may be relevant. In particular, the extent of interference from pain and behavioral t-estriction (Section III) may be influenced by pain duration, in addition to pain site. Clinical application of the MPI would be assisted by examining the impact of pain duration on MPI profile scores. In considering the similarities observed between the TMD and CP samples, it is notable that the MPI taxonomy performs well with T&ID patients, in contrast to the present data. For example, Rudy and colleagueslo reported that only 6% of an patients could independent sample of
not be classified with the MPI taxonomy, us, although and CP patients respect to mean scale between these two mini& when multivariate profile classification is involved. This rices in the variance parameI in these two chronic pain patient samples. Possibly, the intermittent nature of both nonorganic chest pain and temporomandibular pain accounts for similarity in pain severity, lessened interference from pain, and greater behavioral activity in a number of domains. However, important dimensions of difference appear salient in this patient contrast, as evidenced by the strikingly dissimilar rates of classiflcatian. Several methodologis issues are relevant in considering these data. First, the size of the CP sample employed in this study was smaller than the sample sizes that comprised the two comparison groups. As a result, the norms provided here may not be stable and need to nt sambe replicated in a larger, indepe pattern ple of CP patients. Additionally, of interscale correlations noted from the CP
476
Beck et al.
patient data may not be stable, given the small sample size. To derive a useful taxorromy of pain profiles for CP patients, continued use of this instrument with these patients is warranted. Further research also may benefit from consideration of the influence of social desirability on MPI scale responses. As noted above, the majority (69.8%) of the CP sample was female. Further consideration of the importance of gender differences in MPI profiles awaits a larger sample of CP patients. Despite these methodologic caveats, it is notable that the MPI taxonomy system performed poorly with this sample. A constraint of this classification system is the necessity for patients to be involved in an ongoing relationship or marriage. Thus, ‘7 members of our sample could not be classified owing to the fact that they were without a significant other (e.g., spouse, intimate friend, or best friend). Although this is unusual, it has been documented that patients with nonorganic chest pain often carry comorbid psychiatric diagnoses, particularly depressive and anxiety disorders. ll~* Prospective longitudinal studies have documented the fact that over time, some percentage of these patients lose occupational functioning and withdraw se cially.1g*20Thus, this aspect of the CP sample utilized here is neither unusual nor atypical of this patient population. Adaptation of the MPI to accomodate those patients who are severely socially withdrawn appears necessary. In a different vein, the pattern of interscale correlation observed in the CP sample was sufficiently different from that derived with the original validation sample to account for this low classification rate. This correlational structure suggests important features of the cognitiv&ehavioral nature of chronic chest pain. As noted in Table 3, a significant positive correlation was noted between pain severity and pain interference, suggesting overlap in the assessment of these two pain dimensions in CP patients. A significant positive correlation was noted between interference and affective distress, indicating that the degree of impairment from episodic bouts of chest pain corresponds with greater emotional disturbance in these patients. As observed in the validation sample, a signig-
VOL7 No. 8 November 6992
cant negative correlation was noted between social activity level and affective distress. However, a nonsignificant correlation was noted between social activities and pain severity, suggesting that behavioral impairment does not necessarily correspond with greater levels of pain. Additionally, a low ( r = 0.16) correlation was observed between pain severity and perceptions of lie control, indicating that unlike other samples of chronic pain patients, CP patients do not report increased feelings of helplessness with more severe levels of pain. It is possible that the episodic nature of chest pain accounts for this correlation pattern, as the majority of the sample indicated that when symptoms occur, the duration of pain is often less than 12 hr. In particular, nonorganic chest pain often occurs suddenly and is described as “coming from out of the blue,” without provocation from exertion or exercise. Daily symptom occurrence is unusual and most patients report extended symptom-free intervals.** Thus, unlike other forms of chronic pain, nonorganic chest pain appears to be described by different cognitive-behavioral features. It is notable that related investigations have provided some degree of independent validation for the three pain profiles that comprise the MPI taxonomy. For example, Etscheidt and Braver-man*’ found support for these profiles, using the MMPI, although 25% of these authors’ sample was not able to be classified with the MPI, owing to similar reasons as noted in Takle 2. Thus, it appears that the unusually high 95% classification rate reported in Turk and Rudy’s9 replication sample may not be able to be reproduced in other samples of chronic pain patients. In summary, this paper reports scale scores for a sample of 43 patients with nonorganic chest pain, using the MPI. Nonorganic chest pain patients appear less handicapped by pain, relative to low back pain patients, although they indicate moderate pain severity and affective distress resulting from pain symptoms. Continued examination of pain profiles in patients with chronic, nonorganic chest pain appears warranted, particularly given long-standing confusion in the diagnosis and management of these patients,*0 MPI appears to be a useful instrument for
Ir,! 7 No. 8 Novder
I9542
Nmwganic Chest Pain
~sycb~~~~cal assessment data. choll988;56:233-238.
477
Consult Chn
psy-
, TurlrDC, Zaki , Curtin K’.An empirical Qxometric alternative to classification of temporo mandibular disorders. Pain 1989;36:31 l-326. Il.
itman BD, Basha chest p 147:1548-1552. Flaker G, DeRosear k, P depression in CardioL without coronary artery disease and with panic disorder. J Affective Disord 1987;13:51-59.
meters of chronic pain and valua’slr for under syxndromes 0f chronic chest pain patients.
13. Beck Be&ford MA, Taegtrrneyer A. Panic ptoms in chest pain with artery disease: a comparison with panic disorder. Bebav Ther 1990;21:211-252.
dbya adon,
nett : an fw-
1. Fordyce WE. Behavioral methods in chronic pain and illness, St Iouisz CV Mosby, 1976. 2. Eeefe FJ. Behavioral assessment and treatment of chronic pain. j Consult Clin Psycho1 1982;50:896911. ichenbaum D, Genest 3. Turk DC, behavioral m tine: a cognitive behavi tive. New York: Guilford, 1983.
2Ild
pec-
4. Turk DC, Rudy TE, Boucek CD. The contribution of psychological factors to the experience of chronic pain. In: War-fieldCA., ed. Manual of pain management. Philadelphia: JB Lippincott, 1992 (in press). , Ziter RE, Ahem DIL Failure in the 5. Follick operant treatment of chronic pain. In: Foa EB, Emmelkamp P, eds. Failures in behavior therapy, New York John Wiley, 1985.197-223. 6. Fred&son I_W,Lynd R8, RosJ. Methodology in the measurement of pain. Behav Ther 1979;9:486488. 7. Williams R Toward a set of reliable and valid measures for chronic pain assessment and outcome research. Pain 1988;35:239-251. 8. Rerns RD, Turk DC, Rudy TE. The West IiavenYale Multidimensional Pain Inventory (WI-IYMPI). Pain 1985;25:345-356. 9. Turk DC, Rudy TE. Toward an empirically derived taxonomy of chronic pain patients: integration of
rosclerotic coronary beat-t disease: arks, methods of study, and clinical features, differential diagnosis, and clinical spectrum. In: Hurst JW, ed. The heart, arteries, and veins. New York McGraw-Hill,1990:961-1001. 16. Rudy TE. Muhiaxial assessment of pain: muhidimensional pain inventory [Computer program manual]. Pittsburgh: University of Pittsburgh Medical Center, 1989. 17. Rehm LB. A selfcontrol model of depression. Behav Ther 1977;8:787-804. Confidence intervals for multiple comparisons and the misuse of the Bonferroni inequality. BrJ Math Stat Psycho1 1973;26:5=0. 19. Ockene IS, Shay MJ, Alpert JS, Weiner BH, &fen JE. UnexpGned chest pain in patients with normal coronary arteriograms. N Engl J 1249-11252. 20. Paarernak RC, Thibault GE, Savob M, D&n& RW, Hutter AM. Chest pain with angiographically insignificant coronary arterial obstruction. Am J Med 1980:813-817. 21. Etscheidt M, Braverman B. Further validation of the multidimensional pain inventory using the MMPI. Paper presented at the annual convention of the Association for the Advancement of Behavior Therapy, San Francisco, CA, 1990. 22. Wooley CF. From irritable heart to mitral valve prolapse: British army medical reports, 1860 to 1870. Am-J Cardio11985:55:1107-1109.
vol. 7 No. 8 November I992
Chest Pain: J. Gayle Beck, PhD, Thomas J. Chase, BA, M. Andrew Berisford, MA, and Heinrich Taegtmeyer, MD Depmtmentof Psychology u. G.B, 7’.J,C, M.A. B.), University of Houston; and Univekty of Exa Medical Schoolat Houston (H.T), Departmentof Internal Medicine,Division of Cardiology, Houston, Texas
The pnkna~ purpose of this report is to extend the range of the Multidimensional Pain Inventory (IMPI) to include patients with nonorganic chest pain. Previous research with the WI has not included this patient population, although thk instrument has been wed to derive an empirically based taxonomy of patient responses to chronic pain. Scale scores are provided for a sample of 43 chest pain patients and compared with norma!~ivescores fknn samples of chronic lower back pain patients and patients suffering porn temposvmandibular disorokr. The MPI taxonomy was applicablefor only 34.8 % (N = 15) of this sample. Scale intercorrelations are examined and compared with those:derived during development of the MP! to explore reasons for this low classzfication rate. The results are discussed in light of cognitive-behavioralfactors present in persistent chest pain, with implications for scale o?evelopmentand use of the MPI. J Pain Symptom Manage 1992;7:470-477.
Chronic pain, angina, psychosocial adjustment
To many health service providers, chronic pain syndromes are characterized by their complexity, subjectivity, and resilience.tS Current cognitive-behavioral conceptualizations suggest that pain is best described as a multidimensional perceptual phenomenon, which can be comprised of both psychologi-
Ad&es n#ht
?qw.sls to:J. Gayle Beck, PhD, Depart-
ment of Psychology,Universityof Houston, 4800 CalhounStreet, Houston,TX 772045341. Accepedfiipuh’icatrimion:May7,1992. @ U.S. Cancer Pain Relief Committee, 1992 Published by Ebevier, New York, New York
cal and physical factors.sn4 Based on this formulation, the interdisciplinary study of pain has evolved, including the development of new approaches to assessment and treatment. To date, a number of authors have highlighted the need for comprehensive assessment strategies, including those that incorporate psychological factors for chronic pain. *t5-’ According to these recommendations, the specific dimensions of relevance include a determination of the patient’s perceived severity of pain, the degree of interference that pain causes in various life
08853924/92/$5.00
Vol.7 No. 8 NovembwI992
NonorganicChestPain
severity, CQU.rOl
n, negative mood states,a
indicate low levels of activity, common acti
instrument comprises the impact of pain on the
g that it is a stable classificapotential utility for chronic
construct validity via a fhctorial validity procedure. PI contains 52 The final form of items divided into three sections, each of which contains several subscales. Section I evaluates subjective aspects of ence (perceived interference, pain, perceived support fr0m significant others, self-control, and negative mood). Section II examines the patient’s of significant others’ responses pressions, in particular and distracting responses. Section III evaluates the patient’s participation in four areas of common daily activities: household chores, outdoor work, activities away from home, and social activities. A general activity index is computed by averaging participation in these areas. To date, the MPI has been used to establish an empirically derived taxonomy of patient responses to chronic pain.9 This taxonomy has been employed with patient populations as diverse as those suffering from temporomandibular disorders (TMD’O) and patients suffering from chronic low back pain.g According to the authors, this taxonomy can classify 95% of all chrcsnic pain patients into three unique subgroups of patients: dysfunctional, interpersonally distressed, and adaptive capers. Within this scheme, dysfunctional patients report high levels of pain
speculation but scant resear
among chest pain ( closer examination in important ways, such as less severe symp toms of anxiety and less frequent use of psychotropic medication.rs*14 These differences suggest that a closer look at the presenting pain complaints of these patients is warranted. In particular, comparison of the pain profiles of CP patients with other chronic pain patients could assist greatly in proper diagnosis and management. In this report, the MPI was selected for this purpose, based on its multidimensional construction and taxonomy system.
Subjects c_ included 43 patients with persisvu b’ects .l tent, nonorganic chest pain, who were screened to rule out coronary artery disease (CAD) and other physical disorders. Screen-
Beck et al.
472
Irol. 7 No. 8 Nowenzber1992
ing methods included thallium scintigraphy (IV= II), catheterization (N= 22), treadmill testing (N= 7)) and echocardiogram (IV= 3). This diversity of screening methods is typicall5 and reflects the referring cardiologists’ assessments of patients’ pain profiles. All patients in this sample were referred to the study by cardiologists from a university hospital cardiology service, following complete physical examination to rule out other physical diagnoses, inchtding musculoskeletal, pericardial, pleural, and gastrointestinal disorders. All patients with persistent chest pain in the absence of evidence of CAD were invited to participate in the study. Approximately 65% of patients contacted participated, with the remainder declining due to scheduling difficulties, lack of transportation, or time constraints. The average age of the subjects was 42.3 yr (SD = 13.4). Of the patients, 30 (69.8%) were female. The average duration of pain was 3 yr, 3 mo (SD = 3.9), with the majority reporting pain daily (43.9%) or 2-3 times/wk (22%). Pain duration ranged from O-l hr (N= 16,39.0%) to greater than 12 hr (N= 8, 19.5%), with the majority of patients falling between these two extremes. Regarding medication, 15 patients (35.7%) reported no medication use, whereas 7 (16.7%) reported medication use several times per day. The remainder of this patient sample fell between these two extremes in medication use. Medications included p blockers, calcium channel blockers, muscle relaxants, and mild sedatives for sleep.
150 patients (51% female) with an average duration of pain of 6.9 yr (SD = 9.7). The average age of this sample was 44.4 yr (SD = 13.8). The TMD patient sample included 100 patients (86% female) with an average pain duration of 4.3 yr (SD = 5.7). Average age of the TMD sample was 31.1 yr (SD = 10.2) (T Rudy, personal communication, July 1991) .a The MPI Scoring Program also classifies patient responses according to the taxonomy profiles, described above. Specific decision rules are used in this classification. It is possible for a patient to report an anomalous profile, which occurs when scores on specific scales do not fit a given profile and theoretically are impossible. For example, current cognitive theories of depression suggest that increases in dysphoric mood leads to diminished feelings of self-control.17 Thus, the life control and affective distress scales theoretically should be inverted. If both are elevated, is automatically coded as a profile anomalous. Similarly, when scores on the Pain Severity and Interference scales are inverted, a patient’s profile is coded as anomalous. Likewise, when a patient indicates high levels of punishing, solicitous, and distracting responses from significant others, an anomalous profile is coded. According to the authors of the MPI, these conditions indicate that the patient may not have understood the questions correctly. Additionally, if a patient is not involved in an ongoing relationship or does not have a close friend, several subscales cannot be completed, resulting in an inability to classify the profile.
Multidknsional
Procedure
Pain Inventory
Each subject completed the Multidimensional Pain Inventory (MPI). The MB1 was scored using Version 2.1 of the MPI Computer Scoring Program.16 This program pr* vides raw and T-score results based on norms for chronic pain patients, described in I&-I-IS and col1eagues.s To facilitate comparison of scores from the CP patient group, norms from a sample of patients with low back pain ad a sample of patients with TMD were employed. These norms were provided by the MPI scale developers, based on patient samples presenting to an outpatient pain clinic. The low back pain sample included
All procedures were reviewed by the Committees for the Protection of Human Subjects at the University of Houston and the University of Texas Medical School at Houston. Following initial referral, subjects completed the MPI.
=Thesesamples were comprised of patientsfromthe Pain Evaluationand TreatmentInstitute,University of PittsburghMedicalCenter. We wish to express our
appreciation to Dr. T. Rudy for his help in providing the description of these patient samples and related information concerning the MPI taxonomy.
Vol.7 No. 8 Nouember I992
Nonorganic ChestPain
473
rkrence
scale scores for in Table 1 and are corn norms for low back pain a These comparisons were
r work, activities away eral activity level, rela-
nominal a rate, to type I error rate. us, t tests were conducted at a = 0.00 separate tests.As c candy less severe disturbance from pain on eight of 13 relative to the 1
rences were
Lower back
Scale
(NZ3)
(N = 150)
Section I: psychosocial axis §I
Pain severity
52
Interference
S3
Life control
S4
Affective distress
55
Support
2.170 (1.51) 2.15a (1.81) 3.33” (1.33) 3.050 (1.69) 3.59= (1.82)
4.646 (1.00) 4.796 (8.98) 3.090 (1.53) 3.85” (1.29) 4.59* (1.43)
Section 1[I:Behavioral axis-Patients’ perceptions of how significant displays of pain (Note: N= 36 for CP sample) S6
Punishing
S7
Solicitous
S8
Distracting
Section IIk Behavioral axis-Extent for CP sample) S9
Household chores
SlO Outdoor work Sll Activities (away from home) S12 Social activities S13 Activity level (gen=aU
frsm
1.27= (1.51) 3.03a (1.89) 1.89” (1.59)
1.73” (1.62) 3.61~ ‘:z’ ( 1:46;
2.400 (1.41) 2.69” (0.97) 2.81” (1.54) 2.76O (1.11) 3.15” (1.19) other
responds
to their
1.399” (%I’ !1:51; 1.83= (1.39)
patient engages in various common activities (Note: N= 43 4.13” (1.66) 1.96” (1.31) 3.04” (1.24) 2.29” (1.09) 2.86” (0.88)
Note: Row means with common subscripts QOnot differ (P > 0.001).
2.75” (1.60) o.ss* (1.05) 2.19* (1.07) 2.050 (1.16) 1.96b (0.91)
4.29= (1.51) 1.96” (1.50) 3.03Q (0.95) 2.55O (1.13) 2.96” (0.88)
Beck et al.
474
M&i&memiod
T&b? 2 Pain Inventory ~files
C%S!5Bation
Results
Qassified (N= 15) Dysfunctional profile: N= 1 Interpersonally distressed profile: N= 5 Adaptive caper profile: N = 9 Unable to be classified (N= 28) Unanalyzable case (too much missing data): N= 7 Anomalous profile: N= 21 Reasons for anomalous prOfik!S (not mutually exclusive): Negative correlation of pain severity (scale 1) and interference (scale 2) scales: N= 10 Simultaneous elevation of punishing responses (scale6), solicitous responses (scale 7). and distracting responses (scale 8) scales: N= 3 Simultaneous elevation of life control (scale 3) and affective distress (scale 4) scales: N= 8 Unknown: N= 7
patients (34.8%) were able to be classified within the MPI taxonomy. The largest group (N= 9) fit the adaptive caper profile, while five patients were categorized within the interpersonally distressed profile, and one patient fit the dysfunctional profile. Of the remaining 28 patients, seven profiles were unanalyzable due to the lack of a spouse or significant other; 21 patients had anomalous profiles. In examining the reasons for anomalous profiles, negative correlations of the pain severity and interference scales were noted for ten patients; &e punishing, solicitous, and distracting subscales were all elevated for three patients; and the life control and affective distress scales were both elevated for eight patients. In each event, these anomalies violated the decision rules for MPI classification and represent theoretically impossible profiles. The ratings for anomalous profiles are not mutually exclusive, and another seven patients were rated as anomalous by the scoring program, for unknown reasons. Although it would have been desirable to explore statistically the profiles of the patients who were coded as anomalous for unknown reasons, this was not possible given the small sample size. To examine the reasons for this low rate of classification, interscale Pearson correlations were computed and compared with intercor-
Vol. 7 No. 8 Nimmber 1992
relations derived from a heterogeneous chronic pain sample in the development of the MPI (see Table 3). As can be seen, the pattern of scale intercorrelation observed in the CP sample was quite different from the pattern noted in the original validation sample. For example, there was no correlation between pain severity and social activity level (T = -0.10, NS), unlike the significant correlation observed in the original validation sample (r = -0.27). However, interference from pain correlated significantly with affective distress (r= 0.37, P< 0.05) in the CP sample, unlike the nonsignificant ccrrelation (r = 0.06) observed in the validation sample. Overall, of 19 significant interscale correlations, only seven were similar in direction and in magnitude with the patterns observed in the original validation of the MPI. Given that the MPI taxonomy system was derived from the variance-covariance matrices of the MPI subscales with the original validation sample, the differences in interscale correlation noted with the CP sample indicate that the taxonomy is not appropriate for this patient group.
The purpose of this investigation was to extend the range of the MPI to include patients with chronic, nonorganic chest pain. Our results indicate that MPI scale scores for the CP patient sample more closely resemble values obtained from TMD patients than those from lower back pain patients. However, when the MPI taxonomy system was applied to this sample of nonorganic chest pdn patients, only 34.8% of the sample was abie to be cIassified into existing profiles. Comparison of the interscale correlations with those derived during the development of the MPI indicate a markedly different pattern, suggesting differences in the cognitive-behavioral nature of pain in nonorganic chest pain and rendering the empirically derived taxonomy inappropriate for use with these pain patients. This investigation is the first to compare pain profiles of nonorganic chest pain patients with other chronic pain patients. Relative to low back pain patients, CP patients had significantly lower levels of pain
cm
Sl Sl s2 s3 s4 s5 S6" s7a S8Q s9 SlO Sll s12
S2
$3
S4
s5
S6
57
S8
le S9
@-I S1Q -
s11
0.58 (0.09) -0.16 -0.15 (0.58) (0.05) 0.28 0.37 -0.52 (-0.15) (8.06) (-aAS) -0.13 -0.02 0.59 -0.35 (0.26) (-0.03) (0.34) (-0.52) 0.38 0.39 -0.29 0.26 -0.28 (0.00) (-0.38) (0.03) (-0.14) (0.20) -0.05 0.03 0.65 -0.18 0.75 -0.21 (0.34) (0.56) (0.31) (-0.08) (0.04) (-0.29) 0.20 0.17 0.43 -0.08 0.41 0.07 0.52 (0.10) (0.42) (0.05) (0.11) (-G.01)(-0.24) (8.49) 0.02 -0.01 0.25 -0.07 -0.03 -0.27 0.10 -0.06 (-0.27)(-0.31) (-0.25) (0.16) (-0.21) (0.17) (-O.31) (-0.17) -0.43 -0.39 Q.Gt? -0.17 0.18 -0.23 0.08 0.00 -0.06 (-0.10) (0.08) (-G.18)(-0.04) (0.03) (0.14) (-0.15) (0.01) (0.12) -0.04 -0.12 0.11 -8.13 0.28 -O.18 0.20 0.43 0.21 (-0.29)(=&05) (-0.19) (0.19) (-0.20)(-0.91)(-0.10) (-0.07) (0.27) a.10 -0.22 0.12 -0.43 0.13 -0.19 0.09 0.11 0.26 (-0.27) (0.04) (-0.02)(-0.31) (-O.11) (0.03) (0.08) (0.19) (0.23)
0.34 (0.31) 0.32 0.52 (O.05) (0.49)
Now ForN= 43,values It0.30, PC 0.05; for N= 35, +values i 0.33, PC 0.05; andfor original validation sample, rvahtes k 0.20, PC: iJ.05. Worrelations computed with N= 36, owing to 7 cases without a significant other (otherwise, N= 43).
severity, less interference from pain, less affective distress, and greater perceived support from significant others. This suggests that the nonorganic chest pain patients are less affected by #theirpain symptoms, relative to the low back pain sample. In many respects, the pain profiles observed in the Cl? sample resembled those of the TMD sample. In interpreting these comparisons, the fact that the low back pain group reported a markedly longer duration of pain relative tu the other two patient groups may be relevant. In particular, the extent of interference from pain and behavioral t-estriction (Section III) may be influenced by pain duration, in addition to pain site. Clinical application of the MPI would be assisted by examining the impact of pain duration on MPI profile scores. In considering the similarities observed between the TMD and CP samples, it is notable that the MPI taxonomy performs well with T&ID patients, in contrast to the present data. For example, Rudy and colleagueslo reported that only 6% of an patients could independent sample of
not be classified with the MPI taxonomy, us, although and CP patients respect to mean scale between these two mini& when multivariate profile classification is involved. This rices in the variance parameI in these two chronic pain patient samples. Possibly, the intermittent nature of both nonorganic chest pain and temporomandibular pain accounts for similarity in pain severity, lessened interference from pain, and greater behavioral activity in a number of domains. However, important dimensions of difference appear salient in this patient contrast, as evidenced by the strikingly dissimilar rates of classiflcatian. Several methodologis issues are relevant in considering these data. First, the size of the CP sample employed in this study was smaller than the sample sizes that comprised the two comparison groups. As a result, the norms provided here may not be stable and need to nt sambe replicated in a larger, indepe pattern ple of CP patients. Additionally, of interscale correlations noted from the CP
476
Beck et al.
patient data may not be stable, given the small sample size. To derive a useful taxorromy of pain profiles for CP patients, continued use of this instrument with these patients is warranted. Further research also may benefit from consideration of the influence of social desirability on MPI scale responses. As noted above, the majority (69.8%) of the CP sample was female. Further consideration of the importance of gender differences in MPI profiles awaits a larger sample of CP patients. Despite these methodologic caveats, it is notable that the MPI taxonomy system performed poorly with this sample. A constraint of this classification system is the necessity for patients to be involved in an ongoing relationship or marriage. Thus, ‘7 members of our sample could not be classified owing to the fact that they were without a significant other (e.g., spouse, intimate friend, or best friend). Although this is unusual, it has been documented that patients with nonorganic chest pain often carry comorbid psychiatric diagnoses, particularly depressive and anxiety disorders. ll~* Prospective longitudinal studies have documented the fact that over time, some percentage of these patients lose occupational functioning and withdraw se cially.1g*20Thus, this aspect of the CP sample utilized here is neither unusual nor atypical of this patient population. Adaptation of the MPI to accomodate those patients who are severely socially withdrawn appears necessary. In a different vein, the pattern of interscale correlation observed in the CP sample was sufficiently different from that derived with the original validation sample to account for this low classification rate. This correlational structure suggests important features of the cognitiv&ehavioral nature of chronic chest pain. As noted in Table 3, a significant positive correlation was noted between pain severity and pain interference, suggesting overlap in the assessment of these two pain dimensions in CP patients. A significant positive correlation was noted between interference and affective distress, indicating that the degree of impairment from episodic bouts of chest pain corresponds with greater emotional disturbance in these patients. As observed in the validation sample, a signig-
VOL7 No. 8 November 6992
cant negative correlation was noted between social activity level and affective distress. However, a nonsignificant correlation was noted between social activities and pain severity, suggesting that behavioral impairment does not necessarily correspond with greater levels of pain. Additionally, a low ( r = 0.16) correlation was observed between pain severity and perceptions of lie control, indicating that unlike other samples of chronic pain patients, CP patients do not report increased feelings of helplessness with more severe levels of pain. It is possible that the episodic nature of chest pain accounts for this correlation pattern, as the majority of the sample indicated that when symptoms occur, the duration of pain is often less than 12 hr. In particular, nonorganic chest pain often occurs suddenly and is described as “coming from out of the blue,” without provocation from exertion or exercise. Daily symptom occurrence is unusual and most patients report extended symptom-free intervals.** Thus, unlike other forms of chronic pain, nonorganic chest pain appears to be described by different cognitive-behavioral features. It is notable that related investigations have provided some degree of independent validation for the three pain profiles that comprise the MPI taxonomy. For example, Etscheidt and Braver-man*’ found support for these profiles, using the MMPI, although 25% of these authors’ sample was not able to be classified with the MPI, owing to similar reasons as noted in Takle 2. Thus, it appears that the unusually high 95% classification rate reported in Turk and Rudy’s9 replication sample may not be able to be reproduced in other samples of chronic pain patients. In summary, this paper reports scale scores for a sample of 43 patients with nonorganic chest pain, using the MPI. Nonorganic chest pain patients appear less handicapped by pain, relative to low back pain patients, although they indicate moderate pain severity and affective distress resulting from pain symptoms. Continued examination of pain profiles in patients with chronic, nonorganic chest pain appears warranted, particularly given long-standing confusion in the diagnosis and management of these patients,*0 MPI appears to be a useful instrument for
Ir,! 7 No. 8 Novder
I9542
Nmwganic Chest Pain
~sycb~~~~cal assessment data. choll988;56:233-238.
477
Consult Chn
psy-
, TurlrDC, Zaki , Curtin K’.An empirical Qxometric alternative to classification of temporo mandibular disorders. Pain 1989;36:31 l-326. Il.
itman BD, Basha chest p 147:1548-1552. Flaker G, DeRosear k, P depression in CardioL without coronary artery disease and with panic disorder. J Affective Disord 1987;13:51-59.
meters of chronic pain and valua’slr for under syxndromes 0f chronic chest pain patients.
13. Beck Be&ford MA, Taegtrrneyer A. Panic ptoms in chest pain with artery disease: a comparison with panic disorder. Bebav Ther 1990;21:211-252.
dbya adon,
nett : an fw-
1. Fordyce WE. Behavioral methods in chronic pain and illness, St Iouisz CV Mosby, 1976. 2. Eeefe FJ. Behavioral assessment and treatment of chronic pain. j Consult Clin Psycho1 1982;50:896911. ichenbaum D, Genest 3. Turk DC, behavioral m tine: a cognitive behavi tive. New York: Guilford, 1983.
2Ild
pec-
4. Turk DC, Rudy TE, Boucek CD. The contribution of psychological factors to the experience of chronic pain. In: War-fieldCA., ed. Manual of pain management. Philadelphia: JB Lippincott, 1992 (in press). , Ziter RE, Ahem DIL Failure in the 5. Follick operant treatment of chronic pain. In: Foa EB, Emmelkamp P, eds. Failures in behavior therapy, New York John Wiley, 1985.197-223. 6. Fred&son I_W,Lynd R8, RosJ. Methodology in the measurement of pain. Behav Ther 1979;9:486488. 7. Williams R Toward a set of reliable and valid measures for chronic pain assessment and outcome research. Pain 1988;35:239-251. 8. Rerns RD, Turk DC, Rudy TE. The West IiavenYale Multidimensional Pain Inventory (WI-IYMPI). Pain 1985;25:345-356. 9. Turk DC, Rudy TE. Toward an empirically derived taxonomy of chronic pain patients: integration of
rosclerotic coronary beat-t disease: arks, methods of study, and clinical features, differential diagnosis, and clinical spectrum. In: Hurst JW, ed. The heart, arteries, and veins. New York McGraw-Hill,1990:961-1001. 16. Rudy TE. Muhiaxial assessment of pain: muhidimensional pain inventory [Computer program manual]. Pittsburgh: University of Pittsburgh Medical Center, 1989. 17. Rehm LB. A selfcontrol model of depression. Behav Ther 1977;8:787-804. Confidence intervals for multiple comparisons and the misuse of the Bonferroni inequality. BrJ Math Stat Psycho1 1973;26:5=0. 19. Ockene IS, Shay MJ, Alpert JS, Weiner BH, &fen JE. UnexpGned chest pain in patients with normal coronary arteriograms. N Engl J 1249-11252. 20. Paarernak RC, Thibault GE, Savob M, D&n& RW, Hutter AM. Chest pain with angiographically insignificant coronary arterial obstruction. Am J Med 1980:813-817. 21. Etscheidt M, Braverman B. Further validation of the multidimensional pain inventory using the MMPI. Paper presented at the annual convention of the Association for the Advancement of Behavior Therapy, San Francisco, CA, 1990. 22. Wooley CF. From irritable heart to mitral valve prolapse: British army medical reports, 1860 to 1870. Am-J Cardio11985:55:1107-1109.
