R. B. Cutler

Chronic pain-associated depression: Antecedent or consequence of chronic pain? A review

OBJECTIVE To determine the current status for the association of chronic pain and depression and to review the evidence for whether depression is an antecedent or consequence of chronic pain (CP). DESIGN A computer and manual literature review yielded 191 studies that related to the pain-depression association. These reports were reviewed and sorted into seven categories relating to the topic of this paper. Eighty-three studies were then selected according to inclusion criteria and subjected to a structured review. SETTING Any medical treatment setting including pain treatment as inclusion criteria for selection of studies. PATIENTS Any patients with any type of chronic pain. RESULTS The reviewed studies were consistent in indicating that there is a statistical relationship between chronic pain and depression. For the relationship between pain and depression, there was greater support for the consequence and scar hypotheses than the antecedent hypothesis. CONCLUSIONS Depression is more common in chronic pain patients (CPPs) than in healthy controls as a consequence of the presence of CP. At pain onset, predisposition to depression (the scar hypothesis) may increase the likelihood for the development of depression in some CPPS. Because of difficulties in measuring depression in the presence of CP, the reviewed studies should be interpreted with caution.

Does Nonsurgical Pain Center Treatment of Chronic Pain Return Patients to Work?: A Review and Meta-analysis of the Literature

Evidence in the literature relating to return to work as an outcome variable for nonsurgical treatment for chronic pain was examined. Study selection criteria were as follows: a detailed definition of patient work status, delineation of work status pre-treatment and at follow-up, and documentation of the proportion of patients employed at follow-up. Of 171 studies reviewed, 37 fulfilled these selection criteria. Because the data were objective in nature, they were abstracted by the senior author only. For the coded variables of time to follow-up, proportion of patients working pre-treatment and at follow-up and number of patients, descriptive statistics and correlations were calculated. Change in employment status at follow-up was significant (P < .005) for all groups examined. In addition, comparisons for work outcome between treated patients versus patients rejected due to lack of insurance, and between treated patients versus patients who dropped out of treatment were both significant (P < .001). The mean difference in employment at follow-up for treated patients versus those not treated was approximately 50%. The proportion of patients working increased from 20% to 54% post chronic pain nonsurgical treatment. Correlation analyses did not find a significant trend in percent employed with time to follow-up. These results indicate that (1) chronic pain nonsurgical treatment does return patients to work; (2) increased rates of return to work are due to treatment, and (3) benefits of treatment are not temporary.

Chronic pain disability exaggeration/malingering and submaximal effort research

OBJECTIVE This is the first review of chronic pain (CP) malingering/disease simulation research. The purpose of this review was to determine the prevalence of malingering within CP patients (CPPs), whether evidence exists that malingering can be detected within CPPs, and to suggest some avenues of research for this topic. DESIGN A computer and manual literature search produced 328 references related to malingering, disease simulation, dissimulation, symptom magnification syndrome, and submaximal effort. Of these, 68 related to one of these topics and to pain. The references were reviewed in detail, sorted into 12 topic areas, and placed into tabular form. These 12 topic areas addressed the following: existence of malingering within the CP setting; dissimulation, identification simulated (faked) facial expressions of pain; identification of malingering by questionnaire; identification of malingered sensory impairment; identification of malingered loss of hand grip strength; identification of submaximal effort by isometric strength testing; identification of submaximal or malingered effort by isokinetic strength testing; identification of submaximal or malingered effort by the method of coefficient of variation; self-deception; symptom magnification syndrome; and miscellaneous malingering identification studies. Each report, in each topic area, was rated for scientific quality according to guidelines developed by the Agency for Health Care, Policy and Research (AHCPR) for rating the level of evidence presented in the reviewed study. The AHCPR guidelines were then used to rate the strength and consistency of the research evidence in each topic area based on the type of evidence the reports represented. All review conclusions were based on the results of these ratings. SETTING Any medical setting reporting on either malingering or disease simulation, or dissimulation, or submaximal effort and pain. PATIENTS Normal volunteers, CPPs, or any group asked to produce a submaximal or malingered effort or a malingered test profile. RESULTS The reviewed studies indicated that malingering and dissimulation do occur within the CP setting. Malingering may be present in 1.25-10.4% of CPPs. However, because of poor study quality, these prevalence percentages are not reliable. The study evidence also indicated that malingering cannot be reliably identified by facial expression testing, questionnaire, sensory testing, or clinical examination. There was no acceptable scientific information on symptom magnification syndrome. Hand grip testing using the Jamar dynamometer and other types of isometric strength testing did not reliably discriminate between a submaximal/malingering effort and a maximal/best effort. However, isokinetic strength testing appeared to have potential for discriminating between maximal and submaximal effort and between best and malingered efforts. Repetitive testing with the coefficient of variation was not a reliable method for discriminating a real/best effort from a malingered effort. CONCLUSIONS Current data on the prevalence of malingering within CPPs is not consistent, and no conclusions can be drawn from these data. As yet, there is no reliable method for detecting malingering within CPPs, although isokinetic testing shows promise. Claims by professionals that such a determination can be made should be viewed with caution.

The prediction of return to the workplace after Multidisciplinary Pain Center treatment.

The prediction of return to the workplace after Multidisciplinary Pain Center (MPC) treatment has become a major research area. To delineate the variables that predict this outcome, the authors reviewed 164 multidisciplinary outcome studies. Of these, 79 addressed work as an outcome variable. Twenty-six studies attempted to identify patient variables predicting return to the workplace. These latter studies were critically inspected for eight methodological criteria: pain location, follow-up time interval, response percentage and follow-up method, return to work subcategorization, vocational movement, univariate vs. multivariate statistics, multicolinearity and variance, and statistical treatment of dropouts. In addition, other disability studies besides those in the chronic pain area were reviewed for return to the workplace predictor variables. Of these 26 studies, only a few appeared to satisfy the criteria examined. In addition, many studies were in conflict with one another on whether a variable was predictive. The review of the nonchronic pain/disability prediction literature yielded a large number of potential predictors that related to the work area. It is unclear which variables or set of variables predict return to the workplace after MPC treatment. Chronic pain studies may be neglecting the work area as an important source of return to the workplace predictor variables.

Do antidepressants have an analgesic effect in psychogenic pain and somatoform pain disorder? A meta-analysis.

Objective A significant amount of evidence indicates that some antidepressants have an analgesic effect. We wished to determine whether this analgesic effect could be demonstrated in studies that had used antidepressants for the treatment of pain in patients diagnosed with psychogenic pain or somatoform pain disorder. Meta-analysis was used for this purpose. Methods All randomized, placebo-controlled antidepressant treatment studies of patients diagnosed with psychogenic pain disorder or somatoform pain disorder were isolated. These studies were reviewed and relevant statistics were coded. For each study, a single p value for the drug/placebo comparison was found or calculated for pain change scores from pretreatment to completion of treatment. The z scores and effect sizes were calculated for each study, followed by a calculation of an overall z score and effect size. Results Eleven studies fulfilled the inclusion and exclusion criteria for this meta-analysis. The combined difference showed that antidepressants decreased pain intensity in patients with psychogenic pain or somatoform pain disorder significantly more than placebo (z = 5.71, p < .0001). The overall effect size was large (mean = 0.48) and ranged from 0 to 0.91. Conclusions The results indicate that, in patients diagnosed with psychogenic pain or somatoform pain disorder, antidepressant treatment resulted in a reduction in pain that was significantly greater than that of placebo. Possible explanations for these results are discussed.

Are alcoholism treatments effective? The Project MATCH data

BackgroundProject MATCH was the largest and most expensive alcoholism treatment trial ever conducted. The results were disappointing. There were essentially no patient-treatment matches, and three very different treatments produced nearly identical outcomes. These results were interpreted post hoc as evidence that all three treatments were quite effective. We re-analyzed the data in order to estimate effectiveness in relation to quantity of treatment.MethodsThis was a secondary analysis of data from a multisite clinical trial of alcohol dependent volunteers (N = 1726) who received outpatient psychosocial therapy. Analyses were confined to the primary outcome variables, percent days abstinent (PDA) and drinks per drinking day (DDD). Overall tests between treatment outcome and treatment quantity were conducted. Next, three specific groups were highlighted. One group consisted of those who dropped out immediately; the second were those who dropped out after receiving only one therapy session, and the third were those who attended 12 therapy sessions.ResultsOverall, a median of only 3% of the drinking outcome at follow-up could be attributed to treatment. However this effect appeared to be present at week one before most of the treatment had been delivered. The zero treatment dropout group showed great improvement, achieving a mean of 72 percent days abstinent at follow-up. Effect size estimates showed that two-thirds to three-fourths of the improvement in the full treatment group was duplicated in the zero treatment group. Outcomes for the one session treatment group were worse than for the zero treatment group, suggesting a patient self selection effect. Nearly all the improvement in all groups had occurred by week one. The full treatment group had improved in PDA by 62% at week one, and the additional 11 therapy sessions added only another 4% improvement.ConclusionThe results suggest that current psychosocial treatments for alcoholism are not particularly effective. Untreated alcoholics in clinical trials show significant improvement. Most of the improvement which is interpreted as treatment effect is not due to treatment. Part of the remainder appears to be due to selection effects.

Measuring residual functional capacity in chronic low back pain patients based on the dictionary of occupational titles

Study Design. This study designed and tested a functional battery based on the Dictionary of Occupational Titles (DOT). Objectives. Such a battery can be used to measure residual functional capacity (RFC) in chronic pain patients (CPP) and results can be matched against the demand minimum functional capacities (DMFC) of DOT jobs. Summary of Background Data. Physicians have difficulty translating medical impairment into functional limitation and thereby establishing the RFC of CPPs. Methods. The DOT, a USA government publication, provides information about physical demands of every USA job according to 36 factors and subfactors. The authors defined and developed a fuctional battery based on these factors/subfactors. This battery was tested on 67 consecutive CPPs to determine the percentage of CPPs able to pass specific job factors and the full battery and return to some DOT job, and evaluated the effects of pain on battery performance. The data were factor analyzed. Results. The battery determined if CPPs could perform DOT job factors and had the necessary RFC to be placed in a DOT job. The vast majority of CPPs could not pass the full battery and the presence of pain and original job classification predicted whether a CPP could perform a job factor. Factor analyses grouped the factors into four independent categories supporting the design of the battery. Conclusion. The battery can assess whether CPPs are able to return to work.

Functional capacity and residual functional capacity and their utility in measuring work capacity.

OBJECTIVE The pain physician is often asked to establish the medical impairment of the chronic pain patient (CPP) and from that determination ascertain the work capacity of the CPP. Functional capacity (FC) testing has recently been introduced as a more objective and accurate way of facilitating the determination of work capacity. However, there are conceptual problems with the measurement of FC. These will be reviewed and the relationship of FC to residual functional capacity (RFC) will be determined. Finally, a method for measuring RFC in a job-specific manner will be suggested. DATA SOURCES The literature in reference to the measurement of medical impairment, FC, and RFC was reviewed. STUDY SELECTION Studies appropriate to the objective of this review were selected for inclusion. CONCLUSIONS The FC and RFC are poorly defined. Lack of definition has interfered with design of appropriate test batteries specific to work capacity. To circumvent this problem a job-specific RFC measurement method is suggested. This method is based on the Dictionary of Occupational Titles.

Is there a relationship between nonorganic physical findings (Waddell signs) and secondary gain/malingering?

This is a structured evidence based review of all available studies addressing the concept of nonorganic findings (Waddell signs) and their potential relationship to secondary gain and malingering. The objective of this review is to determine what evidence, if any, exists for a relationship between Waddell signs and secondary gain and malingering.Waddell signs are a group of 8 physical findings divided into 5 categories, the presence of which has been alleged at times to indicate the presence of secondary gain and malingering. A computer and manual literature search produced 16 studies relating to Waddell signs and secondary gain or malingering. These references were reviewed in detail, sorted, and placed into tabular form according to topic areas, which historically have been linked with the alleged possibility of secondary gain and malingering: 1) Waddell sign correlation with worker compensation and medicolegal status; 2) Waddell sign improvement with treatment; 3) Waddell sign correlation with Minnesota Multiphasic Personality Inventory validity scores; and 4) Waddell sign correlation with physician dishonesty perception. Each report in each topic area was categorized for scientific quality according to guidelines developed by the Agency for Health Care Policy and Research. The strength and consistency of this evidence in each subject area was then also categorized according to Agency for Health Care Policy and Research guidelines. Conclusions of this review were based on these results. There was inconsistent evidence that Waddell signs were not associated with worker’s compensation and medicolegal status; there was consistent evidence that Waddell signs improved with treatment; there was consistent evidence that Waddell signs were not associated with invalid paper-pencil test; and there was inconsistent evidence that Waddell signs were not associated with physician perception of effort exaggeration. Overall, 75% of these reports reported no association between Waddell signs and the 4 possible methods of identifying patients with secondary gain and/or malingering.Based on the above results, it was concluded that there was little evidence for the claims of an association between Waddell signs and secondary gain and malingering. The preponderance of the evidence points to the opposite: no association.

What is the quality of the implemented meta-analytic procedures in chronic pain treatment meta-analyses?

OBJECTIVE Meta-analysis (MA) is the application of quantitative techniques for the purposes of summarizing data from individual studies. This type of review has many advantages over traditional reviews. However, different investigators performing MAs on the same data set have reached different conclusions. These reliability problems have been attributed to differences in the quality of the implemented meta-analytic procedures. We, therefore, examined the chronic pain treatment meta-analytic literature for MA procedure quality and for the consistency of conclusions. DESIGN, SETTING, PARTICIPANTS, OUTCOME MEASURES: Chronic pain treatment MAs were isolated according to inclusion/exclusion criteria. Data from these MAs were abstracted into structured tables. Table format reflected eight meta-analytic procedures identified previously as being important to MA implementation quality. These were: adequacy of retrieval, publication bias, inclusion/exclusion criteria, abstraction of data, quality, homogeneity/heterogeneity, independence, and statistical versus clinical interpretation. Each meta-analytic procedure was then independently rated by two raters. Rating results were then analyzed by procedure for each individual MA for percentage scores out of 100%, and mean scores. For MAs addressing the same topic area (pain facility treatment, antidepressant treatment, manipulation treatment) direction of effect size was noted. Mean effect sizes were calculated for these subgroups. RESULTS Sixteen chronic pain treatment MAs fulfilled inclusion/exclusion criteria. Mean procedure ratings indicated that four procedures may not be implemented adequately. These were publication bias, abstraction of data, quality, and homogeneity/heterogeneity. There was wide MA implementation score variability, with 37.5% scoring less than 50%. The effect sizes of the MA subgroups demonstrated replicate nonvariability. CONCLUSIONS Some meta-analytic procedures could be interpreted to be implemented inadequately in some chronic pain treatment MAs. There is wide variability between individual chronic pain treatment MAs on adequacy of implementation of these procedures. However, the effect sizes of the different MA subgroups demonstrated consistency. This finding indicates that for these MA subgroups, MA results are consistent between authors. In addition, chronic pain MAs, as compared with other groups of MAs, appear to address some of the procedures in a more adequate fashion. Future chronic pain MAs should concentrate on improving the quality of their methods with particular emphasis on the above four procedures. Because of potential validity problems with these results, these data cannot and should not be used to make administrative decisions about previous MAs.