Fain, 49 (1992) 71-75 0 1992 Elsevier Science
71 Publishers
B.V. All rights reserved
0304-3959/92/$0.5.00
PAIN 01983
The Chronic Illness Problem Inventory as a measure of dysfunction in chronic pain patients
Departments
Joan M. Roman0 a,c, Judith A. Turner a,b,c and Mark P. Jensen W* of ’ Psychiatry and Beharlioral Sciences and h Rehabilitation Medicine, University of Washington, Seattle,
WA 98195 (USA), and ’ Multidisciplinary Pain Center, Unicersity of Washington Medical Cenfer, Seattle, WA 98195 (USA) (Received
11 March
1991, revision
received
19 August
1991, accepted
22 August
1991)
Assessment of physical and psychosocial dysfunction is recognized as essential in chronic pain patient evaluation. One instrument, the Sickness Impact Profile (SIP), has demonstrated good reliability and validity as a measure of dysfunction among chronic pain patients. An alternate measure, the Chronic Illness Problem Inventory (CIPI), is shorter and more easily scored than the SIP, but as yet has not been applied widely to chronic pain problems. In the present study, 95 chronic low back pain patients completed the SIP, the CIPI, activity diaries, the McGill Pain Questionnaire (MPQ), and the Center for Epidemiologic Studies-Depression scale (CES-D), before participating in a chronic pain treatment study. Overt pain behaviors were also coded from videotapes of a standardized assessment protocol. Seventy-five subjects completed the measures post-treatment. The results indicate that although the SIP and the CIPI are significantly correlated and appear to be measuring similar constructs, there is also substantial unshared variance between them, suggesting that they may tap somewhat different aspects of dysfunction in chronic pain. The CIPI shows promise as a useful alternative measure of dysfunction in chronic low back pain patients, but requires further validation for this purpose. Summary
Key words: Chronic pain patients; Measurement
of dysfunction
Introduction
Chronic pain is frequently associated with significant physical and psychosocial dysfunction (Maruta and Osborne 1978; Kerns and Turk 1984; Naliboff et al. 1985; Roman0 and Turner 1985; Roy 1985). Assessment of this dysfunction is a critical part of the evaluation of chronic pain patients for clinical and research purposes (Roman0 et al. 1989). There is a need for reliable and valid measures of functional status to obtain descriptive data on patient samples in research studies, to identify problems to be addressed in treatment, and to evaluate baseline status and treatment outcome for clinical, program evaluation, and research
* Present address: Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, USA.
RJ-30,
Correspondence to: Joan M. Romano, Department of Psychiatry and Behavioral Sciences, RP-10, University of Washington, Seattle, WA 98195, USA.
purposes. One of the more widely used measures of health status is the Sickness Impact Profile (SIP) (Bergner et al. 19811. The SIP was developed as a behaviorally based measure of illness-related dysfunction applicable to a broad range of health problems. It is comprehensive in its scope, samples a wide range of areas in the physical and psychosocial domains, and has demonstrated good reliability and validity (Bergner et al. 1976a, b; Carter et al. 1976; Pollard et al. 1976; Deyo and Diehl 1983). Chronic low back pain is a particularly prevalent and disabling pain problem (Bonica 19901, and recent studies support the use of the SIP as a measure of disability in chronic low back pain patients. Results of these studies have shown that the SIP correlates significantly with other measures of dysfunction (Follick et al. 1985; Roman0 et al. 1988). However, some drawbacks associated with the use of the SIP have been noted. It is lengthy, and scoring is somewhat cumbersome. Also, although a number of studies (Turner 1982; Follick et al. 1985; Moore and Chaney 1985;
72
Roman0 et al. 1988; Turner and Clancy 1988) have found significant changes on the SIP following treatment for chronic pain problems, questions have been raised as to whether the SIP may be more sensitive in detecting deteriorating than improving dysfunction over time (Deyo and Inui 1984; Deyo and Centor 1986; MacKenzie et al. 1986). Roland and Morris (1983) developed a short (24 item) scale of self-rated disability due to back pain using items extracted from the SIP. The wording of the items was modified slightly to pertain specifically to back pain. This scale has been found to have good reliability (Roland and Morris 1983; Deyo 1986) and exhibits correlations with other measures of dysfunction comparable to those found between the physical dimension of the SIP and these other measures of dysfunction in a sample of low back pain patients (Deyo 19861. Also, the Roland scale appears to be as sensitive as the SIP in detecting change over time in this population (Deyo 1986; Deyo and Centor 1986). However, the Roland scale is weighted heavily toward the assessment of physical dysfunction, with only 3 items out of 24 taken from the psychosocial dimension of the SIP. It is not surprising then that the Roland scale has been found to correlate very highly with the physical dimension of the SIP (r = 0.89) and much more weakly with the psychosocial dimension (r = 0.59) (Deyo 1986). Thus, although the Roland scale appears to show much promise as a brief and convenient measure of back pain-related physical dysfunction, it does not appear to be a good measure of psychosocial dysfunction and has yet to be validated in samples of patients with pain problems or disability other than that related to the low back. An alternate approach to the assessment of physical and psychosocial functioning in chronically ill populations is represented by the Chronic Illness Problem Inventory (CIPI) (Kames et al. 1984). The CIPI was designed to facilitate clinical assessment of specific problems associated with chronic illness, such as physical limitations, psychosocial functioning, health care behaviors, and marital adjustment. It has about half as many items as the SIP and is more easily scored. Research on the CIPI to date suggests that it is a reliable measure and differentiates among the problems experienced by patients with varying chronic conditions, including pain, obesity, and respiratory illness (Kames et al. 1984). However, as yet there is not an extensive body of research evaluating the relative merits of the CIPI versus other functional status measures. Potentially, the CIPI might offer a viable and shorter alternative to the SIP as a measure of disability. The purpose of the present study was to compare the CIPI with the SIP as a measure of dysfunction in chronic low back pain sufferers. In particular, we evaluated (a) the extent of association between the SIP and
the CIPI before and after treatment for pain problems to determine whether these measures assess comparable constructs and behave similarly as outcome measures, and (b) the extent to which the SIP and CIPI were associated with other measures of physical and psychological dysfunction as well as self-reported pain to determine whether the SIP and CIPI exhibit similar patterns of association with these measures.
Methods Subjects Subjects were 95 chronic low back pain patients (49 females, 4h males) who participated in an outpatient pain treatment study (Turner et al. 1990). Subjects were referred by community physicians or were self-referred in response to media publicity. Patients were excluded if, in their physicians’ judgment, there were indications for further medical/surgical diagnostic or treatment procedures, or there was evidence of medical problems that would preclude participation in an active exercise program. Patients with evidence of current alcohol abuse, psychosis, or dementing illness also were excluded, as were patients who could not read and write English. All of the subjects were Caucasian, and their average age was 44 years (range = 25 to 64 years). The average time since the onset of the first back pain episode was 12.8 years (S.D. = 10 years: range = 7 months to 48 years). Ninety-one percent of patients had undergone no surgeries for back pain. Seventy-two percent-were employed full-time or part-time, and 8% were receiving financial compensation for pain.
Measures fhysicul und psychosociul disahdity. The Sickness Impact Profile (SIP) (Bergner et al. 1981) is a l&item self-report checklist assessing illness-related dysfunction in 12 categories: ambulation, mobility, body care and movement, social interaction, communication, alertness behavior. emotional behavior, sleep and rest, eating, work, home management, and recreation. In addition to I2 subscale scores, the SIP yields composite physical and psychosocial dysfunction scores as well as a total dysfunction score. The SIP was modified slightly in this study to allow ratings of pain-related rather than illness-related dysfunction. The Chronic Illness Problem Inventory (CIPI) (Kames et al. 1984) is a 65.item self-report measure assessing problems in functioning associated with chronic illness. The inventory has 19 scales: activities of daily living, inactivity, social activity, family/friends contact, employment, sleep, eating, finances, medications, cognitive, physical appearance, body deterioration, sex, assertion, medical interaction, marital overprotection, marital difficulty, and non-married relationships. Preliminary investigations support its reliability, validity, and utility across a range of chronic health problems (Kames et al. 1984). Two of the subscales (marital difficulty and marital overprotection) are assessed only in subjects who are married, and another subscale (non-married relationships) is assessed only in subjects who are single. Because all of the subjects in this study were married, the non-married relationships scale was not examined. Depression. The Center for Epidemiologic Studies-Depression scale (CES-D) (Radloff 1977) is a 20-item self-report measure yielding a numerical estimate of depression severity. It has been used widely in community studies of depression and has been demonstrated to have adequate reliability and validity (Radloff 1977). Puin reporr. The McGill Pain Questionnaire (MPQ) (Melzack 197.5) is a commonly used measure of pain. It is composed of a set of descriptors from which patients are asked to select those that most
73 accurately describe their pain experience. An overall score (the Pain Rating Index or PRI) was calculated to reflect severity of pain. There is substantial evidence supporting the reliability and validity of the MPQ (Syrjala and Chapman 1984). Activity measures. Patients completed daily activity diaries (Fordyce 1976) for 1 week. On the diaries, they indicated the amount of time spent sitting, standing or walking, and reclining. The use of diaries has demonstrated validity for measuring patient activity level (Follick et al. 1985). Time spent reclining (average number of hours per day) was chosen as the measure of activity because sitting and standing time may vary with the type of job subjects hold. It is difficult to determine, for example, if sitting time indicates disability-related rest or working at a desk. Excessive reclining is more likely to represent disability. Overtpain behaciors. Using the protocol developed by Keefe and Block (1982), patients were videotaped while sitting, standing, walking, and reclining for a total of 10 min (cf., Keefe et al. 1987, for a detailed description of this protocol). The order of these positions was varied randomly across subjects, but all subjects spent the same amount of time in each position. Videotapes were scored for guarding, bracing, rubbing, grimacing, and sighing behaviors using the coding system described by Keefe and Block (1982). The total frequency of these pain behaviors was used in data analyses. The tapes of 51 subjects (33 from pretreatment assessments and 18 from the post-treatment assessments, or 28% of available records) were randomly selected to be coded independently by two raters. Interobserver agreement was assessed by calculating coefficient kappa (Cohen 1960) for total pain behaviors and equaled 0.85.
Procedure Subjects completed all measures after screening to ensure they met study inclusion criteria and before beginning one of four randomly assigned conditions: waiting list control, behavioral therapy, exercise, and behavioral therapy plus exercise. Waiting list as well as active treatment subjects were included because the purpose of the study was to compare two measures of functional status over time, regardless of experimental manipulations, and because all subjects could improve or deteriorate whether in active treatment or not. Seventy-five (79%) of the subjects returned completed activity diaries prior to beginning their condition. Twenty subjects dropped out of the study before completion of the S-week treatment or the end of the S-week waiting list period. The 75 remaining subjects completed the questionnaire and pain behavior observation measures again after the last treatment session or at the end of the waiting list period. Activity diaries were also completed at this time by 58 subiects.
Results Overview of analyses
Three sets of analyses were performed to compare the SIP and CIPI. First, the correlations between the two measures before and after treatment and the correlations between the pre-to-post change scores of the two measures were computed to estimate the amount of shared variance. Second, the extent to which preto-post changes in scores on one measure (the SIP or CIPI) could be explained by changes in the other was examined using two analyses of covariance, each using one measure of dysfunction as the dependent variable and the other as the covariate. Finally, the correlations of the SIP and CIPI with other pain-relevant measures
TABLE
I
MEANS AND VARIABLES
STANDARD
DEVIATIONS
OF
DEPENDENT
SIP = Sickness Impact Profile total score; CIPI = Chronic Illness Problem Inventory total score; MPQ-PRI = McGill Pain Questionnaire-pain Rating Index; CES-D = Center for Epidemiologic Studies-Depression Scale. Measure
SIP CIPI CES-D MPQ-PRI Reclining time (average h/day) Total pain behaviors
Pretreatment
Post-treatment
Mean
S.D.
Mean
S.D.
7.79 15.18 11.35 21.81
6.21 7.43 6.82 10.68
4.85 11.94 7.50 17.77
5.24 6.66 5.04 11.13
9.79 3.76
1.95 3.71
9.60 3.14
1.85 3.27
were calculated. The means and standard deviations of the measures are shown in Table I. Correlation of SIP and CIPI total scores. The total scores on the SIP and the CIPI were correlated signifi‘cantly both before (r(93) = 0.72, P < 0.001, l-tailed test) and after (r(72) = 0.62, P < 0.001, l-tailed test) treatment. In addition, pre- to post-treatment changes in the SIP and CIPI total scores were correlated significantly (r(72) = 0.46, P < 0.001; one-tailed test). Pre-to-post changes in the SIP and CIPI total scores.
The distribution of the SIP scores was highly skewed, necessitating use of a log transformation to normalize the distribution prior to further data analysis. The distribution of CIPI score was less highly skewed and so could be normalized using a square root transformation. A repeated measures analysis of covariance was then conducted on the transformed scores to examine the extent to which changes in the CIPI over time could account for similar changes in the SIP. In these analyses, the pre- and post-treatment SIP scores were used as the dependent variables (with time as the repeated measures factor), and the pre- and post-treatment CIPI scores were used as the covariates. A similar analysis was used to examine the extent to which pre- to post-treatment changes in the SIP could account for changes in the CIPI. SIP changes accounted for a significant portion of change in the CIPI (as indicated by a significant covariate effect of the SIP (t = 3.09, P < O.Ol)), but a significant time effect was still found (F (1, 69) = 4.39, P < 0.051, suggesting that a significant portion of unexplained variance in changes in CIPI scores remained after accounting for change in the SIP. Repeating this analysis to partial out changes in CIPI scores from changes in SIP scores yielded a significant covariate effect of the CIPI (t = 3.09, P < 0.01) with a significant time effect remaining (F (1, 69) = 17.34, P < 0.0011,
74 TABLE
II
CORRELATIONS BETWEEN SIP, CIPI, URES OF PAIN OR DYSFUNCTION
AND
OTHER
MEAS-
SIP = Sickness Impact Profile total score; CIPI = Chronic Illness Problem Inventory total score; MPQ-PRI = McGill Pain Questionnaire-pain Rating Index; CES-D = Center for Epidemiologic Studies-Depression Scale. Measure
MPQ-PRI Total pain behaviors Reclining time CES-D
Post-treatment
Pretreatment SIP (n = 95)
CIPI (n = 95)
SIP (n = 75)
CIPI (n = 74)
0.32 ***
0.44 * * *
0.49 * * *
0.50 * * *
0.30 * * * 0.31 *** 0.54 * * *
0.21 * 0.42 *** 0.68 ***
0.19 i1 0.35 * * 0.60 a * *
0.21 * 0.42 * * * 0.62 ***
i1 P = 0.05; * P < 0.05; ** P < 0.01, ** * P < 0.001.
suggesting that SIP changes also could not be fully explained by changes in the CIPI. Relationships between dysfunction measures and other pain-related measures. Pre- and post-, both the SIP and
the CIPI total scores were correlated significantly with the MPQ-PRI, total observed pain behaviors, self-reported daily reclining time on activity diaries, and depression (see Table II). An examination of the pattern of correlations suggests that both the SIP and the CIPI are associated with this group of pain-related measures in similar ways.
Discussion
The findings indicate that there is substantial shared variance between the SIP and CIPI in measuring dysfunction related to low back pain. In addition, the pattern of relationships evidenced between the SIP and CIPI total scores and other pain-relevant measures (such as overt pain behaviors, self-reported pain, time spent reclining, and depression) is very similar. Both of these results suggest that the SIP and CIPI are, to a large extent, measuring a similar construct. However, there was also a substantial amount of unshared variance between these measures, indicating that the SIP and CIPI may be tapping somewhat different aspects of dysfunction in this group of chronic pain patients. Moreover, a series of repeated measures analyses of covariance indicated that changes in both SIP and CIPI scores over time could be explained only partially by changes in the other. This finding indicates that changes in each measure may be influenced by different factors. One such factor may be that, as the titles of the subscales of these two measures suggest, some different areas of functioning are assessed in the SIP and CIPI, despite a large degree of overlap in the areas included in both. For example, the CIPI has subscales
reflecting medical interaction and marital overprotection which are not included in the SIP. Conversely, the SIP assesses functioning in recreation and home management, areas not included in the CIPI. One finding of interest is the decrease in the association between SIP scores and overt pain behaviors from pre- to post-treatment. This decrease was not seen in the correlation between CIPI scores and pain behaviors despite the fact that both SIP and CIPI scores were lower following treatment. One possible explanation for this finding is that the range of SIP scores was considerably smaller than that of CIPI scores following treatment, and this restriction of range (and smaller variance) may have resulted in a lower correlation between pain behaviors and the SIP. Another possibility is that treatment may have affected the relationship between pain behaviors and disability as measured by the SIP. For example, patients may have decreased functional disability despite the persistence of self-reported pain and low levels of overt pain behaviors. However, any interpretation of this result must be made with considerable caution given the fact that the changes noted were not great and were not replicated in the CIPI results. Several features of this study bear further comment. One is that the study included an observational measure of pain behavior against which to compare the measures of dysfunction, rather than completely relying on self-report measures. Overt pain behaviors have been found in prior research to be associated significantly with self-rated disability as measured by the SIP (Roman0 and Turner 1989). This result was replicated in the current study and was also found for the CIPI. Another issue which should be noted is that subjects were recruited from the community, and exhibited lower levels of disability and overt pain behaviors than would likely be seen in chronic pain patients referred to a pain clinic. This may have reduced the strength of the relationships observed between the measures of disability and other measures. Further research is needed to determine whether the results of this study characterize other samples of pain patients seen in different settings. The comparison of different measures of the same construct raises the issue of which measure is preferable for various purposes. The SIP has been much more extensively evaluated for reliability, validity, and use as an outcome measure, and, therefore, is likely at present to be preferred to the CIPI as a research instrument. Conversely, in situations where the primary concern is the description of clinically relevant problems, and time available for completing questionnaires is limited (as in most clinical settings), the CIPI might be preferable. Clinicians can easily scan this brief measure to determine areas of perceived physical and psychosocial dysfunction in individual cases. Also, the
75
CIPI allows for graded responses to items on a 5-point
scale, with response options ranging from 0 (‘not at all’) to 4 (‘very much’), whereas SIP responses are dichotomous (patients simply check items that apply to them). The graded responses of the CIPI may allow the clinician to obtain a rapid estimate of the perceived severity as well as presence of a problem. In summary, the present findings provide preliminary support for the utility of the CIPI as a measure of dysfunction in mildly disabled low back pain patients. In its favor are its strong relationship to another validated measure of dysfunction (the SIP) and its ease of administration and scoring. At present, however, the psychometric properties of the CIPI have not been examined as extensively as have those of the SIP. Further work is needed to establish the CIPI’s validity in measuring pain-related physical and psychosocial dysfunction and in determining its factor structure. At present, 19 subscales are scored on the basis of item content. This large number of scale scores is unwieldy for purposes of statistical analysis in research. Factor analytic studies may be useful in identifying a smaller number of relatively independent and stable subscales for clinical and research use. References Bergner, M., Bobbitt, R.A., Kressel, S., Pollard, W.E., Gilson, B.S. and Morris, J.R., The Sickness Impact Profile: conceptual formulation and methodology for the development of a health status measure, Int. J. Hlth Serv., 6 (1976a) 393-415. Bergner, M., Bobbitt, R.A., Pollard, W.E., Martin, D.P. and Gilson, B.S., The Sickness Impact Profile: validation of a health status measure, Med. Care, 14 (1976b) 57-67. Bergner, M., Bobbitt, R.A., Carter, W.B. and Gilson, B.S., The Sickness Impact Profile: development and final revision of a health status measure, Med. Care 19 (19811 787-805. Bonica, J.J., General considerations of pain in the low back, hips, and lower extremities. In: J.J. Bonica (Ed.), The Management of Pain, 2nd edn., Vol. 2, Lea and Febiger, Philadelphia, PA, 1990, pp. 1395-1447. Carter, W.B., Bobbitt, R.A., Bergner, M. and Gilson, B.J., The validation of an interval scaling: the Sickness Impact Profile, Hlth Serv. Res., 11 1976) 516-518. Cohen, J., A coefficient of agreement for nominal scales, Educ. Psychol. Meas., 20 (1960) 37-46. Deyo, R.A., Comparative validity of the Sickness Impact Profile and shorter scales for functional assessment in low-back pain, Spine, 2 (1986) 951-954. Deyo, R.A. and Centor, R.M., Assessing the responsiveness of functional scales to clinical change: an analogy to diagnostic test performance, J. Chron. Dis., 39 (1986) 897-906. Deyo, R.A. and Diehl, A.K., Measuring physical and psychosocial function in patients with low-back pain, Spine, 8 (1983) 635-642. Deyo, R.A. and Inui, T.S., Toward clinical applications of health status measures: sensitivity of scales to clinically important changes, Hlth Serv. Res. 19 (1984) 27.5-289. Follick, M.J., Smith, T.W. and Ahern, D.K., The Sickness Impact Profile: a global measure of disability in chronic low back pain, Pain, 21 (1985) 67-76.
Fordyce, W.E., Behavioral methods for chronic pain and illness, C.V. Mosby, St. Louis 1976, 236 pp. Kames, L.D., Naliboff, B.D., Heinrich, R.L. and Schag, C.C., The Chronic Illness Problem Inventory: problem-oriented psychosocial assessment of patients with chronic illness, Int. J. Psychiat. Med., 14 (1984) 65-75. Keefe, F.J. and Block, A.R., Development of an observation method for assessing pain behavior in chronic low back pain patients, Behav. Ther., 13 (1982) 363-375. Keefe, F.J., Crisson, J.E. and Trainor, M.T., Observational methods for assessing pain: a practical guide. In: J.A. Blumenthal and D.C. McKee (Eds.), Applications in Behavioral Medicine and Health Psychology: A Clinician’s Source Book, Professional Resource Exchange, Sarasota, FL, 1987, pp. 67-94. Kerns, R.D. and Turk, P.D., Depression and chronic pain: the mediating role of the spouse, J. Marriage Fam., 46 (1984) 845-852. MacKenzie, C.R., Charlson, M.E., DiGioia. D. and KeIley, K., Can the Sickness Impact Profile measure change? An example of scale assessment, J. Chron. Dis., 39 (1986) 429-438. Maruta, T. and Osborne, D., Sexual activity in chronic pain patients, Psychosomatics, 17 (1978) 531-537. Melzack, R., The McGill Pain Questionnaire: major properties and scoring methods, Pain, 1 (1975) 277-299. Moore, J.E. and Chaney, E.F., Outpatient group treatment of chronic pain: effects of spouse involvement, J. Consult. Clin. Psychol., 53 (1985) 326-334. Naliboff, B.D., Cohen, M.J., Swanson, G.A., Bonebakker, A.D. and McArthur, D.L., Comprehensive assessment of chronic low back pain patients and controls: physical abilities, level of activity, psychological adjustment and pain perception, Pain, 23 (1985) 121-134. Pollard, W.E., Bobbitt, R.A.. Bergner, M., Martin, D.P. and Gilson, B.S., The Sickness Impact Profile: reliability of a health status measure, Med. Care, 14 (1976) 146-155. Radloff, L., The CES-D Scale: A self-report depression scale for research in the general population, Appl. Psychol. Meas., 1 (1977) 385-401. Roland, M. and Morris, R., A study of the natural history of back pain. Part I. Development of a reliable and sensitive measure of disability in low-back pain, Spine, 8 (1983) 141-144. Romano, J., Syrjala, K., Levy, R., Turner, J., Evans, P. and Keefe, F., Overt pain behaviors: relationship to patient functioning and treatment outcome, Behav. Ther. 19 (1988) 191-266. Romano, J.M. and Turner, J.A., Chronic pain and depression: does the evidence support a relationship?, Psychol. Bull., 97 (1985) 18-34. Romano, J.M., Turner, J.A. and Moore, J.E., Psychological evaluation of the chronic pain patient. In: C.D. Tollison (Ed.), Handbook of Chronic Pain Management, Williams and Wilkins, Baltimore, MD, 1989, pp. 38-51. Roy, R., Chronic pain and marital difficulties, Hlth Sot. Work., 10 (1985) 199-207. Syrjala, K.L. and Chapman, C.R., Measurement of clinical pain: a review and integration of research findings. In: C. Benedetti, CR. Chapman and G. Moricca (Eds.), Advances in Pain Research and Therapy: Recent Advances in the Management of Pain, Vol. 7, Raven Press, New York, 1984, pp. 257-296. Turner, J., Comparison of group progressive-relaxation training and cognitive-behavioral group therapy for chronic low back pain, J. Consult. Clin. Psychol., 50 (1982) 757-765. Turner, J.A. and Clancy, S.L., Comparison of operant behavioral and cognitive-behavioral group treatment for chronic low back pain, J. Consult. Clin. Psychol., 56 (1988) 261-266. Turner, J.A., Clancy, S., McQuade, K.J. and Cardenas, D.D., Effectiveness of behavioral therapy for chronic low back pain: a component analysis, J. Consult. Clin. Psychol., 58 (1990) 573-579.
71 Publishers
B.V. All rights reserved
0304-3959/92/$0.5.00
PAIN 01983
The Chronic Illness Problem Inventory as a measure of dysfunction in chronic pain patients
Departments
Joan M. Roman0 a,c, Judith A. Turner a,b,c and Mark P. Jensen W* of ’ Psychiatry and Beharlioral Sciences and h Rehabilitation Medicine, University of Washington, Seattle,
WA 98195 (USA), and ’ Multidisciplinary Pain Center, Unicersity of Washington Medical Cenfer, Seattle, WA 98195 (USA) (Received
11 March
1991, revision
received
19 August
1991, accepted
22 August
1991)
Assessment of physical and psychosocial dysfunction is recognized as essential in chronic pain patient evaluation. One instrument, the Sickness Impact Profile (SIP), has demonstrated good reliability and validity as a measure of dysfunction among chronic pain patients. An alternate measure, the Chronic Illness Problem Inventory (CIPI), is shorter and more easily scored than the SIP, but as yet has not been applied widely to chronic pain problems. In the present study, 95 chronic low back pain patients completed the SIP, the CIPI, activity diaries, the McGill Pain Questionnaire (MPQ), and the Center for Epidemiologic Studies-Depression scale (CES-D), before participating in a chronic pain treatment study. Overt pain behaviors were also coded from videotapes of a standardized assessment protocol. Seventy-five subjects completed the measures post-treatment. The results indicate that although the SIP and the CIPI are significantly correlated and appear to be measuring similar constructs, there is also substantial unshared variance between them, suggesting that they may tap somewhat different aspects of dysfunction in chronic pain. The CIPI shows promise as a useful alternative measure of dysfunction in chronic low back pain patients, but requires further validation for this purpose. Summary
Key words: Chronic pain patients; Measurement
of dysfunction
Introduction
Chronic pain is frequently associated with significant physical and psychosocial dysfunction (Maruta and Osborne 1978; Kerns and Turk 1984; Naliboff et al. 1985; Roman0 and Turner 1985; Roy 1985). Assessment of this dysfunction is a critical part of the evaluation of chronic pain patients for clinical and research purposes (Roman0 et al. 1989). There is a need for reliable and valid measures of functional status to obtain descriptive data on patient samples in research studies, to identify problems to be addressed in treatment, and to evaluate baseline status and treatment outcome for clinical, program evaluation, and research
* Present address: Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, USA.
RJ-30,
Correspondence to: Joan M. Romano, Department of Psychiatry and Behavioral Sciences, RP-10, University of Washington, Seattle, WA 98195, USA.
purposes. One of the more widely used measures of health status is the Sickness Impact Profile (SIP) (Bergner et al. 19811. The SIP was developed as a behaviorally based measure of illness-related dysfunction applicable to a broad range of health problems. It is comprehensive in its scope, samples a wide range of areas in the physical and psychosocial domains, and has demonstrated good reliability and validity (Bergner et al. 1976a, b; Carter et al. 1976; Pollard et al. 1976; Deyo and Diehl 1983). Chronic low back pain is a particularly prevalent and disabling pain problem (Bonica 19901, and recent studies support the use of the SIP as a measure of disability in chronic low back pain patients. Results of these studies have shown that the SIP correlates significantly with other measures of dysfunction (Follick et al. 1985; Roman0 et al. 1988). However, some drawbacks associated with the use of the SIP have been noted. It is lengthy, and scoring is somewhat cumbersome. Also, although a number of studies (Turner 1982; Follick et al. 1985; Moore and Chaney 1985;
72
Roman0 et al. 1988; Turner and Clancy 1988) have found significant changes on the SIP following treatment for chronic pain problems, questions have been raised as to whether the SIP may be more sensitive in detecting deteriorating than improving dysfunction over time (Deyo and Inui 1984; Deyo and Centor 1986; MacKenzie et al. 1986). Roland and Morris (1983) developed a short (24 item) scale of self-rated disability due to back pain using items extracted from the SIP. The wording of the items was modified slightly to pertain specifically to back pain. This scale has been found to have good reliability (Roland and Morris 1983; Deyo 1986) and exhibits correlations with other measures of dysfunction comparable to those found between the physical dimension of the SIP and these other measures of dysfunction in a sample of low back pain patients (Deyo 19861. Also, the Roland scale appears to be as sensitive as the SIP in detecting change over time in this population (Deyo 1986; Deyo and Centor 1986). However, the Roland scale is weighted heavily toward the assessment of physical dysfunction, with only 3 items out of 24 taken from the psychosocial dimension of the SIP. It is not surprising then that the Roland scale has been found to correlate very highly with the physical dimension of the SIP (r = 0.89) and much more weakly with the psychosocial dimension (r = 0.59) (Deyo 1986). Thus, although the Roland scale appears to show much promise as a brief and convenient measure of back pain-related physical dysfunction, it does not appear to be a good measure of psychosocial dysfunction and has yet to be validated in samples of patients with pain problems or disability other than that related to the low back. An alternate approach to the assessment of physical and psychosocial functioning in chronically ill populations is represented by the Chronic Illness Problem Inventory (CIPI) (Kames et al. 1984). The CIPI was designed to facilitate clinical assessment of specific problems associated with chronic illness, such as physical limitations, psychosocial functioning, health care behaviors, and marital adjustment. It has about half as many items as the SIP and is more easily scored. Research on the CIPI to date suggests that it is a reliable measure and differentiates among the problems experienced by patients with varying chronic conditions, including pain, obesity, and respiratory illness (Kames et al. 1984). However, as yet there is not an extensive body of research evaluating the relative merits of the CIPI versus other functional status measures. Potentially, the CIPI might offer a viable and shorter alternative to the SIP as a measure of disability. The purpose of the present study was to compare the CIPI with the SIP as a measure of dysfunction in chronic low back pain sufferers. In particular, we evaluated (a) the extent of association between the SIP and
the CIPI before and after treatment for pain problems to determine whether these measures assess comparable constructs and behave similarly as outcome measures, and (b) the extent to which the SIP and CIPI were associated with other measures of physical and psychological dysfunction as well as self-reported pain to determine whether the SIP and CIPI exhibit similar patterns of association with these measures.
Methods Subjects Subjects were 95 chronic low back pain patients (49 females, 4h males) who participated in an outpatient pain treatment study (Turner et al. 1990). Subjects were referred by community physicians or were self-referred in response to media publicity. Patients were excluded if, in their physicians’ judgment, there were indications for further medical/surgical diagnostic or treatment procedures, or there was evidence of medical problems that would preclude participation in an active exercise program. Patients with evidence of current alcohol abuse, psychosis, or dementing illness also were excluded, as were patients who could not read and write English. All of the subjects were Caucasian, and their average age was 44 years (range = 25 to 64 years). The average time since the onset of the first back pain episode was 12.8 years (S.D. = 10 years: range = 7 months to 48 years). Ninety-one percent of patients had undergone no surgeries for back pain. Seventy-two percent-were employed full-time or part-time, and 8% were receiving financial compensation for pain.
Measures fhysicul und psychosociul disahdity. The Sickness Impact Profile (SIP) (Bergner et al. 1981) is a l&item self-report checklist assessing illness-related dysfunction in 12 categories: ambulation, mobility, body care and movement, social interaction, communication, alertness behavior. emotional behavior, sleep and rest, eating, work, home management, and recreation. In addition to I2 subscale scores, the SIP yields composite physical and psychosocial dysfunction scores as well as a total dysfunction score. The SIP was modified slightly in this study to allow ratings of pain-related rather than illness-related dysfunction. The Chronic Illness Problem Inventory (CIPI) (Kames et al. 1984) is a 65.item self-report measure assessing problems in functioning associated with chronic illness. The inventory has 19 scales: activities of daily living, inactivity, social activity, family/friends contact, employment, sleep, eating, finances, medications, cognitive, physical appearance, body deterioration, sex, assertion, medical interaction, marital overprotection, marital difficulty, and non-married relationships. Preliminary investigations support its reliability, validity, and utility across a range of chronic health problems (Kames et al. 1984). Two of the subscales (marital difficulty and marital overprotection) are assessed only in subjects who are married, and another subscale (non-married relationships) is assessed only in subjects who are single. Because all of the subjects in this study were married, the non-married relationships scale was not examined. Depression. The Center for Epidemiologic Studies-Depression scale (CES-D) (Radloff 1977) is a 20-item self-report measure yielding a numerical estimate of depression severity. It has been used widely in community studies of depression and has been demonstrated to have adequate reliability and validity (Radloff 1977). Puin reporr. The McGill Pain Questionnaire (MPQ) (Melzack 197.5) is a commonly used measure of pain. It is composed of a set of descriptors from which patients are asked to select those that most
73 accurately describe their pain experience. An overall score (the Pain Rating Index or PRI) was calculated to reflect severity of pain. There is substantial evidence supporting the reliability and validity of the MPQ (Syrjala and Chapman 1984). Activity measures. Patients completed daily activity diaries (Fordyce 1976) for 1 week. On the diaries, they indicated the amount of time spent sitting, standing or walking, and reclining. The use of diaries has demonstrated validity for measuring patient activity level (Follick et al. 1985). Time spent reclining (average number of hours per day) was chosen as the measure of activity because sitting and standing time may vary with the type of job subjects hold. It is difficult to determine, for example, if sitting time indicates disability-related rest or working at a desk. Excessive reclining is more likely to represent disability. Overtpain behaciors. Using the protocol developed by Keefe and Block (1982), patients were videotaped while sitting, standing, walking, and reclining for a total of 10 min (cf., Keefe et al. 1987, for a detailed description of this protocol). The order of these positions was varied randomly across subjects, but all subjects spent the same amount of time in each position. Videotapes were scored for guarding, bracing, rubbing, grimacing, and sighing behaviors using the coding system described by Keefe and Block (1982). The total frequency of these pain behaviors was used in data analyses. The tapes of 51 subjects (33 from pretreatment assessments and 18 from the post-treatment assessments, or 28% of available records) were randomly selected to be coded independently by two raters. Interobserver agreement was assessed by calculating coefficient kappa (Cohen 1960) for total pain behaviors and equaled 0.85.
Procedure Subjects completed all measures after screening to ensure they met study inclusion criteria and before beginning one of four randomly assigned conditions: waiting list control, behavioral therapy, exercise, and behavioral therapy plus exercise. Waiting list as well as active treatment subjects were included because the purpose of the study was to compare two measures of functional status over time, regardless of experimental manipulations, and because all subjects could improve or deteriorate whether in active treatment or not. Seventy-five (79%) of the subjects returned completed activity diaries prior to beginning their condition. Twenty subjects dropped out of the study before completion of the S-week treatment or the end of the S-week waiting list period. The 75 remaining subjects completed the questionnaire and pain behavior observation measures again after the last treatment session or at the end of the waiting list period. Activity diaries were also completed at this time by 58 subiects.
Results Overview of analyses
Three sets of analyses were performed to compare the SIP and CIPI. First, the correlations between the two measures before and after treatment and the correlations between the pre-to-post change scores of the two measures were computed to estimate the amount of shared variance. Second, the extent to which preto-post changes in scores on one measure (the SIP or CIPI) could be explained by changes in the other was examined using two analyses of covariance, each using one measure of dysfunction as the dependent variable and the other as the covariate. Finally, the correlations of the SIP and CIPI with other pain-relevant measures
TABLE
I
MEANS AND VARIABLES
STANDARD
DEVIATIONS
OF
DEPENDENT
SIP = Sickness Impact Profile total score; CIPI = Chronic Illness Problem Inventory total score; MPQ-PRI = McGill Pain Questionnaire-pain Rating Index; CES-D = Center for Epidemiologic Studies-Depression Scale. Measure
SIP CIPI CES-D MPQ-PRI Reclining time (average h/day) Total pain behaviors
Pretreatment
Post-treatment
Mean
S.D.
Mean
S.D.
7.79 15.18 11.35 21.81
6.21 7.43 6.82 10.68
4.85 11.94 7.50 17.77
5.24 6.66 5.04 11.13
9.79 3.76
1.95 3.71
9.60 3.14
1.85 3.27
were calculated. The means and standard deviations of the measures are shown in Table I. Correlation of SIP and CIPI total scores. The total scores on the SIP and the CIPI were correlated signifi‘cantly both before (r(93) = 0.72, P < 0.001, l-tailed test) and after (r(72) = 0.62, P < 0.001, l-tailed test) treatment. In addition, pre- to post-treatment changes in the SIP and CIPI total scores were correlated significantly (r(72) = 0.46, P < 0.001; one-tailed test). Pre-to-post changes in the SIP and CIPI total scores.
The distribution of the SIP scores was highly skewed, necessitating use of a log transformation to normalize the distribution prior to further data analysis. The distribution of CIPI score was less highly skewed and so could be normalized using a square root transformation. A repeated measures analysis of covariance was then conducted on the transformed scores to examine the extent to which changes in the CIPI over time could account for similar changes in the SIP. In these analyses, the pre- and post-treatment SIP scores were used as the dependent variables (with time as the repeated measures factor), and the pre- and post-treatment CIPI scores were used as the covariates. A similar analysis was used to examine the extent to which pre- to post-treatment changes in the SIP could account for changes in the CIPI. SIP changes accounted for a significant portion of change in the CIPI (as indicated by a significant covariate effect of the SIP (t = 3.09, P < O.Ol)), but a significant time effect was still found (F (1, 69) = 4.39, P < 0.051, suggesting that a significant portion of unexplained variance in changes in CIPI scores remained after accounting for change in the SIP. Repeating this analysis to partial out changes in CIPI scores from changes in SIP scores yielded a significant covariate effect of the CIPI (t = 3.09, P < 0.01) with a significant time effect remaining (F (1, 69) = 17.34, P < 0.0011,
74 TABLE
II
CORRELATIONS BETWEEN SIP, CIPI, URES OF PAIN OR DYSFUNCTION
AND
OTHER
MEAS-
SIP = Sickness Impact Profile total score; CIPI = Chronic Illness Problem Inventory total score; MPQ-PRI = McGill Pain Questionnaire-pain Rating Index; CES-D = Center for Epidemiologic Studies-Depression Scale. Measure
MPQ-PRI Total pain behaviors Reclining time CES-D
Post-treatment
Pretreatment SIP (n = 95)
CIPI (n = 95)
SIP (n = 75)
CIPI (n = 74)
0.32 ***
0.44 * * *
0.49 * * *
0.50 * * *
0.30 * * * 0.31 *** 0.54 * * *
0.21 * 0.42 *** 0.68 ***
0.19 i1 0.35 * * 0.60 a * *
0.21 * 0.42 * * * 0.62 ***
i1 P = 0.05; * P < 0.05; ** P < 0.01, ** * P < 0.001.
suggesting that SIP changes also could not be fully explained by changes in the CIPI. Relationships between dysfunction measures and other pain-related measures. Pre- and post-, both the SIP and
the CIPI total scores were correlated significantly with the MPQ-PRI, total observed pain behaviors, self-reported daily reclining time on activity diaries, and depression (see Table II). An examination of the pattern of correlations suggests that both the SIP and the CIPI are associated with this group of pain-related measures in similar ways.
Discussion
The findings indicate that there is substantial shared variance between the SIP and CIPI in measuring dysfunction related to low back pain. In addition, the pattern of relationships evidenced between the SIP and CIPI total scores and other pain-relevant measures (such as overt pain behaviors, self-reported pain, time spent reclining, and depression) is very similar. Both of these results suggest that the SIP and CIPI are, to a large extent, measuring a similar construct. However, there was also a substantial amount of unshared variance between these measures, indicating that the SIP and CIPI may be tapping somewhat different aspects of dysfunction in this group of chronic pain patients. Moreover, a series of repeated measures analyses of covariance indicated that changes in both SIP and CIPI scores over time could be explained only partially by changes in the other. This finding indicates that changes in each measure may be influenced by different factors. One such factor may be that, as the titles of the subscales of these two measures suggest, some different areas of functioning are assessed in the SIP and CIPI, despite a large degree of overlap in the areas included in both. For example, the CIPI has subscales
reflecting medical interaction and marital overprotection which are not included in the SIP. Conversely, the SIP assesses functioning in recreation and home management, areas not included in the CIPI. One finding of interest is the decrease in the association between SIP scores and overt pain behaviors from pre- to post-treatment. This decrease was not seen in the correlation between CIPI scores and pain behaviors despite the fact that both SIP and CIPI scores were lower following treatment. One possible explanation for this finding is that the range of SIP scores was considerably smaller than that of CIPI scores following treatment, and this restriction of range (and smaller variance) may have resulted in a lower correlation between pain behaviors and the SIP. Another possibility is that treatment may have affected the relationship between pain behaviors and disability as measured by the SIP. For example, patients may have decreased functional disability despite the persistence of self-reported pain and low levels of overt pain behaviors. However, any interpretation of this result must be made with considerable caution given the fact that the changes noted were not great and were not replicated in the CIPI results. Several features of this study bear further comment. One is that the study included an observational measure of pain behavior against which to compare the measures of dysfunction, rather than completely relying on self-report measures. Overt pain behaviors have been found in prior research to be associated significantly with self-rated disability as measured by the SIP (Roman0 and Turner 1989). This result was replicated in the current study and was also found for the CIPI. Another issue which should be noted is that subjects were recruited from the community, and exhibited lower levels of disability and overt pain behaviors than would likely be seen in chronic pain patients referred to a pain clinic. This may have reduced the strength of the relationships observed between the measures of disability and other measures. Further research is needed to determine whether the results of this study characterize other samples of pain patients seen in different settings. The comparison of different measures of the same construct raises the issue of which measure is preferable for various purposes. The SIP has been much more extensively evaluated for reliability, validity, and use as an outcome measure, and, therefore, is likely at present to be preferred to the CIPI as a research instrument. Conversely, in situations where the primary concern is the description of clinically relevant problems, and time available for completing questionnaires is limited (as in most clinical settings), the CIPI might be preferable. Clinicians can easily scan this brief measure to determine areas of perceived physical and psychosocial dysfunction in individual cases. Also, the
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CIPI allows for graded responses to items on a 5-point
scale, with response options ranging from 0 (‘not at all’) to 4 (‘very much’), whereas SIP responses are dichotomous (patients simply check items that apply to them). The graded responses of the CIPI may allow the clinician to obtain a rapid estimate of the perceived severity as well as presence of a problem. In summary, the present findings provide preliminary support for the utility of the CIPI as a measure of dysfunction in mildly disabled low back pain patients. In its favor are its strong relationship to another validated measure of dysfunction (the SIP) and its ease of administration and scoring. At present, however, the psychometric properties of the CIPI have not been examined as extensively as have those of the SIP. Further work is needed to establish the CIPI’s validity in measuring pain-related physical and psychosocial dysfunction and in determining its factor structure. At present, 19 subscales are scored on the basis of item content. This large number of scale scores is unwieldy for purposes of statistical analysis in research. Factor analytic studies may be useful in identifying a smaller number of relatively independent and stable subscales for clinical and research use. References Bergner, M., Bobbitt, R.A., Kressel, S., Pollard, W.E., Gilson, B.S. and Morris, J.R., The Sickness Impact Profile: conceptual formulation and methodology for the development of a health status measure, Int. J. Hlth Serv., 6 (1976a) 393-415. Bergner, M., Bobbitt, R.A., Pollard, W.E., Martin, D.P. and Gilson, B.S., The Sickness Impact Profile: validation of a health status measure, Med. Care, 14 (1976b) 57-67. Bergner, M., Bobbitt, R.A., Carter, W.B. and Gilson, B.S., The Sickness Impact Profile: development and final revision of a health status measure, Med. Care 19 (19811 787-805. Bonica, J.J., General considerations of pain in the low back, hips, and lower extremities. In: J.J. Bonica (Ed.), The Management of Pain, 2nd edn., Vol. 2, Lea and Febiger, Philadelphia, PA, 1990, pp. 1395-1447. Carter, W.B., Bobbitt, R.A., Bergner, M. and Gilson, B.J., The validation of an interval scaling: the Sickness Impact Profile, Hlth Serv. Res., 11 1976) 516-518. Cohen, J., A coefficient of agreement for nominal scales, Educ. Psychol. Meas., 20 (1960) 37-46. Deyo, R.A., Comparative validity of the Sickness Impact Profile and shorter scales for functional assessment in low-back pain, Spine, 2 (1986) 951-954. Deyo, R.A. and Centor, R.M., Assessing the responsiveness of functional scales to clinical change: an analogy to diagnostic test performance, J. Chron. Dis., 39 (1986) 897-906. Deyo, R.A. and Diehl, A.K., Measuring physical and psychosocial function in patients with low-back pain, Spine, 8 (1983) 635-642. Deyo, R.A. and Inui, T.S., Toward clinical applications of health status measures: sensitivity of scales to clinically important changes, Hlth Serv. Res. 19 (1984) 27.5-289. Follick, M.J., Smith, T.W. and Ahern, D.K., The Sickness Impact Profile: a global measure of disability in chronic low back pain, Pain, 21 (1985) 67-76.
Fordyce, W.E., Behavioral methods for chronic pain and illness, C.V. Mosby, St. Louis 1976, 236 pp. Kames, L.D., Naliboff, B.D., Heinrich, R.L. and Schag, C.C., The Chronic Illness Problem Inventory: problem-oriented psychosocial assessment of patients with chronic illness, Int. J. Psychiat. Med., 14 (1984) 65-75. Keefe, F.J. and Block, A.R., Development of an observation method for assessing pain behavior in chronic low back pain patients, Behav. Ther., 13 (1982) 363-375. Keefe, F.J., Crisson, J.E. and Trainor, M.T., Observational methods for assessing pain: a practical guide. In: J.A. Blumenthal and D.C. McKee (Eds.), Applications in Behavioral Medicine and Health Psychology: A Clinician’s Source Book, Professional Resource Exchange, Sarasota, FL, 1987, pp. 67-94. Kerns, R.D. and Turk, P.D., Depression and chronic pain: the mediating role of the spouse, J. Marriage Fam., 46 (1984) 845-852. MacKenzie, C.R., Charlson, M.E., DiGioia. D. and KeIley, K., Can the Sickness Impact Profile measure change? An example of scale assessment, J. Chron. Dis., 39 (1986) 429-438. Maruta, T. and Osborne, D., Sexual activity in chronic pain patients, Psychosomatics, 17 (1978) 531-537. Melzack, R., The McGill Pain Questionnaire: major properties and scoring methods, Pain, 1 (1975) 277-299. Moore, J.E. and Chaney, E.F., Outpatient group treatment of chronic pain: effects of spouse involvement, J. Consult. Clin. Psychol., 53 (1985) 326-334. Naliboff, B.D., Cohen, M.J., Swanson, G.A., Bonebakker, A.D. and McArthur, D.L., Comprehensive assessment of chronic low back pain patients and controls: physical abilities, level of activity, psychological adjustment and pain perception, Pain, 23 (1985) 121-134. Pollard, W.E., Bobbitt, R.A.. Bergner, M., Martin, D.P. and Gilson, B.S., The Sickness Impact Profile: reliability of a health status measure, Med. Care, 14 (1976) 146-155. Radloff, L., The CES-D Scale: A self-report depression scale for research in the general population, Appl. Psychol. Meas., 1 (1977) 385-401. Roland, M. and Morris, R., A study of the natural history of back pain. Part I. Development of a reliable and sensitive measure of disability in low-back pain, Spine, 8 (1983) 141-144. Romano, J., Syrjala, K., Levy, R., Turner, J., Evans, P. and Keefe, F., Overt pain behaviors: relationship to patient functioning and treatment outcome, Behav. Ther. 19 (1988) 191-266. Romano, J.M. and Turner, J.A., Chronic pain and depression: does the evidence support a relationship?, Psychol. Bull., 97 (1985) 18-34. Romano, J.M., Turner, J.A. and Moore, J.E., Psychological evaluation of the chronic pain patient. In: C.D. Tollison (Ed.), Handbook of Chronic Pain Management, Williams and Wilkins, Baltimore, MD, 1989, pp. 38-51. Roy, R., Chronic pain and marital difficulties, Hlth Sot. Work., 10 (1985) 199-207. Syrjala, K.L. and Chapman, C.R., Measurement of clinical pain: a review and integration of research findings. In: C. Benedetti, CR. Chapman and G. Moricca (Eds.), Advances in Pain Research and Therapy: Recent Advances in the Management of Pain, Vol. 7, Raven Press, New York, 1984, pp. 257-296. Turner, J., Comparison of group progressive-relaxation training and cognitive-behavioral group therapy for chronic low back pain, J. Consult. Clin. Psychol., 50 (1982) 757-765. Turner, J.A. and Clancy, S.L., Comparison of operant behavioral and cognitive-behavioral group treatment for chronic low back pain, J. Consult. Clin. Psychol., 56 (1988) 261-266. Turner, J.A., Clancy, S., McQuade, K.J. and Cardenas, D.D., Effectiveness of behavioral therapy for chronic low back pain: a component analysis, J. Consult. Clin. Psychol., 58 (1990) 573-579.
