Spine

Issue: Volume 22(17), 1 September 1997, pp 2016-2024 Copyright: (C) Lippincott-Raven Publishers. Publication Type: [Functional Restoration] ISSN: 0362-2436 Accession: 00007632-199709010-00016 Keywords: compensation, disability, litigation, low back pain, rehabilitation

[Functional Restoration]

The Effect of Compensation Involvement on the Reporting of Pain and Disabilityby Patients Referred for Rehabilitation of Chronic Low Back Pain

Rainville, James MD*+; Sobel, Jerry B. MD*; Hartigan, Carol MD*+; Wright,Alexander MD*++

Author InformationFrom *the New England Spine Care Center, Chestnut Hill, Massachusetts, and theDepartments of +Rehabilitation Medicine and ++Orthopedic Surgery, TuftsUniversity Medical School, Boston, Massachusetts.

Acknowledgment date: May 13, 1996.

First revision date: December 2, 1996.

Acceptance date: March 13, 1997.

Device status category: 1.

Address reprint requests to: James Rainville, MD; New England Spine CareCenter; 830 Boylston Street; Chestnut Hill, MA 02167.

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Outline

Abstract

Materials and Methods

Results

Comparisons of Presenting Characteristics of All Study Subjects

Treatment Recommendations, Compliance, and Compensation Involvement

Comparisons of Patients Completing Spine Rehabilitation

Discussion

References

Abstract

Study Design. In this prospective, observational, cohort study of 192individuals with chronic low back pain, the group of individuals was dividedbased on compensation involvement, and their presentation pain and disability, treatment recommendations, and compliance were compared. For 85 of theseindividuals who completed a spine rehabilitation program, their pain anddisability at 3 and 12 months were compared.

Objectives. To test the theory that individuals with compensation involvementpresented with greater pain and disability and would report less change of painand disability after rehabilitation efforts.

Background. Previous studies have produced conflicting results concerning thisissue.

Methods. Individuals were recruited as consecutive patients referred forconsultation at a spine rehabilitation center. Pain, depression, and disabilitywere assessed using self-report questionnaires at evaluation and at 3 and 12months. Rehabilitation services consisted of aggressive, quota-based exercisesaimed at correcting impairments in flexibility, strength, endurance, andlifting capacity, identified through quantification of back function. Multifactoral analysis of variance models were used to control for baseline differencesbetween compensation and noncompensation patients during analysis of targetvariables.

Results. The compensation group included 96 patients; these patients reportedmore pain, depression, and disability than the 96 patients without compensationinvolvement. These differences persisted when baseline differences werecontrolled for with multifactoral analysis of variance models. Treatmentrecommendations and compliance were not affected by compensation. For patientscompleting the spine rehabilitation program, length of treatment, flexibility,strength, lifting ability, and lower extremity work performance before andafter treatment and patient satisfaction ratings were similar for the compensation and non-compensation groups. At 3 and 12 months, improvements indepression and disability were noted for both groups, but were statistically

and clinically less substantial for the compensation group. At the 12 monthfollow-up visit, pain scores improved for the noncompensation group, but notfor the compensation group.

Conclusions. In chronic low back pain, compensation involvement may have anadverse effect on self-reported pain, depression, and disability before andafter rehabilitation interventions.

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Most experienced clinicians report a degree of pessimism when encounteringpatients with chronic low back pain seeking or receiving compensation becauseof their symptoms. Compared with noncompensation patients with similarpathology, these patients seem to respond less well to interventions.

Previous medical research has supported the notion that compensation involvementadversely influences the report of pain and disability, as well as outcomesfrom treatments.4,5,16,19,21,23-26,43,44 Other studies have suggested thatthose involved with compensation do not report increased pain or disability andrespond appropriately to treatments.1,7,12,15,31,32,40,42 The recruitment sitesof these studies have varied and include inpatient services, anesthesia and multidisciplinary pain clinics, outpatient physician practices, and rehabilitation services.1,4,5,7,16,19,21,23,25,27,31,40,42,43 Useful conclusions about thissubject remain unclear.

Analysis of the demographics of patients referred to the authors' spinerehabilitation center revealed that nearly equal numbers of compensation andnoncompensation patients presented for evaluation and treatment of chronic lowback pain symptoms. The authors' had observed significant improvement inmeasures of flexibility and strength and self-reported disability in a priorsetting in which they were exclusively treating patients receiving compensationand using a functional restoration approach.35,36 Improvements also were notedin patients' pain attitudes and beliefs, but despite all of these areas ofpositive outcomes, reports of pain did not show any consistent improvement.36One had to wonder if pain symptoms had actually lessened, but that reinforcementsfor reporting pain within compensation systems had made patients reluctant toreport any improvements. In the current setting, compensation and noncompensation patients are mixed in a spine rehabilitation program. Therefore, this was anideal site for observing potential differences between patients' presentingcharacteristics and treatment outcomes based on compensation status.

This prospective, observational study was conducted to explore whether patientspresenting for evaluation and treatment of chronic low back pain differ, basedon compensation status, in their report of pain and disability. The authorsalso were interested in whether compensation involvement affected treatmentrecommendations, compliance, and responsiveness to rehabilitation efforts at 3

and 12 month follow-up visits. The authors theorized that compensation involvement had a negative influence on the above areas. Materials and Methods

Subjects. One hundred ninety-two consecutive patients with primary symptoms ofchronic (duration > 4 months) low back pain and/or sciatica evaluated by aphysicians at this center between October 1, 1993 and February 28, 1994 wereentered into a prospective data base if they: 1) were between the age of 18 and70 years, 2) had no surgically correctable lesion as the cause of low back painor were not interested in pursuing surgical options, 3) were at least 3 months postdiscectomy or 6 months postfusion, 4) possessed reading and writingcomprehension of the English language, and 5) had no concurrent medical illness(cardiopulmonary, central nervous system, etc.) that produced significantdisability. Eighty-seven percent of patients were referred by physicians ormedical case managers, and the remaining 13 percent were self-referred.

Patients who were receiving or seeking financial compensation because of theirback pain were defined as having compensation involvement. This includedpatients receiving Workers' Compensation, Social Security Disability, orprivate disability policy benefits, or patients who were the plaintiff in anunsettled personal injury suit. Ninety-six of the 192 study subjects wereinvolved with one or more of these areas of compensation, and 96 were not. Thetypes of compensation involvement are summarized in Table 1.

Of the 192 patients, 38 were evaluated only and did not receive any furthertreatment. Three required advice only, seven were not interested in participatingin any recommended treatment secondary to travel distance, 21 were notinterested in pursuing recommended treatment options, and seven were deniedinsurance authorization for further treatment. Twenty-three of the patients whowere evaluated but received no treatment had compensation involvement, and 15did not.

The 154 remaining patients were referred to physical therapy for treatment oftheir chronic back pain syndromes. Thirty-seven of the 154 patients had minimaldisability and were referred only for the development of independent backexercise programs. Six of these patients had compensation involvement. Theremaining 117 patients had moderate to severe disability and were referred to aspine rehabilitation program. Of these, 67 had compensation involvement. Forthose referred to the spine rehabilitation program, 32 (27%) dropped out of thetreatment program; 20 of these patients (30%) had compensation involvement.Reasons for discontinuing treatment included medical illnesses for sixpatients, conflicts with work schedules for two patients, and lack of interestin the treatment approach for 24 patients.

Eight-five patients completed the spine rehabilitation program, 47 of whom hadcompensation involvement. These patients who completed the treatment program

will be the focus of the treatment outcome portion of this report.

Paper and Pencil Measures. At the initial evaluation, all patients completed aquestionnaire that inquired about demographic variables, symptoms, diagnostictests, prior treatments, compensation involvement, and work status. Self-reporteddisability was measured with an Oswestry Disability Questionnaire (OSWESTRY)with potential scores ranging from 0 (no disability) to 100 (severe disability).9The intensity of pain was measured by 10-cm visual analog scales anchored with0 (no pain) and 10 (worst possible pain) for back (BACK-VAS) and leg (LEG-VAS)pain symptoms.14 Depression symptoms were measured by the Beck DepressionInventory (BDI) with a range of scores from 0 (no depression) to 63 (severedepression).2

Patient satisfaction was assessed with a 10-item questionnaire with potentialresponses of 1 (excellent), 2 (very good), 3 (good), 4 (fair), and 5 (poor).Questions assessed scheduling, business services, physician services, therapist services, team-work, communication, education, home exercise instruction,quality of care, and effectiveness of care. Responses to the 10 questions weretotaled with a range of scores from 10 to 50.

Follow-up Questionnaires. Three months after the initial evaluation, a researchassistant mailed a follow-up packet to all patients. Packets included anOSWESTRY, BDI, BACK-VAS, LEG-VAS, and a Patient Satisfaction Questionnaire.Twelve months after the initial evaluation, another follow-up packet was mailedto all patients in the study. Packets included a stamped return envelope. If noresponse was received in 3 weeks, a second packet was mailed. After 3 moreweeks, phone calls (maximum of three) were placed to all nonresponding patients. If contacted, patients were given the options to complete the questionnaires onthe phone. When not at home, instructions were left with household members oron answering machines to contact the research assistant or to complete themailed questionnaires.

Quantification of Physical Function. Trunk flexibility, straight leg raising, trunk strength, lifting ability, and lower extremity work endurance werequantified before and at the completion of spine rehabilitation.

Maximum trunk flexion and extension in the standing posture was measured with asingle inclinometer (AngleLevel, Dejon Tool Co, Covington, OH) placed over theT12 spinous process.37 Maximum straight leg raising (SLR) was measured byplacing the inclinometer over the bony surface just below the tibial tuberosityand raising the leg until significant back or leg pain occurred or until thepelvis was observed to rotate.22,28

Trunk extension strength was quantified using Cybex back extension exerciseequipment (Lumex Corp., Ronkonkoma, NY). The testing procedure used a four-repetition to maximum-weight-successfully-lifted protocol that is described in detail

elsewhere.41

Lifting ability was evaluated using the progressive isoinetrial liftingevaluation (PILE) described by Mayer et al.30 The maximum weight lifted forfour repetitions from floor to waist was recorded as lumbar PILE, and thatlifted from waist to shoulder was recorded as cervical PILE.

To correct for anthropomorphic differences between patients, maximum backstrength and PILE weights were converted into percent ideal body weight beforedata analysis. Ideal body weight was calculated for patients by measuringheight and actual weight and estimating body type and comparing thesemeasurements with those on standardized, sex-specific charts.33

Lower extremity work performance was quantified using a 9-minute protocol on anisokinetic exercise bicycle (Cybex Fitron, Lumex Corp., Ronkonkoma, NY) duringwhich kilogram-meters (kg-m) per minute of work were recorded.41

Treatment. The spine rehabilitation program uses exercise to eliminateimpairments in flexibility, strength, endurance, and lifting capacity. Theoccurrence of pain with exercises was expected, and the patients wereencouraged to work through pain symptoms to complete the established exercisequota. Exercise quotas were increased throughout treatment. Treatments occurred in groups consisting of a maximum of eight patients and were led by a physicaltherapist and an exercise physiologist. Behavioral techniques were used topromote wellness behaviors (exercise) and to extinguish pain behaviors(limping, moaning, declining to perform exercises, etc.). Hands-on treatmentsand applied modalities were not offered. Nonsteroidal anti-inflammatory andantidepressant medications were prescribed at the discretion of the evaluatingphysician, but narcotic analgesics were not prescribed, and their use wasdiscouraged. Referrals for psychological counseling occasionally wererequested.

The first week of treatment included a comprehensive physical therapyevaluation, quantification of physical function, instruction in a homestretching program, and orientation to the treatment facility.

Patients then were enrolled in a Level 1 treatment group that consisted of 2hours of physical therapy three times per week. Sessions included 1 hour ofstretching and 1 hour of exercise on strengthening and endurance equipment.Strengthening equipment included Cybex Eagle Strength System (Lumbex Corp.,Ronkonkoma, NY) back extension, rotary torso, multihip, and lat pull-downmachines, Roman chair (back hyperextension), PILE lifting station, dumb bells,and theraband. Endurance equipment included isokinetic bicycles (Cybex Fitron,Lumbex Corp., Ronkonkoma, NY) and upper body ergometer (Cybex UBE, LumbexCorp., Ronkonkoma, NY). Initial strength, lifting, and endurance exercise levels were based on evaluation test results. Patients usually attended five or

six Level I sessions.

Patients then entered Level II, where group sessions were increased to 2 hoursand 45 minutes and occurred three times per week. These sessions included 45minutes of stretching, 1 hour of strengthening, and 1 hour of aerobic training(including low-impact step aerobic exercise). Requantification of physical function was performed biweekly and at the completion of treatment. Compliance,behavioral problems, and treatment goals were discussed at biweekly teamconferences between therapists and physicians. In general, 5 weeks of Level IIwas projected for patients, with a total treatment time averaging 8 weeks.

At discharge, all patients in the study received individualized, writtenrecommendations for exercise routines that were to be performed at home and/ora fitness facility.

Statistical Methods. Statistical analyses were performed using SPSS statisticalsoftware for personal computers (SPSS, Chicago, IL). Summary statistics werecomputed. Comparisons between those with and without compensation involvementwere done using chi-square tests for nominal variables and independent-sample ttests for ordinal, interval, and ratio values.

Multivariate analysis of variance (MANOVA) techniques were used to determinewhether compensation involvement maintained its effect on self-reported painand disability when other differing characteristics were controlled. The firststep was to use multiple regression analyses, correlations, and two-way ANOVAequations to identify cofactors and variables that had significant influence onBACK-VAS, LEG-VAS, and OSWESTRY. These cofactors and variables then were entered into MANOVA equations, which included compensation involvement as a cofactor.

Chi-square and discriminant analyses were used to explore the relationships ofcompensation involvement with treatment recommendations and compliance.Paired-sample t tests were used to compare physical function results at thebeginning and at the end of spine rehabilitation and questionnaire scores atevaluation with scores at 3 and 12 month follow-up visits. Results Comparisons of Presenting Characteristics of All Study Subjects

For the entire cohort of 192 patients, substantial differences were noted inmany demographic, subjective, and objective characteristics when patients werecompared based on compensation involvement (Table 2). On average, those withcompensation involvement were less educated, were more likely to work jobs withmedium or heavy labor, were more likely to relate a compensatable event to theonset of symptoms, had more reports of leg pain, had more neurologic signs andsymptoms, were less flexible, and were more likely to report pain with trunkmovements and straight leg raising. They also reported higher levels of pain,depression, and disability. These findings suggest that patients with

compensation involvement had more serious chronic back pain syndromes.

Further analyses identified depression (BDI), education, and age as variablesthat might influence the differences in initial pain scores (BACK-VAS andLEG-VAS) between patients with and without compensation involvement. Thesevariables were entered into MANOVA equations with compensation involvement as afactor and BACK-VAS, then LEG-VAS as the dependent variables. The resultsindicated that compensation involvement maintained a strong influence onBACK-VAS scores (F = 12.67, df = 1, P P P Treatment Recommendations, Compliance, and Compensation Involvement

Chi-square analysis revealed that compensation involvement was not associatedwith membership in the evaluation only group. Discriminant analysis revealedthat referral to an individual physical therapy program was determined mainly by the characteristics of low OSWESTRY and BDI scores, mild impairments in trunk flexibility, and lack of work disability (Wilks Lambda = 0.728, P

Chi-square analysis revealed that treatment compliance for the spine rehabilitationprogram did not differ based on compensation involvement. The drop-out groupdemonstrated higher mean scores for OSWESTRY (57 vs. 42, t value = 4.6, P vs.5.9, t value = 2.36, P = 0.02), and age (45 vs. 39 years, t value = 2.22, P =0.03). The drop-out group contained a greater percentage of patients who hadfailed pain programs (29% vs. 10%, chi-square = 3.9, df = 1, P = 0.05) and whoused muscle relaxants (31% vs. 11%, chi-square = 7.8, df = 1, P = 0.005). Otherdemographics, symptoms, prior treatments, physical examination findings, andquantified physical capacities were similar for the drop-out and treatmentgroups. Comparisons of Patients Completing Spine Rehabilitation

Baseline Characteristics. Baseline characteristics of spine rehabilitationpatients were compared based on compensation involvement and are presented inTable 3. Differences between patients were noted for BACK-VAS, LEG-VAS, BDI,OSWESTRY, education, job categories, work disability, time of work loss, andevent-related onset of symptoms similar to those found for the entire studypopulation.

Treatment Duration. Mean time from evaluation to treatment completion wassimilar for those with and without compensation involvement (7.9 vs. 8.5 weeks,P = NS).

Physical Impairments. Initial and final performances on tests of physicalfunction for patients with and without compensation involvement are presentedin Table 4. Similar results were noted for trunk extension, back strength,lifting ability, and endurance at initial and postrehabilitation testing. Thegroup with compensation involvement had statistically less trunk flexion andstraight leg raising at initial evaluation and at treatment completion. Further

analyses using MANOVA revealed that the differences in initial trunk flexionresulted from baseline differences in BACK-VAS (F = 11.16, df = 1, P = 0.001)and frequency of reported pain with flexion (F = 15.35, df = 1, P = 0.000) andnot from compensation involvement. Similarly, MANOVA revealed that differencesin final trunk flexion resulted from differences in trunk flexion at the onsetof treatment and on BACK-VAS at 3 months. Results from MANOVA analyses ofstraight leg raising also revealed that baseline differences of variables otherthan compensation involvement accounted for all differences between groups.

At completion of the spine rehabilitation program, similar improvements wereobserved for all areas of physical function for both groups.

Response to Follow-up Questionnaires. Overall, 88% of those completing the spine rehabilitation program responded to the 3-month questionnaires. For thosewithout compensation involvement, 95% responded, and for those with compensationinvolvement, 83% responded. The response rate for the 12-month questionnairewas 73%, with 79% of the noncompensation group and 68% of the compensationgroup responding. These differences in response rates did not reach statisticalsignificance.

Subjective Measures. Results of pencil and paper measures at evaluation, 3months, and 12 months are reported in Table 5. Less disability and depression was noted at the 3 and 12 month follow-up visits for both groups. Improvementwas noted for back pain in both groups at 3 months, but at 12 months,improvement was noted only for the group without compensation involvement.Improvement in leg pain symptoms only reached statistical significance for thenoncompensation group at 3 months. Noncompensation patients reported less pain,depression, and disability at all points of follow-up assessment.

The magnitude of change in pain and disability between evaluation and 3 monthsand between evaluation and 12 months were calculated, and these scores wereconverted to percent of change of the initial scores. The percents of changefor BACK-VAS, LEG-VAS, and OSWESTRY then were compared based on compensationstatus. For pain measures, differences in the percentages of change did notreach statistical significance between groups. The compensation groupdemonstrated a lower percent change of OSWESTRY at 3 months (54% vs. 25%, t =3.33, df = 66, P = 0.002) and at 12 months (55% vs. 25%, t = 2.51, df = 60, P =0.015). The negative influence of compensation status on these differences inpercent change of OSWESTRY scores persisted when differences in presentingscores were controlled for using MANOVA.

Mean responses to all items of the satisfaction questionnaire were similar,with total score means of 16.4 for those without compensation involvement and16.7 for those with compensation involvement. Discussion

Patients referred to a rehabilitation practice with chronic low back pain whohad compensation involvement differed from patients with no such involvement.Compensation patients were younger, less educated, reported occupations withheavier labor, had more prior therapy, and had more severe pain-relatedimpairments in flexibility. Compensation patients reported more pain and othersubjective symptoms, were more depressed, and reported more disability. Thesedifferences in pain and disability were present even after differences in otherbaseline variables were controlled for in multivariate analyses and persistedthroughout the follow-up year. This suggests that compensation involvement mayhave an adverse effect on the reporting of pain and disability. These resultssupport the common perception that compensation patients often have more severechronic low back pain syndromes and therefore represent more difficultchallenges for clinicians.4,5,16,21,24-26,38

Rehabilitation recommendations about intensity of the therapy services mainlywere influenced by initial disability (including work absence) and depression.For the noncompensation group, nearly one third of patients fell into thecategory of mild disability and depression and were referred for brief therapyinterventions. In contrast, only infrequently did patients involved withcompensation have mild disability and depression, and therefore few weredetermined appropriate for these same brief interventions. It is not clear whycompensation patients with mild disability were so scarce in this survey. Thismay represent a bias of the referring physicians or case managers, who may notrefer for rehabilitation as many patients with chronic low back pain involved with compensation with mild disability as they do noncompensation patients withsimilar symptoms. An alternate consideration might be that involvement withcompensation causes patients to cluster in terms of subjective symptoms andaccess to medical care. Those who express severe disability (and workintolerance) may be encouraged to maintain involvement in the medical caresystem, whereas those with mild disability (and therefore working) may bediscouraged from seeking further medical care.

Treatment compliance with the spine rehabilitation program did not differ basedon compensation status. The authors believe that the reasons for discontinuingtreatment usually were based on a misalignment of outcome expectations betweenpatients and the treatment staff. Usually, noncompliant and drop-out patientswere not interested in improving physical function unless their pain symptomsfirst improved, and the treatment staff stressed that the primary focus oftreatment would be directed at improving physical function, with a secondaryfocus on reducing pain. Obviously, the ability (or inability) to aligntreatment goals introduced a strong bias for the reporting of treatment resultsfrom this observational study, because a substantial portion of evaluated patients were not interested in and did not comply with treatment recommendations. Reporting this compliance data, however, allowed the authors to present arealistic picture of the acceptability of aggressive spine rehabilitation topatients with chronic low back pain, especially since participation in such

treatment was elective. It was important to recognize that these difficultiesin aligning treatment expectations and treatment compliance were independent ofcompensation involvement.

Compensation status did not influence the pretreatment or posttreatmentmeasurements of physical function in those patients who completed the groupspine rehabilitation program nor the length of the treatment programs. Theseresults support the work of others who have demonstrated that tangible changesare observed after rehabilitation focused on improving quantifiable physicalfunctional in the presence of chronic resistant low back pain.1,20,29,34,35,44 These measurable results reinforce the efforts of the patients and therehabilitation teams and may offer encouragement to patients in the face of anotherwise stagnant pain and disability predicament.

The theory underlying this type of spine rehabilitation stresses that theimprovements in physical function acquired by working through chronic painsymptoms will build confidence for improving performances of other dailytasks.11 This should result in a lessening of disability.20,29,36 This study didobserve lessening in disability at 3 and 12 month follow-up visits forcompensation and noncompensation patients who had undergone group spinerehabilitation. Despite similar improvements in flexibility and strength, however, those patients with compensation involvement were observed to have less reduction in disability scores, even when baseline differences were controlled.Similar observations have been noted by others.4,5,8,18,19,25,43 This suggeststhat some factors common to compensation patients make them less receptive tointerpreting improved physical capacities as enabling improved daily functioningas opposed to noncompensation patients with similar back pain symptoms. Thoughmultiple factors have been identified that can increase back pain-relateddisability, such as decreased education, strong pain beliefs, and workrelatedissues, the heightened disability and the resistance to changing of that disability by those involved in compensation suggest that disability may bestrongly reinforced by involvement in the compensation system itself.3,6,12,27,36,39

Depression symptoms were observed to improve at 3- and 12-month follow-upvisits. This may reflect improvement in mood resulting from re-establishingdesired activities, because depression and disability remained strongly relatedthroughout the study period.45 Importantly, depression was greater for thoseinvolved with compensation throughout the study period. This observation hasbeen noted in previous studies and may be strongly influenced by depressionassociated with work disability within the compensation group.10,17,19,24

Observations of the noncompensation patients suggest that improvements in backfunction were followed by an overall improvement in back pain symptoms.Unfortunately, despite similar improvements in back function, persistentimprovement in pain was not noted for the compensation patients. These resultswere similar to those reported in prior studies.13,19,35,43 The authors of the

present study cannot explain why changes in pain after identical treatmentnoted for the noncompensation patient were not reported by the compensationgroup. As with perceived disability, it is possible that patients withlong-term compensation involvement have had their pain symptoms so stronglyreinforced by the benefits of that compensation involvement that they arereluctant to report improvement regardless of the treatment used.16,42,43 Thisreinforcement could include a financial disincentive of losing benefits orremoval of excused work absence if the perception of pain and disabilityimprove. Similar findings have been reported for carefully selected patients for discectomy treatment of disc herniations with and without compensationinvolvement.23

The authors conclude that it is difficult to consistently improve chronic painand disability in patients involved with compensation, regardless of themedical intervention used. Though changes in the social, political, and legal environments that lessen the reinforcements for subjective reports of pain anddisability may occur in the future, at present, health care providers shouldcontinue to move toward focusing on objective, rather than subjective, measuresof outcome for this group of patients. References

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Key words: compensation; disability; litigation; low back pain; rehabilitation

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