Behaa.
Res.
Thu.
Vol.
29, No.
5, pp.
443450,
0005-7967/91
1991
$3.00
+ 0.00
Copyright 0 1991Pergamon Press plc
Printed in Great Britain. All rights reserved
THE PREVENTION OF CHRONIC PAIN AND DISABILITY: A PRELIMINARY INVESTIGATION H . C . PHILIPS,~* L. GRANT’ and J. BERKOWITZ* ‘Psychology Department, University Hospital, Shaughnessy Site, Vancouver, British Columbia, Canada V6H 3Nl and ZBerkowitz & Associates, 4160 Staulo Crescent, Vancouver, British Columbia, Canada V6N 3S2 (Received 10 December
1990; received for publication 15 April 1991)
Summary-A preliminary investigation was undertaken on 117 acute back pain cases, to assess the utility of counseling at the acute stage upon the course of recovery over the subsequent 6 months. In addition, the extent to which psychological reactions to acute injury would allow the ‘tagging’ of individuals at risk for chronic pain problems, was studied. The minimal rehabilitation counseling proved inadequate to effect the course of recovery, but remarkably accurate predictions were possible at the sub-chronic point (3 months) as to who would make complete recoveries.
INTRODUCTION
With the development of multidisciplinary clinics, psychologists have been involved in developing new techniques for the management of chronic pain problems (Turk, Meichenbaum & Genest, 1983; Holtzman & Turk, 1986; Philips, 1988). Cognitive and behavioral methods have focused on reduction of pain and disability, and the teaching of management techniques that can make sufferers increasingly independent of medical services. Although the results are very encouraging, most clinics have long waiting lists and there appears to be an escalating incidence of chronic pain problems (Nachemson, 1984). Health care costs are rising, and it has been estimated that in the United States alone, over 60 billion dollars are spent per year on chronic pain problems (Bonica, 1980). With the increasing cost and size of this problem, it is clear that resources need to be focused on those people liable to develop chronic pain problems, with the aim of prevention or reduction of the size of the problem (Nachemson, 1984). If individuals could be ‘tagged’ during the acute period (within days of onset of an acute episode) resources could be directed toward these individuals. As preventive techniques evolve, total health care costs will shrink. A longitudinal study carried out by the authors (Philips & Grant, 1991) suggests that current estimates of those who are likely to develop chronic pain (lO-15% of acute back injuries, Nachemson, 1982) may be underestimates. Up to 40% of the sample studied continued reporting pain 6 months after acute episode. This suggests that there are a large number of people who continue having pain post-healing, and on whom preventive work could be focused. Currently, little attention is given to prevention. Spontaneous remission is assumed to parallel healing and no counseling is considered until pain has persisted for years. Physical treatments continue to be explored even when healing is complete. By the time pain sufferers are referred to a pain management clinic, they may have seen multiple specialists and endured pain for nearly a decade (Philips, 1987). Over the last few years there has been a trend to consider the end of the ‘acute period’ as coinciding with completion of tissue healing. The Classification of Chronic Pain (IAP: 1986) has suggested that the term ‘chronic’ be used at 3 months after the acute episode, while the Report of the Quebec Task Force (1987) on back pain has shifted it even closer to initial injury. They suggest a cut-off at 7 weeks, identifying a ‘sub-acute period’ between 7 days and 7 weeks post-onset. Some empirical support for this shift can be found in Philips and Grant, 1991. Therefore, preventive interventions would need to be undertaken in the early weeks following an acute back injury. *Author for correspondence. 443
444
H. C. F'HILIPS~~al.
Although not formulated as preventive methods, different rehabilitation approaches have been used. The traditional approach was to counsel withdrawal and avoidance of activity and encourage bedrest. This passive approach to the recovery period has been superseded by a more active one which has been described as ‘letting pain guide’. This approach encourages the patient to regulate their active reinvolvement in daily life by assessing pain levels. If pain increases, rest and withdrawal is encouraged. When pain subsides, a return to normal activity is recommended. In contrast, some physicians are now recommending graded exposure and return to activity, irrespective of pain-to begin within 72 hr of the onset of an acute pain episode. They are counseling a graduated exercise program which begins at a low level and continues daily, despite changes in pain level. Results to date have not compared these three strategies in any systematic manner. However, there is sufficient evidence of the detrimental effects of total avoidance and bedrest over long periods to have made this first rehabilitation strategy unacceptable {Deyo, Diehl & Rosenthal, 1986; Gilbert, Taylor, Hildebrand & Evans, 1985). The other two approaches need to be compared; preliminary results suggest that graded exposure may be an important way of limiting the development of chronic problems (Fordyce, Brockway, Bergman & Spengler, 1986). As yet no attempt has been made to consider to what extent counselling at the acute stage has an effect, irrespective of the type of advice given. In order to explain any rehabilitation rationale, the doctor or therapist provides an explanatory framework which may act to reduce the emotional reaction and limit avoidance behavior. The aim of the current study was to evaluate the preventive power of the two common rehabilitation approaches to acute back pain: ‘letting pain guide’ the return to normal, and graded reactivation, irrespective of pain. This study also systematically assesses the utility of early behavioral counseling in how to apply these two phiIosophies of rehabilitation, not only to exercise, but to other aspects of the person’s life. Finally, a preliminary attempt is made to ‘tag’ individuals at risk for developing chronic pain, on the basis of their reaction to acute injury. Early identification of prone individuals would allow preventive techniques to be focused on them. METHODOLOCY Subjects
117 individuals were referred to the study from Emergency Departments and general practitioners. They had reported their first onset of acute back or neck pain within 15 days of its onset and had no signs of neural or discal damage. They were each paid $75 at the completion of the last of their three sessions over a 6 month period. The payments were used as incentives to keep individuaIs involved in the study, irrespective of whether or not pain was still present. The average age was 32 yr (F7.6 yr); 42.7% were male, 57.3% were female. The initial visit occurred, on average, 7.9 days (f4.6 days) after pain onset. The second visit (subchronic) was planned for 3 months post-onset and occurred, on average, 13.7 weeks (+ 1.2 weeks) post-onset. The third visit (‘chronic’) occurred at 6 months post-onset. The attrition rate at 6 months was 21%. (This was due to Ss moving away, being unwilling to attend, being advised against it by their lawyers, or not being able to be contacted by the researchers.) This left 91 cases at 3 months, and 92 cases at 6 months. (One individual unable to attend at 3 months, was available at the 6 month point). Procedure
All Ss were contacted by phone and a visit was arranged for them in the research offices. The acute assessment lasted 45 min, entailing a structured interview (obtainable from the authors), the completion of questionnaire and the provision of rehabilitation advice. Follow-up contacts at 3 months (subchronic) and 6 months required only a 30-min structured interview (also available from the authors).
The battery of questionnaires completed at each of the three contact points consisted of: Beck Depression Inventory (Beck, Ward, Mendelson, Mock & Erbaugh, 1961), State-Trait Anxiety Inventory (Speilberger, 1983), Pain Behaviour Checklist (Philips & Jahanshahi, 1986), Pain
The prevention
of chronic
back pain
445
Evaluation Questionnarie (Philips, 1989) Sickness Impact Profile (Bergner, Bobbit, Carter & Gilson, 1981), and Pain Quality Questionnaire (Hunter, 1983). In addition, a structured interview was designed to collect information on continuation of pain, pain intensity and contingencies for exercising (i.e. pain dependent exercise or exercise irrespective of pain). Examples of the interview may be obtained from the authors. Design Ss were randomly allocated to one of two groups, defined by the rehabilitation methods used. Group A. ‘Let pain guide’ the return to normal. The aim was to return to the previous level of
functioning if pain reductions allowed. Group B. Graded and gradual reactivation approach, building back to normal functioning. Pain was not a guide to the rate of reactivation. An incremental schedule of activity was recommended. The two different rehabilitation approaches were explained and demonstrated to Ss with a set of physical exercises, appropriate to the individuals on the basis of their pain locus (upper back and neck vs middle and lower back) and fitness level. Ss allocated to Group A (let pain guide) were asked to let pain levels guide them as to which excercises to undertake and how many of each to do. Those in Group B (graded reactivation) were told to use a gradual incremental basis provided for each exercise irrespective of current pain levels. (Instructions and exercise routines obtainable from the authors.) The two groups were further divided to compare two counseling methods. Behavioral counseling provided explanations of how the rehabilitation approach was to be applied to their particular lives. It was undertaken with respect to exercise, social activities and return to work. Problem-solving was done with the individuals in order to help them see how the approach could be used over all the different areas of their life. Psychotherapy counseling (Control counseling) provided general non-directive discussion with respect to the significance of the pain episode to them and their history of previous pain experiences. No behavioral instruction was given in the control counseling. Although this allocation led to four groups (Rehabilitation Group A: Behavioral and Control counseling; Rehabilitation Group B: Behavioral and Control counseling) insufficient numbers of Ss in this preliminary study prevented a four-way group comparison. Group comparisons were made, however, between three groups, Group A: Behavioral counseling (n = 34) Group B: Behavioral counseling (n = 35) and Group B: Control counseling (n = 40). RESULTS Prevention
of chronic pain
Approximately 40% of the individuals, followed over the 6 month period, reported that they still experienced pain which they considered had started at the acute episode. Using the presence or absence of reported pain at the 6 month point as the criterion of chronic pain, no significant difference was evident between the two rehabilitation approaches. In other words, there was no suggestion that the two different policies (Let pain guide vs graded activation) had differential effects on the chronic pain process. However, a trend was evident when the groups were compared with respect to the presence or absence of behavioral advice as to how to apply the rehabilitation advice to their own lives (see Table 1). Those receiving the behavioral counseling had a higher proportion of cases with no pain, than cases with pain. This was not true for those having an equal amount of discussion with the counselor but without any behavioral instruction. Although the two approaches (Groups A and B) did not significantly influence pain courseper se, they appeared to have successfully changed exercise patterns. 86% of Group B Ss began exercising Table I. Numbers of Ss reporting chronic pain or pain-free status at 6 months in the counseling and control groups
Pain No pain Total
Control
Behavioral counseling
Total
16 17 33
23 36 59
39 53 92
446
H. C. PHILIPS
Table
et al.
2. Percentage of cases within each group who reported exercise patterns dependent presence/level, or independent of pain, at 3 and 6 month assessment points Sub-chronic Pain dependent exercise (%)
Group A (let pain guide recovery) Group B Ceraded activation)
(3 months)
Chronic
on pain
(6 months)
Exercise irrespective of pain (%)
Pain dependent exercise (%)
Exercise irrespective of pain (%)
75.9
20.0
66.0
26.0
21.4
59.0
34.0
63.0
within 3 days of their visit to the study offices. In contrast, only 55% of Group A began at this early stage. The two groups reported no difference with respect to the regularity of their exercise regime at the 3 month point, with 4&50% exercising a few times a week or more frequently. However, there was a significant difference between the groups with respect to when they exercised (x2 = 28.2, P < 0.005); this was consistent with the respective rehabilitation advice (see Table 2). Significantly more individuals in Group A (let pain guide) reported exercise depended on pain levels. The differences were still present at 6 months post-onset, suggesting a prolonged change in behavior as a result of minimal counseling with respect to the approach to be taken to exercise. However, the behavioral changes did not prevent chronic pain developing. The two rehabilitation approaches did not have any significant impact on the strong association of litigious involvement and the development of chronic pain (Philips & Grant, 1991). There is no evidence that this association was weakened either by the rehabilitation approach or by the presence or absence of psychological counseling. Unfortunately, the attrition rate differed between the groups. Where active involvement was requested (Group B), and especially where no behavioral counseling was provided to support the rehabilitation method, the drop-out rate was highest (see Table 3). Tugging
individuals at risk ,for the development
of chronic pain problems
Because of the lack of significant effect of group allocation on pain state at outcome, it was possible to combine all the individuals into one group in order to investigate the relationship of acute reaction to pain and subsequent course. Cross-sectional analyses of the data at the three time points (acute, subchronic and chronic) showed remarkably similar results at the 3 and 6 month points (cf. Philips & Grant, 1991). Consequently, the most important prediction appears to be between acute onset and subchronic status. The first 3 month period led to the following findings. (1) When the locus of acute pain was in the upper back (upper spine and/or neck), it was more likely that the pain would still be present at three months (x2 = 8.7, P < 0.02). Acute pain provoked by injury, rather than by sports accidents, overuse or spontaneous onset, was more likely to be present at the 3 month point (x2 = 24.9, P < 0.000). Individuals reporting legal involvement at the acute onset were more likely to report pain persisting at the 3 month point (x2 = 13.2, P < 0.001). Thus legal involvement, upper spine and neck pain, and ‘injury’ etiologies appear to be relevant acute characteristics with respect to pain persistence. (2) Examining the acute pain response in more detail, the sample was divided at the acute assessment into two groups defined by pain status at the subchronic stage. A simple division by Table 3. Number
of cases per group and attrition months ChOUDS
Group
Group
A:
B:
No. of cases
rate (%) at 6 Drop-outs (%)
Let pain guide counseled control
34 8
9 0
Graded activation counseled control
35 40
23 38
447
The prevention of chronic back pain Table 4. Difference between mean scores on dependent measures at the acute assessment, for two groups defined on the basis of pain status at 3 months (subchronic evaluation) Acute assessment Pain intensity (rating O-100)
Pain
Pain status at 3 months I No pain
P
43.0(8.90)
2.33
0.020
I .21 (0.57) 1.62 (0.64)
0.76 (0.46) 1.16(0.59)
4.12 3.51
0.001 0.005
Pain behavior avoidance complaint
52% (21 .O) 67% (22.0)
43% (21.0) 65% (23.0)
I .94 0.49
0.056 NS
Pain evaluation questionnaire
54.5 (23.99)
41.5 (20.51)
2.76
0.007
Pain quality sensory affective
Beck depression Inventory STAI: State Sickness Impact _ _. Profile Total score
52.1 (17.65)
10.9 (8.27) 47.74(13.35)
14.8 (10.80)
8.22 (7.14)
1.61
NS
39.62 (I 1.71)
3.05
0.003
9.3 (8.08)
2.8
0.007
presence or absence of continuing pain at 3 months was used as the criterion. Table 4 provides the mean and standard deviation of each of the dependent measures for these two groups at the acute assessment. Those at risk for continuing pain at 3 months were significantly different at the acute stage from those who recovered within a 3 month period. They reported significantly higher acute pain levels, both with respect to sensory and affective qualities. They also reported significantly more negative cognitive reactions to pain, higher anxiety, and detailed a much larger behavioral impact of the pain on their everyday lives (Sickness Impact). They were not differentiated with respect to depression, which was found to be within normal limits. A trend toward higher levels of avoidance behavior was present for those who subsequently reported pain at 3 months. Highly significant differences were found between groups at three months (defined by pain status at 6 months) on all measures, exception the Beck Depression Inventory. In contrast, tagging individuals at the acute stage with respect to their 6 month status is not as successful. Pain rated intensity and the sensory and affective component of the pain experience are significantly different, but the other variables are no longer useful predictors across this longer period of time. (3) The above analyses compared the characteristics of those who subsequently reported continuing pain with those who did not, by undertaking t-tests on the dependent variables at the acute stage. As a consequence, the group more at risk could be defined at onset by pain qualities and psychological reactions to acute injury. A more powerful method, Stepwise Logistic Regression, was also used, to evaluate the relative potency of the predictive variables. Logistic regression has weaker distributional assumptions than discriminant analysis, but is a comparable technique (Dillon & Goldstein, 1984). Logistic regression provides a classification table which gives the percentage of correctly classified cases, as well as specificity (percent correct negative), sensitivity (percent correct positive), false negatives, and false positives. Three predictions were obtained: subchronic from acute, chronic from subchronic, and chronic from acute. The effectiveness of each prediction was measured by comparison with predictions based solely on the frequency of response on the dependent variables. For example, at 6 months 57.1% of cases would be correctly classified by predicting all Ss to be pain-free. (A prediction of ‘not pain-free’ for all cases would be correct in 42.9% of the cases.) Many of the predictions are in fact markedly better than chance. There are significant and considerable improvements in predictive power especially with respect to predictions of chronic status from the three month point. (See Table 5). The best predictions of chronic status can be made at 3 months, when 80.0% can be correctly classified. Here, specificity is highest and false negatives lowest. Therefore at 3 months, correct predictions of those who will not have chronic pain can be made with remarkable accuracy (94.2% correct). Prediction of those who will have chronic problems, although better than chance, is not as accurate (60.5%). The relative predictive power of each of the dependent measures was evaluated using a backward logistic regression analysis. The sensory pain component at the acute stage could correctly classify
448
H. C. PHILIPS
et al.
Table 5. Predictions of pain status (in % correctly classified) from acute and subchronic stepwise logististic regression analysis on all of the dependent measures
% Correctly classified (using all dependent measures) (A) Specificity (correct negatives) (B) Sensitivity (correct positives) (C) False negatives (D) False oositives
responses
using
Prediction of subchronic status from acute responses
Prediction of chronic status from acute responses
Prediction of chronic status from subchronic responses
75.5
68.1
80.0
84.0
80.8
94.2
63.0
51.3
60.5
21.6 22.2
33.0 31.0
11.5 23.4
67.0% of cases with respect to their subchronic status. The other dependent measures only improve the accuracy of the prediction to 74.5%. This was due to the high intercorrelation between the measures taken at the acute point. As they are all measures of aspects of the pain reaction, this is not surprising. The degree of overlap is such that one measure (for example the sensory quality of the pain) will be as successful as any other in terms of predictive power. However, it should be noted that by deleting all variables except the one with the best predictive power, larger rates of false negatives and false positives result. The lowest error rate and the highest percent of correct positives occur with the prediction of subchronic status by the inclusion of all the dependent variables at the acute assessment point. As can be seen in Table 5, the predictive power weakens as the time interval increases. Predictions from acute responses to sub-chronic status, and from subchronic responses to chronic status are better than predictions across the full 6 month period. The best results occur when predictions are made on subchronic responses with respect to chronic status. Across this interval 80% of cases are correctly classified, and a very high detection of those who will not become chronic is evident (94.2%). Litigious involvements A sizeable proportion of the sample onset of pain. The longitudinal study ment and the development of chronic of the two rehabilitation approaches individuals to have significantly more
(48%) reported contacting their lawyers by 7 days from the revealed a significant association between litigious involvepain at 6 months (Philips & Grant, 1991). A comparison showed no significant difference on the trend for litigating chronic difficulties.
CONCLUSION It appears from this preliminary study that the type of rehabilitation approach provided early after the onset of an acute back injury may prove far less important than the provision of behavioral counseling. Those individuals who received this early behavioral counseling showed a trend towards an earlier return to normal, and a reduced likelihood of persisting pain difficulties. Although the differences were not statistically significant, the trends were encouraging. Only one session of behavioral counseling was given, which is not likely to have been a sufficient intervention. Future studies would benefit from elaborating the counseling sessions to see if larger efforts are produced. In addition, such a study may show a differential effect of the two rehabilitation approaches. Although there was a significant change in exercise routines by individuals in the two rehabilitation strategies compared (‘let pain guide’ vs graded activation), they had no significant effect on outcome. Letting pain guide return to normal may be an adequate approach as long as it is correctly taught to the individual, who learns how to pace activity against pain levels. Poor results from this approach may have been due to lack of counseling rather than to the strategy itself. The compliance of the Ss with the rehabilitation approaches was checked by evaluation of the reports of their exercise routines. There was significant difference between the two groups; i.e. the Ss following the advice to regulate activity either by pain levels or independent of pain. This change
The prevention of chronic back pain
449
in approach to exercise persisted through to 6 months-a change that seems to have been adequately achieved by the short counseling session. However, an independent measure of compliance was not achieved in this study and needs to be considered in future work. Little time is spent by physicians counseling acute pain sufferers on the steps they would need to take to return to normal. It is presumed that as healing occurs over the first 4-6 weeks pain and disability will decline in a synchronous manner. A longitudinal study (Philips & Grant, 1991) makes it clear that synchronous change is not the norm, and that the recovery from an acute injury is considerably longer than has been suggested (Nachemson, 1984). During this period, appropriate counseling and expectations are likely to make a considerable difference to the recovery process. The present preliminary investigation supports this notion and it is hoped it will encourage future studies to increase the behavioral counseling component in order to assess its role in pain prevention. This study suggests that it is feasible to consider tagging individuals and that it can be done most effectively at the 3 month (subchronic) point. Immediate pain reactions within days of onset provides some early clues as to those who will continue to report pain post healing. The quality of the pain experience, the provoked cognitions, and the appraisals of the pain experience, as well as anxiety and immediate behavioral responses are all predictors of early course. However, at the 3 month point (sub-chronic) remarkably accurate predictions can be made of individuals who are unlikely to have continuing pain difficulties or to become disabled. The therapeutic and financial resources can thus be focused on those who may develop difficulties. Thus, psychological reactions to acute pain will allow the identification of a group most likely to have pain at 3 months, and subsequently at 6 months. At the subchronic point, predictions can be made about the likelihood of complete recovery of any individual case. It is hoped to extend this preliminary work over the next few years in order to evaluate a sufficient sample to allow specific cut-off values to be established. With this normative data clinicians will have the basis for objective ‘tagging’ and implementation of preventive strategies as early as the acute stage. Currently psychological methods of managing pain are sought only after many years of physical interventions and specialist referrals. Little if any attempt is made at present to intervene in the evolution of chronic pain problems by providing educational advice or counseling at earlier stages. The results of this study and of the longitudinal study (Philips & Grant, 1991) suggest that it may be possible to intervene and affect the course as early as 2 weeks after the injury. Future studies attempting to ‘tag’ vulnerable individuals would be wise to extend their dependent measures from those highly correlated to the pain problem (as was done in this study) to others that are now recognized to be important. Such pre-injury factors as work satisfaction, pre-pain adjustment, history of psychiatric problems, would be well included in future logistic regression analyses. They are likely to interact in important ways with psychological reactions in prolonging disability, and possibly influencing the evolution of the chronic pain problems. Incorporating more of these types of measures may allow even more precise predictions to be made of individuals who will be vulnerable to continuing pain. Litigious involvement has been found to be an important factor in the persistence of chronic pain (Philips & Grant, 1991). It also appears that minimal behavioral counseling or rehabilitation of either rehabilitation strategy cannot act to prevent chronicity for individuals engaged in litigation. The influence of the latter is more powerful than the simple intervention undertaken in this study. Were the counseling to be more extensive and over a longer period, it remains possible that the strong trend to develop chronic problems in litigators could be influenced. It is important to keep in mind the limitations of this preliminary investigation. The Ss were drawn from both general practitioners and emergency departments, and there is likely to be some type of sampling bias in this selection. However, this limitation would not appear to have a significant impact on regression analysis or analysis of course. More serious, however, is the difference in the attrition rate between groups. Although the dropout rate may have been higher in Group B because of the recovery having been complete, it is equally possible that graded reactivation made more demands on these Ss and they tended to dropout, despite continuing pain, rather than admit that they had not completed their program. Future studies will need to attempt to reduce the attrition rate and/or to follow-up a representative proportion of the dropout Ss.
H. C.
450
PHILIPS~C al.
If the Ss were tending to dropout because of the demand upon them, a more elaborate counseling and training approach (recommended above) may significantly reduce the attrition rate. In summary, it appears that by the three month point one can predict which individuals will resolve their difficulties and not develop chronic pain difficuities. In addition one can make judgments at the acute stage with an accuracy better than chance of which groups will continue experiencing pain at 3 months and 6 months. These predictions are made on the basis of pain parameters (cognitive, behavioral, objective). It is likely that incorporating important non-pain measures, could result in more accurate predictions. The implication is that the ever increasing resources being funnelled into chronic pain management might be more effectively spent on prevention at a very early stage. As early as a few weeks after the onset of an acute problem, behavioral counseling and advice may prove cost-efficient in limiting the progression of the pain problem and encouraging the reduction of chronic pain disability. ~c~ff~~~e~~e~e~6~-Kirn Eryl, Rhonda Dyer and the referring physicians of University Hospital, Shaughnessy Site. Funding for the research was provided by B.C. Med. Foundation and I.C.B.C. REFERENCES Beck, A. T., Ward, C. H., Mendelson, M., Mock, J. & Erbaugh, J. (1961). An inventory for measuring depression. Archiues of General Psychiatry 4, 561-571.
Bergner, M., Bobbitt, R. A., Carter, W. B. & Gibson, B. S. (1981). Sickness Impact Profile: Development and final revision of a health status measure. +?leriical Care, f9, 787-805. Bonica, J. J. (1980). Pain research & therapy: Past and current status & future needs. In En, L. K. Y. & Bonica, J. J. (Eds), Pain, discomfort and humanitarian care (pp. 1-46). Amsterdam: Elsevier. Deyo, R. A., Diehl, A. K. & Rosenthal, M. (1986). How many days of bedrest for acute low back pain? New England Journal of Medicine, 313, 17, 1064-1070.
Dillon, W. R. & Goldstein, M. (1984). Multivariate analysis: Methods & applications. New York: Wiley. Erickson, R. F. (1989). The conservative medical management of pain. In Camic, P. & Brown, F. D. (Eds), Assessing chronic pain (pp. 47-70). New York: Springer. Fordyce, W. E., Brockway, J., Bergman, J. A. & Spengfer, D. (1986). Acute back pain: A control group comparison of behavioural vs traditional management methods. Journal of Behavioral Medicine, 9, 127-140. Gilbert, J. R., Taylor, D. W., Hildebrand, A. & Evans, C. (1985). Clinical trial of common treatment for back pain. British Medical Journal 291, 79 1.
Holzman, A. D. & Turk, D. C. (Eds) (1986). Pain management: A handbook of psychological treatment approaches. Oxford: Pergamon General Psychology Series. Hunter. M. 11983X The headache scale: A new annroach to the assessment of headache pain based on pain descriptions. 1_ Pain, 16,‘36l_j73.
Nachemson, A. (1982). The natural course of low back pain. in White, A. A. & Gordon, S. L. (Eds), Sytmposium on idiopathic low back pain (pp. 4651). St Louis, MO.: Mosby. Nachemson, A. L. (1984). The prevention of chronic back pain: The orthopedic challenge of the ‘80’s. Buifetin of the Hospitals for Joint Diseases, 44, l-10.
Philips, Philips, Philips, Philips,
H. H. H. H.
C. (1987). The effects of behavioural treatment on chronic pain. Behauiour Research and Therapy 25, 3655377. C. (1988). The psychological manugement of chronic pain. New York: Springer. C. (1989). Thoughts provoked by pain. Bebaviour Research and Therapy, 27, 469473. C. & Grant, L. (1991) The evolution of chronic back pain problems: A longitudinal study. Behaz!iour Research
and Therapy, 29, 435441.
Philips, H. C. & Jahanshahi, M. (1986). The components of pain behaviour report, Behaviour Research and Therapy, 24, 117-125.
Report of The Quebec Task Force on Spinal Disorders (1987). Scientific approach to the assessment and management of activity-related spinal disorders: A monograph for clinicians. Spine, suppl. I, 12, 59-559. Speilberger, C. S. (1983). Manual for the State-Traif Anxiety Inventory. Palo Alto, Calif. Consulting Psychologist Press. The Classification of Chronic Pain (1986). Pain, suppl. 3. Turk, D. C., Meichenbaum, D. & Genest, M. (1983). Pain & behavjoural medicine-a cognitive-behavioural perspective. Guilford Press, New York.
Res.
Thu.
Vol.
29, No.
5, pp.
443450,
0005-7967/91
1991
$3.00
+ 0.00
Copyright 0 1991Pergamon Press plc
Printed in Great Britain. All rights reserved
THE PREVENTION OF CHRONIC PAIN AND DISABILITY: A PRELIMINARY INVESTIGATION H . C . PHILIPS,~* L. GRANT’ and J. BERKOWITZ* ‘Psychology Department, University Hospital, Shaughnessy Site, Vancouver, British Columbia, Canada V6H 3Nl and ZBerkowitz & Associates, 4160 Staulo Crescent, Vancouver, British Columbia, Canada V6N 3S2 (Received 10 December
1990; received for publication 15 April 1991)
Summary-A preliminary investigation was undertaken on 117 acute back pain cases, to assess the utility of counseling at the acute stage upon the course of recovery over the subsequent 6 months. In addition, the extent to which psychological reactions to acute injury would allow the ‘tagging’ of individuals at risk for chronic pain problems, was studied. The minimal rehabilitation counseling proved inadequate to effect the course of recovery, but remarkably accurate predictions were possible at the sub-chronic point (3 months) as to who would make complete recoveries.
INTRODUCTION
With the development of multidisciplinary clinics, psychologists have been involved in developing new techniques for the management of chronic pain problems (Turk, Meichenbaum & Genest, 1983; Holtzman & Turk, 1986; Philips, 1988). Cognitive and behavioral methods have focused on reduction of pain and disability, and the teaching of management techniques that can make sufferers increasingly independent of medical services. Although the results are very encouraging, most clinics have long waiting lists and there appears to be an escalating incidence of chronic pain problems (Nachemson, 1984). Health care costs are rising, and it has been estimated that in the United States alone, over 60 billion dollars are spent per year on chronic pain problems (Bonica, 1980). With the increasing cost and size of this problem, it is clear that resources need to be focused on those people liable to develop chronic pain problems, with the aim of prevention or reduction of the size of the problem (Nachemson, 1984). If individuals could be ‘tagged’ during the acute period (within days of onset of an acute episode) resources could be directed toward these individuals. As preventive techniques evolve, total health care costs will shrink. A longitudinal study carried out by the authors (Philips & Grant, 1991) suggests that current estimates of those who are likely to develop chronic pain (lO-15% of acute back injuries, Nachemson, 1982) may be underestimates. Up to 40% of the sample studied continued reporting pain 6 months after acute episode. This suggests that there are a large number of people who continue having pain post-healing, and on whom preventive work could be focused. Currently, little attention is given to prevention. Spontaneous remission is assumed to parallel healing and no counseling is considered until pain has persisted for years. Physical treatments continue to be explored even when healing is complete. By the time pain sufferers are referred to a pain management clinic, they may have seen multiple specialists and endured pain for nearly a decade (Philips, 1987). Over the last few years there has been a trend to consider the end of the ‘acute period’ as coinciding with completion of tissue healing. The Classification of Chronic Pain (IAP: 1986) has suggested that the term ‘chronic’ be used at 3 months after the acute episode, while the Report of the Quebec Task Force (1987) on back pain has shifted it even closer to initial injury. They suggest a cut-off at 7 weeks, identifying a ‘sub-acute period’ between 7 days and 7 weeks post-onset. Some empirical support for this shift can be found in Philips and Grant, 1991. Therefore, preventive interventions would need to be undertaken in the early weeks following an acute back injury. *Author for correspondence. 443
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Although not formulated as preventive methods, different rehabilitation approaches have been used. The traditional approach was to counsel withdrawal and avoidance of activity and encourage bedrest. This passive approach to the recovery period has been superseded by a more active one which has been described as ‘letting pain guide’. This approach encourages the patient to regulate their active reinvolvement in daily life by assessing pain levels. If pain increases, rest and withdrawal is encouraged. When pain subsides, a return to normal activity is recommended. In contrast, some physicians are now recommending graded exposure and return to activity, irrespective of pain-to begin within 72 hr of the onset of an acute pain episode. They are counseling a graduated exercise program which begins at a low level and continues daily, despite changes in pain level. Results to date have not compared these three strategies in any systematic manner. However, there is sufficient evidence of the detrimental effects of total avoidance and bedrest over long periods to have made this first rehabilitation strategy unacceptable {Deyo, Diehl & Rosenthal, 1986; Gilbert, Taylor, Hildebrand & Evans, 1985). The other two approaches need to be compared; preliminary results suggest that graded exposure may be an important way of limiting the development of chronic problems (Fordyce, Brockway, Bergman & Spengler, 1986). As yet no attempt has been made to consider to what extent counselling at the acute stage has an effect, irrespective of the type of advice given. In order to explain any rehabilitation rationale, the doctor or therapist provides an explanatory framework which may act to reduce the emotional reaction and limit avoidance behavior. The aim of the current study was to evaluate the preventive power of the two common rehabilitation approaches to acute back pain: ‘letting pain guide’ the return to normal, and graded reactivation, irrespective of pain. This study also systematically assesses the utility of early behavioral counseling in how to apply these two phiIosophies of rehabilitation, not only to exercise, but to other aspects of the person’s life. Finally, a preliminary attempt is made to ‘tag’ individuals at risk for developing chronic pain, on the basis of their reaction to acute injury. Early identification of prone individuals would allow preventive techniques to be focused on them. METHODOLOCY Subjects
117 individuals were referred to the study from Emergency Departments and general practitioners. They had reported their first onset of acute back or neck pain within 15 days of its onset and had no signs of neural or discal damage. They were each paid $75 at the completion of the last of their three sessions over a 6 month period. The payments were used as incentives to keep individuaIs involved in the study, irrespective of whether or not pain was still present. The average age was 32 yr (F7.6 yr); 42.7% were male, 57.3% were female. The initial visit occurred, on average, 7.9 days (f4.6 days) after pain onset. The second visit (subchronic) was planned for 3 months post-onset and occurred, on average, 13.7 weeks (+ 1.2 weeks) post-onset. The third visit (‘chronic’) occurred at 6 months post-onset. The attrition rate at 6 months was 21%. (This was due to Ss moving away, being unwilling to attend, being advised against it by their lawyers, or not being able to be contacted by the researchers.) This left 91 cases at 3 months, and 92 cases at 6 months. (One individual unable to attend at 3 months, was available at the 6 month point). Procedure
All Ss were contacted by phone and a visit was arranged for them in the research offices. The acute assessment lasted 45 min, entailing a structured interview (obtainable from the authors), the completion of questionnaire and the provision of rehabilitation advice. Follow-up contacts at 3 months (subchronic) and 6 months required only a 30-min structured interview (also available from the authors).
The battery of questionnaires completed at each of the three contact points consisted of: Beck Depression Inventory (Beck, Ward, Mendelson, Mock & Erbaugh, 1961), State-Trait Anxiety Inventory (Speilberger, 1983), Pain Behaviour Checklist (Philips & Jahanshahi, 1986), Pain
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Evaluation Questionnarie (Philips, 1989) Sickness Impact Profile (Bergner, Bobbit, Carter & Gilson, 1981), and Pain Quality Questionnaire (Hunter, 1983). In addition, a structured interview was designed to collect information on continuation of pain, pain intensity and contingencies for exercising (i.e. pain dependent exercise or exercise irrespective of pain). Examples of the interview may be obtained from the authors. Design Ss were randomly allocated to one of two groups, defined by the rehabilitation methods used. Group A. ‘Let pain guide’ the return to normal. The aim was to return to the previous level of
functioning if pain reductions allowed. Group B. Graded and gradual reactivation approach, building back to normal functioning. Pain was not a guide to the rate of reactivation. An incremental schedule of activity was recommended. The two different rehabilitation approaches were explained and demonstrated to Ss with a set of physical exercises, appropriate to the individuals on the basis of their pain locus (upper back and neck vs middle and lower back) and fitness level. Ss allocated to Group A (let pain guide) were asked to let pain levels guide them as to which excercises to undertake and how many of each to do. Those in Group B (graded reactivation) were told to use a gradual incremental basis provided for each exercise irrespective of current pain levels. (Instructions and exercise routines obtainable from the authors.) The two groups were further divided to compare two counseling methods. Behavioral counseling provided explanations of how the rehabilitation approach was to be applied to their particular lives. It was undertaken with respect to exercise, social activities and return to work. Problem-solving was done with the individuals in order to help them see how the approach could be used over all the different areas of their life. Psychotherapy counseling (Control counseling) provided general non-directive discussion with respect to the significance of the pain episode to them and their history of previous pain experiences. No behavioral instruction was given in the control counseling. Although this allocation led to four groups (Rehabilitation Group A: Behavioral and Control counseling; Rehabilitation Group B: Behavioral and Control counseling) insufficient numbers of Ss in this preliminary study prevented a four-way group comparison. Group comparisons were made, however, between three groups, Group A: Behavioral counseling (n = 34) Group B: Behavioral counseling (n = 35) and Group B: Control counseling (n = 40). RESULTS Prevention
of chronic pain
Approximately 40% of the individuals, followed over the 6 month period, reported that they still experienced pain which they considered had started at the acute episode. Using the presence or absence of reported pain at the 6 month point as the criterion of chronic pain, no significant difference was evident between the two rehabilitation approaches. In other words, there was no suggestion that the two different policies (Let pain guide vs graded activation) had differential effects on the chronic pain process. However, a trend was evident when the groups were compared with respect to the presence or absence of behavioral advice as to how to apply the rehabilitation advice to their own lives (see Table 1). Those receiving the behavioral counseling had a higher proportion of cases with no pain, than cases with pain. This was not true for those having an equal amount of discussion with the counselor but without any behavioral instruction. Although the two approaches (Groups A and B) did not significantly influence pain courseper se, they appeared to have successfully changed exercise patterns. 86% of Group B Ss began exercising Table I. Numbers of Ss reporting chronic pain or pain-free status at 6 months in the counseling and control groups
Pain No pain Total
Control
Behavioral counseling
Total
16 17 33
23 36 59
39 53 92
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Table
et al.
2. Percentage of cases within each group who reported exercise patterns dependent presence/level, or independent of pain, at 3 and 6 month assessment points Sub-chronic Pain dependent exercise (%)
Group A (let pain guide recovery) Group B Ceraded activation)
(3 months)
Chronic
on pain
(6 months)
Exercise irrespective of pain (%)
Pain dependent exercise (%)
Exercise irrespective of pain (%)
75.9
20.0
66.0
26.0
21.4
59.0
34.0
63.0
within 3 days of their visit to the study offices. In contrast, only 55% of Group A began at this early stage. The two groups reported no difference with respect to the regularity of their exercise regime at the 3 month point, with 4&50% exercising a few times a week or more frequently. However, there was a significant difference between the groups with respect to when they exercised (x2 = 28.2, P < 0.005); this was consistent with the respective rehabilitation advice (see Table 2). Significantly more individuals in Group A (let pain guide) reported exercise depended on pain levels. The differences were still present at 6 months post-onset, suggesting a prolonged change in behavior as a result of minimal counseling with respect to the approach to be taken to exercise. However, the behavioral changes did not prevent chronic pain developing. The two rehabilitation approaches did not have any significant impact on the strong association of litigious involvement and the development of chronic pain (Philips & Grant, 1991). There is no evidence that this association was weakened either by the rehabilitation approach or by the presence or absence of psychological counseling. Unfortunately, the attrition rate differed between the groups. Where active involvement was requested (Group B), and especially where no behavioral counseling was provided to support the rehabilitation method, the drop-out rate was highest (see Table 3). Tugging
individuals at risk ,for the development
of chronic pain problems
Because of the lack of significant effect of group allocation on pain state at outcome, it was possible to combine all the individuals into one group in order to investigate the relationship of acute reaction to pain and subsequent course. Cross-sectional analyses of the data at the three time points (acute, subchronic and chronic) showed remarkably similar results at the 3 and 6 month points (cf. Philips & Grant, 1991). Consequently, the most important prediction appears to be between acute onset and subchronic status. The first 3 month period led to the following findings. (1) When the locus of acute pain was in the upper back (upper spine and/or neck), it was more likely that the pain would still be present at three months (x2 = 8.7, P < 0.02). Acute pain provoked by injury, rather than by sports accidents, overuse or spontaneous onset, was more likely to be present at the 3 month point (x2 = 24.9, P < 0.000). Individuals reporting legal involvement at the acute onset were more likely to report pain persisting at the 3 month point (x2 = 13.2, P < 0.001). Thus legal involvement, upper spine and neck pain, and ‘injury’ etiologies appear to be relevant acute characteristics with respect to pain persistence. (2) Examining the acute pain response in more detail, the sample was divided at the acute assessment into two groups defined by pain status at the subchronic stage. A simple division by Table 3. Number
of cases per group and attrition months ChOUDS
Group
Group
A:
B:
No. of cases
rate (%) at 6 Drop-outs (%)
Let pain guide counseled control
34 8
9 0
Graded activation counseled control
35 40
23 38
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The prevention of chronic back pain Table 4. Difference between mean scores on dependent measures at the acute assessment, for two groups defined on the basis of pain status at 3 months (subchronic evaluation) Acute assessment Pain intensity (rating O-100)
Pain
Pain status at 3 months I No pain
P
43.0(8.90)
2.33
0.020
I .21 (0.57) 1.62 (0.64)
0.76 (0.46) 1.16(0.59)
4.12 3.51
0.001 0.005
Pain behavior avoidance complaint
52% (21 .O) 67% (22.0)
43% (21.0) 65% (23.0)
I .94 0.49
0.056 NS
Pain evaluation questionnaire
54.5 (23.99)
41.5 (20.51)
2.76
0.007
Pain quality sensory affective
Beck depression Inventory STAI: State Sickness Impact _ _. Profile Total score
52.1 (17.65)
10.9 (8.27) 47.74(13.35)
14.8 (10.80)
8.22 (7.14)
1.61
NS
39.62 (I 1.71)
3.05
0.003
9.3 (8.08)
2.8
0.007
presence or absence of continuing pain at 3 months was used as the criterion. Table 4 provides the mean and standard deviation of each of the dependent measures for these two groups at the acute assessment. Those at risk for continuing pain at 3 months were significantly different at the acute stage from those who recovered within a 3 month period. They reported significantly higher acute pain levels, both with respect to sensory and affective qualities. They also reported significantly more negative cognitive reactions to pain, higher anxiety, and detailed a much larger behavioral impact of the pain on their everyday lives (Sickness Impact). They were not differentiated with respect to depression, which was found to be within normal limits. A trend toward higher levels of avoidance behavior was present for those who subsequently reported pain at 3 months. Highly significant differences were found between groups at three months (defined by pain status at 6 months) on all measures, exception the Beck Depression Inventory. In contrast, tagging individuals at the acute stage with respect to their 6 month status is not as successful. Pain rated intensity and the sensory and affective component of the pain experience are significantly different, but the other variables are no longer useful predictors across this longer period of time. (3) The above analyses compared the characteristics of those who subsequently reported continuing pain with those who did not, by undertaking t-tests on the dependent variables at the acute stage. As a consequence, the group more at risk could be defined at onset by pain qualities and psychological reactions to acute injury. A more powerful method, Stepwise Logistic Regression, was also used, to evaluate the relative potency of the predictive variables. Logistic regression has weaker distributional assumptions than discriminant analysis, but is a comparable technique (Dillon & Goldstein, 1984). Logistic regression provides a classification table which gives the percentage of correctly classified cases, as well as specificity (percent correct negative), sensitivity (percent correct positive), false negatives, and false positives. Three predictions were obtained: subchronic from acute, chronic from subchronic, and chronic from acute. The effectiveness of each prediction was measured by comparison with predictions based solely on the frequency of response on the dependent variables. For example, at 6 months 57.1% of cases would be correctly classified by predicting all Ss to be pain-free. (A prediction of ‘not pain-free’ for all cases would be correct in 42.9% of the cases.) Many of the predictions are in fact markedly better than chance. There are significant and considerable improvements in predictive power especially with respect to predictions of chronic status from the three month point. (See Table 5). The best predictions of chronic status can be made at 3 months, when 80.0% can be correctly classified. Here, specificity is highest and false negatives lowest. Therefore at 3 months, correct predictions of those who will not have chronic pain can be made with remarkable accuracy (94.2% correct). Prediction of those who will have chronic problems, although better than chance, is not as accurate (60.5%). The relative predictive power of each of the dependent measures was evaluated using a backward logistic regression analysis. The sensory pain component at the acute stage could correctly classify
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et al.
Table 5. Predictions of pain status (in % correctly classified) from acute and subchronic stepwise logististic regression analysis on all of the dependent measures
% Correctly classified (using all dependent measures) (A) Specificity (correct negatives) (B) Sensitivity (correct positives) (C) False negatives (D) False oositives
responses
using
Prediction of subchronic status from acute responses
Prediction of chronic status from acute responses
Prediction of chronic status from subchronic responses
75.5
68.1
80.0
84.0
80.8
94.2
63.0
51.3
60.5
21.6 22.2
33.0 31.0
11.5 23.4
67.0% of cases with respect to their subchronic status. The other dependent measures only improve the accuracy of the prediction to 74.5%. This was due to the high intercorrelation between the measures taken at the acute point. As they are all measures of aspects of the pain reaction, this is not surprising. The degree of overlap is such that one measure (for example the sensory quality of the pain) will be as successful as any other in terms of predictive power. However, it should be noted that by deleting all variables except the one with the best predictive power, larger rates of false negatives and false positives result. The lowest error rate and the highest percent of correct positives occur with the prediction of subchronic status by the inclusion of all the dependent variables at the acute assessment point. As can be seen in Table 5, the predictive power weakens as the time interval increases. Predictions from acute responses to sub-chronic status, and from subchronic responses to chronic status are better than predictions across the full 6 month period. The best results occur when predictions are made on subchronic responses with respect to chronic status. Across this interval 80% of cases are correctly classified, and a very high detection of those who will not become chronic is evident (94.2%). Litigious involvements A sizeable proportion of the sample onset of pain. The longitudinal study ment and the development of chronic of the two rehabilitation approaches individuals to have significantly more
(48%) reported contacting their lawyers by 7 days from the revealed a significant association between litigious involvepain at 6 months (Philips & Grant, 1991). A comparison showed no significant difference on the trend for litigating chronic difficulties.
CONCLUSION It appears from this preliminary study that the type of rehabilitation approach provided early after the onset of an acute back injury may prove far less important than the provision of behavioral counseling. Those individuals who received this early behavioral counseling showed a trend towards an earlier return to normal, and a reduced likelihood of persisting pain difficulties. Although the differences were not statistically significant, the trends were encouraging. Only one session of behavioral counseling was given, which is not likely to have been a sufficient intervention. Future studies would benefit from elaborating the counseling sessions to see if larger efforts are produced. In addition, such a study may show a differential effect of the two rehabilitation approaches. Although there was a significant change in exercise routines by individuals in the two rehabilitation strategies compared (‘let pain guide’ vs graded activation), they had no significant effect on outcome. Letting pain guide return to normal may be an adequate approach as long as it is correctly taught to the individual, who learns how to pace activity against pain levels. Poor results from this approach may have been due to lack of counseling rather than to the strategy itself. The compliance of the Ss with the rehabilitation approaches was checked by evaluation of the reports of their exercise routines. There was significant difference between the two groups; i.e. the Ss following the advice to regulate activity either by pain levels or independent of pain. This change
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in approach to exercise persisted through to 6 months-a change that seems to have been adequately achieved by the short counseling session. However, an independent measure of compliance was not achieved in this study and needs to be considered in future work. Little time is spent by physicians counseling acute pain sufferers on the steps they would need to take to return to normal. It is presumed that as healing occurs over the first 4-6 weeks pain and disability will decline in a synchronous manner. A longitudinal study (Philips & Grant, 1991) makes it clear that synchronous change is not the norm, and that the recovery from an acute injury is considerably longer than has been suggested (Nachemson, 1984). During this period, appropriate counseling and expectations are likely to make a considerable difference to the recovery process. The present preliminary investigation supports this notion and it is hoped it will encourage future studies to increase the behavioral counseling component in order to assess its role in pain prevention. This study suggests that it is feasible to consider tagging individuals and that it can be done most effectively at the 3 month (subchronic) point. Immediate pain reactions within days of onset provides some early clues as to those who will continue to report pain post healing. The quality of the pain experience, the provoked cognitions, and the appraisals of the pain experience, as well as anxiety and immediate behavioral responses are all predictors of early course. However, at the 3 month point (sub-chronic) remarkably accurate predictions can be made of individuals who are unlikely to have continuing pain difficulties or to become disabled. The therapeutic and financial resources can thus be focused on those who may develop difficulties. Thus, psychological reactions to acute pain will allow the identification of a group most likely to have pain at 3 months, and subsequently at 6 months. At the subchronic point, predictions can be made about the likelihood of complete recovery of any individual case. It is hoped to extend this preliminary work over the next few years in order to evaluate a sufficient sample to allow specific cut-off values to be established. With this normative data clinicians will have the basis for objective ‘tagging’ and implementation of preventive strategies as early as the acute stage. Currently psychological methods of managing pain are sought only after many years of physical interventions and specialist referrals. Little if any attempt is made at present to intervene in the evolution of chronic pain problems by providing educational advice or counseling at earlier stages. The results of this study and of the longitudinal study (Philips & Grant, 1991) suggest that it may be possible to intervene and affect the course as early as 2 weeks after the injury. Future studies attempting to ‘tag’ vulnerable individuals would be wise to extend their dependent measures from those highly correlated to the pain problem (as was done in this study) to others that are now recognized to be important. Such pre-injury factors as work satisfaction, pre-pain adjustment, history of psychiatric problems, would be well included in future logistic regression analyses. They are likely to interact in important ways with psychological reactions in prolonging disability, and possibly influencing the evolution of the chronic pain problems. Incorporating more of these types of measures may allow even more precise predictions to be made of individuals who will be vulnerable to continuing pain. Litigious involvement has been found to be an important factor in the persistence of chronic pain (Philips & Grant, 1991). It also appears that minimal behavioral counseling or rehabilitation of either rehabilitation strategy cannot act to prevent chronicity for individuals engaged in litigation. The influence of the latter is more powerful than the simple intervention undertaken in this study. Were the counseling to be more extensive and over a longer period, it remains possible that the strong trend to develop chronic problems in litigators could be influenced. It is important to keep in mind the limitations of this preliminary investigation. The Ss were drawn from both general practitioners and emergency departments, and there is likely to be some type of sampling bias in this selection. However, this limitation would not appear to have a significant impact on regression analysis or analysis of course. More serious, however, is the difference in the attrition rate between groups. Although the dropout rate may have been higher in Group B because of the recovery having been complete, it is equally possible that graded reactivation made more demands on these Ss and they tended to dropout, despite continuing pain, rather than admit that they had not completed their program. Future studies will need to attempt to reduce the attrition rate and/or to follow-up a representative proportion of the dropout Ss.
H. C.
450
PHILIPS~C al.
If the Ss were tending to dropout because of the demand upon them, a more elaborate counseling and training approach (recommended above) may significantly reduce the attrition rate. In summary, it appears that by the three month point one can predict which individuals will resolve their difficulties and not develop chronic pain difficuities. In addition one can make judgments at the acute stage with an accuracy better than chance of which groups will continue experiencing pain at 3 months and 6 months. These predictions are made on the basis of pain parameters (cognitive, behavioral, objective). It is likely that incorporating important non-pain measures, could result in more accurate predictions. The implication is that the ever increasing resources being funnelled into chronic pain management might be more effectively spent on prevention at a very early stage. As early as a few weeks after the onset of an acute problem, behavioral counseling and advice may prove cost-efficient in limiting the progression of the pain problem and encouraging the reduction of chronic pain disability. ~c~ff~~~e~~e~e~6~-Kirn Eryl, Rhonda Dyer and the referring physicians of University Hospital, Shaughnessy Site. Funding for the research was provided by B.C. Med. Foundation and I.C.B.C. REFERENCES Beck, A. T., Ward, C. H., Mendelson, M., Mock, J. & Erbaugh, J. (1961). An inventory for measuring depression. Archiues of General Psychiatry 4, 561-571.
Bergner, M., Bobbitt, R. A., Carter, W. B. & Gibson, B. S. (1981). Sickness Impact Profile: Development and final revision of a health status measure. +?leriical Care, f9, 787-805. Bonica, J. J. (1980). Pain research & therapy: Past and current status & future needs. In En, L. K. Y. & Bonica, J. J. (Eds), Pain, discomfort and humanitarian care (pp. 1-46). Amsterdam: Elsevier. Deyo, R. A., Diehl, A. K. & Rosenthal, M. (1986). How many days of bedrest for acute low back pain? New England Journal of Medicine, 313, 17, 1064-1070.
Dillon, W. R. & Goldstein, M. (1984). Multivariate analysis: Methods & applications. New York: Wiley. Erickson, R. F. (1989). The conservative medical management of pain. In Camic, P. & Brown, F. D. (Eds), Assessing chronic pain (pp. 47-70). New York: Springer. Fordyce, W. E., Brockway, J., Bergman, J. A. & Spengfer, D. (1986). Acute back pain: A control group comparison of behavioural vs traditional management methods. Journal of Behavioral Medicine, 9, 127-140. Gilbert, J. R., Taylor, D. W., Hildebrand, A. & Evans, C. (1985). Clinical trial of common treatment for back pain. British Medical Journal 291, 79 1.
Holzman, A. D. & Turk, D. C. (Eds) (1986). Pain management: A handbook of psychological treatment approaches. Oxford: Pergamon General Psychology Series. Hunter. M. 11983X The headache scale: A new annroach to the assessment of headache pain based on pain descriptions. 1_ Pain, 16,‘36l_j73.
Nachemson, A. (1982). The natural course of low back pain. in White, A. A. & Gordon, S. L. (Eds), Sytmposium on idiopathic low back pain (pp. 4651). St Louis, MO.: Mosby. Nachemson, A. L. (1984). The prevention of chronic back pain: The orthopedic challenge of the ‘80’s. Buifetin of the Hospitals for Joint Diseases, 44, l-10.
Philips, Philips, Philips, Philips,
H. H. H. H.
C. (1987). The effects of behavioural treatment on chronic pain. Behauiour Research and Therapy 25, 3655377. C. (1988). The psychological manugement of chronic pain. New York: Springer. C. (1989). Thoughts provoked by pain. Bebaviour Research and Therapy, 27, 469473. C. & Grant, L. (1991) The evolution of chronic back pain problems: A longitudinal study. Behaz!iour Research
and Therapy, 29, 435441.
Philips, H. C. & Jahanshahi, M. (1986). The components of pain behaviour report, Behaviour Research and Therapy, 24, 117-125.
Report of The Quebec Task Force on Spinal Disorders (1987). Scientific approach to the assessment and management of activity-related spinal disorders: A monograph for clinicians. Spine, suppl. I, 12, 59-559. Speilberger, C. S. (1983). Manual for the State-Traif Anxiety Inventory. Palo Alto, Calif. Consulting Psychologist Press. The Classification of Chronic Pain (1986). Pain, suppl. 3. Turk, D. C., Meichenbaum, D. & Genest, M. (1983). Pain & behavjoural medicine-a cognitive-behavioural perspective. Guilford Press, New York.
