Volume 90, Issue 4 , Pages 545-552, April 2009
Preventing Progression to Chronicity in First Onset, Subacute Low Back Pain: An Exploratory Study
Article Outline
Abstract
Slater MA, Weickgenant AL, Greenberg MA, Wahlgren DR, Williams RA, Carter C, Patterson TL, Grant I, Garfin SR, Webster JS, Atkinson JH. Preventing progression to chronicity in first onset, subacute low back pain: an exploratory study.
Objectives
To evaluate the effects of a behavioral medicine intervention, relative to an attention control, in preventing chronic pain and disability in patients with first-onset, subacute low back pain (LBP) with limitations in work-role function.
Design
A 2-group, experimental design with randomization to behavioral medicine or attention control groups.
Setting
Orthopedic clinic at a Naval Medical Center.
Participants
Sixty-seven participants with first-onset LBP of 6 to 10 weeks of duration and impairment in work function, of whom 50 completed all 4 therapy sessions and follow-up 6 months after pain onset.
Intervention
Four 1-hour individual treatment sessions of either behavioral medicine, focused on back function and pain education, self-management training, graded activity increases, fear reduction, and pain belief change; or attention control condition, focused on empathy, support, and reassurance.
Main Outcome Measures
The primary outcome was proportion of participants classified as recovered, according to pre-established clinical cutoffs on standardized measures, signifying absence of chronic pain and disability at 6 months after pain onset. Secondary analyses were conducted on pain, disability, health status, and functional work category. Intervention credibility and pain belief manipulation checks were also evaluated.
Results
Chi square analyses comparing proportions recovered at 6 months after pain onset for behavioral medicine and attention control participants found relative rates of 52% versus 31% in the modified intent-to-treat sample (P=.09) and 54% versus 23% for those completing all 4 sessions and 6-month follow-up (P=.02). At 12 months, 79% of recovered and 68% of chronic pain participants still met criteria for their respective groups (P<.0001). Recovered participants also had higher rates of functional work status recovery at 12 months (recovered: 96% full duty and 4% light duty; chronic pain: 61% full duty, 18% light duty, and 21% medical discharge, respectively; P=.03).
Conclusions
Early intervention using a behavioral medicine rehabilitation approach may enhance recovery and reduce chronic pain and disability in patients with first-onset, subacute LBP. Effects are stronger for participants attending all 4 sessions and the follow-up assessment.
Key Words: Behavioral medicine, Health status, Pain, Preventive health services, Rehabilitation
List of Abbreviations: BMI, body mass index, DDS, descriptor differential scale, LBP, low back pain, PAIRS, pain and impairment relationship scale, QWB, quality of well-being, SIP, sickness impact profile
LOW BACK PAIN is among the nation's most costly medical conditions,1 with direct costs exceeding $26.3 billion.2 LBP is the fifth most common reason US patients consult physicians and the second most frequent health problem in primary care.3, 4 Although most patients with acute LBP recover within 4 to 6 weeks,5 those who do not account for the bulk of individual and economic burden.6 Prevention is therefore a public health research priority.7
Patients with acute (less than 3 months), subacute (6–12 weeks), and chronic (at least 3 months) LBP exhibit different physiologies, courses, and treatment responses.8 The subacute phase has been recommended as an optimal intervention window.9 A previous study prospectively examined patients with first-onset LBP of 6 to 10 weeks and found that 78% had daily pain and disability after 6 months, and 72% had these symptoms after 1 year.10
Psychosocial variables, such as beliefs, moods, or coping, impact the transition from acute to chronic pain and disability in LBP11, 12, 13 and may exercise greater impact than biomedical or biomechanical variables.14 Therapies that target psychosocial factors have therefore been recommended in recent national clinical guidelines for back pain treatment.15 Group cognitive-behavior therapy for patients with LBP in primary care has reduced long-term disability and absenteeism relative to minimal and active controls.16, 17, 18, 19 These studies did not differentiate patients with subacute from chronic or acute conditions. Evidence suggests that psychosocial factors emerge as potent influences on chronicity development at the subacute stage,20 and that pain of this duration, unlike acute pain, is highly predictive of chronicity10; therefore, targeting subacute LBP specifically should maximize therapeutic impact.
Only a handful of psychosocial intervention studies have selected for subacute LBP. In a Norwegian study of patients sick-listed for 8 to 12 weeks,21 cognitive therapy improved disability at 18 weeks, whereas exercise reduced pain significantly but had higher dropout. A randomized study of disability applicants 4 to 8 weeks on compensation for back pain22 found physician consultation plus weekly telephone sessions, focused on increasing activity, reduced pain and disability 2-fold relative to usual care at 6 months, but did not increase return to work. An intervention focused on activity increase and fear reduction among sick leave patients with new or recurrent back pain of 4 to 12 weeks23, 24 resulted in improved 1-year return to work and 5-year employment and sick leave relative to usual care. These subacute LBP studies suggest the usefulness of psychosocial intervention yet are limited by either the use of usual care controls or a follow-up assessment interval of less than 6 months, and the use of subjects with previous pain episodes.
With this randomized, controlled pilot study, we sought to evaluate the efficacy of a behavioral medicine intervention relative to an attention control in preventing chronic pain and disability at 6 months in patients with first-onset, subacute LBP. Participants were recruited from a treatment-seeking sample in a closed health care system and had all been assigned to light duty status because of pain-related functional limitations at study onset. The intervention was based on established behavioral pain treatment models25 and emphasized self-management training, systematic graded activity increases, fear reduction, and pain belief change.
Nonspecific effects, including provider attention, expectations, and treatment believability, are threats to internal validity in clinical research studies.26 To address these concerns, this study used a nonspecific attention control, equated for number and duration of sessions, which provided active listening, empathy, support and nondirective assurance, including suggestion that the patient consult with the orthopedic team as needed to manage pain and recovery. As with the experimental arm, the attention control condition was also assessed for credibility and palatability. Therapists, patients, and assessors were not informed about the nature of alternative conditions or hypotheses, and treatment sessions were monitored to ensure fidelity to condition.
In line with previous work in categorizing both acute and chronic back pain27, 28 and using procedures for defining clinically significant change,29 we established cut scores for measures of pain and disability in patients with subacute LBP for the purposes of evaluating comparative treatment outcomes in clinically meaningful terms. Values below the cutoffs are considered statistically similar to 0, and these patients are classified as resolved, indicating the individual is like a member of a healthy population. The primary study outcome was the proportion of participants classified as resolved versus chronic pain at 6 months after pain onset. It was hypothesized that the behavioral medicine intervention would increase the proportion resolved relative to the attention control. Supplemental analyses examined the hypotheses of greater improvement in pain beliefs at 6 months in the behavioral medicine group relative to attention controls, and lower pain and disability, better health status, and less impairment in work function at follow-up in the resolved group relative to chronic pain.
Methods
Participants and Setting
The Committee on Investigations Involving Human Subjects and the Scientific Review Committee at the participating institutions approved this research protocol. Participants were identified through systematic review of patients seeking consultation at an orthopedic clinic in a closed health care system. Primary care physicians referred to orthopedic clinic patients whose back pain persisted for 4 to 6 weeks despite conservative care and who demonstrated impaired work function. With clinic permission, a research nurse approached patients with first-onset back pain of 4 to 10 weeks for consent to be evaluated for enrollment.
Study inclusion criteria were (1) age 18 to 50 years, (2) first-onset back pain (thoracic vertebra 6 or below) present daily for at least 6 but less than 10 weeks, (3) no other major medical illness or pain disorder, and (4) not a candidate for acute surgical intervention. Participants were excluded for (1) prior episodes of daily back or other pain lasting 1 week or longer, (2) being prescribed medications known to affect mood or function (eg, antidepressants, anxiolytics), (3) major surgery within the preceding 12 months, and (4) back pain secondary to serious medical disorder (eg, neoplastic disease, osteomyelitis, fracture).
Potential participants had to be able to attend the first intervention session within 1 week of group assignment to ensure the sample still represented a subacute pain phase. The research battery was administered promptly after informed consent and repeated 6 and 12 months after pain onset by research assistants not involved in other aspects of the study and blind to condition. Participants received their usual medical care during the study.
Usual Medical Care
Usual medical care was provided to both groups according to the Agency for Health Care Policy and Research Guidelines at that time.30 It consisted of 1 outpatient visit, which included (1) history, back examination, screening laboratory assessment for red flags; (2) discussion of physical findings; (3) a prescription for low-impact aerobic exercise; (4) general health recommendations; and (5) brief education regarding the benign natural history of back pain, and a Readers Digest article, “Good News for Bad Backs.”31 Follow-up visits occurred if requested or were indicated.
Behavioral Medicine Intervention
The experimental intervention was a modification of a behavioral medicine chronic pain program32, 33, 34 revised in pilot work to fit a subacute sample. It consisted of 4 weekly, 1-hour individual sessions, led by a master's-level clinician trained for the study in behavioral pain management and rehabilitation methods. Sessions followed a systematic protocol, which included instruction and demonstrations by the clinician, and take-home assignments and schedules (eg, exercise and activity). The overall course of treatment was based on (1) education about back function and pain, (2) systematic graduated increases in physical exercise to quota with feedback, (3) planning and contracting activities of daily living, (4) self-management and problem-solving training to cope with pain, (5) contingent reinforcement of active functioning and nonreinforcement of pain behaviors, and (6) vocational counseling, as needed. Session content was standardized as follows.
The first session reviewed the patient's history of back pain, treatment, and function and identified problem areas. The anatomy and physiology of back pain and use of analgesic medications were reviewed and educational articles provided. Cognitive constructs (eg, attitudes, perceived control) were explained. The patient's leading role in managing back pain care was emphasized: consultation with medical caregivers was recommended for red flag symptoms. Patients were taught to record antecedents (eg, actions, emotions) and consequences of pain (eg, excess disability), and the next week's self-monitoring diaries were distributed. Goals for physical reactivation were established.
In the second session, goals of self-monitoring and self-care were restated. Feedback from the educational articles was elicited, and the pain and function diary was reviewed. The major session focus was activity scheduling and setting individualized rehabilitation goals. The therapist led a problem-solving discussion of obstacles to achieving these goals and solutions and noted that progress toward quotas for physical rehabilitation would be reviewed and revised in subsequent sessions. The therapist trained the patient in a series of stretching and strengthening exercises. Finally, stress management and relaxation training concepts were introduced.
In the third session, assigned exercises were reviewed and additional stretching and muscle strengthening exercises taught. Barriers to exercise (eg, irregular work patterns, competing demands) were reviewed and alternative plans developed. Daily activity schedules and goals were evaluated, and help was offered as needed. Pacing of activities was discussed. The therapist instilled self-sufficiency in back care and confidence to overcome disability. Relaxation techniques were taught, and an audiotape and practice monitoring form were provided.
The fourth meeting entailed review of physical exercises, progress, activity goals, and relaxation practice. A second, abbreviated relaxation training audiotape was provided. Considerable time was spent reviewing the role of negative cognitions and interpersonal relationships in perpetuating pain and pain behavior. Situations likely to lead to lapses were forecast; patients were coached to avoid them, problem solve/plan, and return to their planned activities when lapses occurred. Work-related attitudes, demands, satisfaction, and vocational goals were reviewed. Use of analgesic medications was discussed, and adherence to medication schedules was reinforced.
Attention Control Condition
The attention control condition delivered nonspecific factors or unspecified therapeutic ingredients35 common to psychological therapies. These were social support, a therapeutic alliance, a plausible explanation for the patient's problem, and a credible rationale.
The attention control condition, equated for contact time, was delivered in 4 weekly, 1-hour individual sessions by a master's-level clinician with training in psychotherapy, and provided nondirective, supportive care, in contrast with the active, directive approach of the experimental treatment. Rogerian support techniques were used to build rapport, enhance comfort with one's situation, and facilitate inner direction to better health.36 The ingredients were (1) an active listening style, (2) gentle encouragement for activity without explicit quotas, (3) reassurance that “with time there would be healing,” (4) supportive, interested involvement, and (5) recommendation that the patient follow advice of the medical team. The patient took the lead in what was discussed. The therapist did not employ active suggestion, problem-solving, or behavioral or cognitive therapy techniques (eg, relaxation practice, cognitive restructuring).
The first session reviewed the patient's history of back pain, treatment, psychosocial background, and everyday functioning. In the next 3 sessions, the therapist reviewed the patient's pain and disability and discussed whatever important events were happening in the patient's life. Overall, the therapist encouraged the patient, attended to complaints of pain and their impact on function, and advised that medical caretakers were available for specific suggestions on symptoms or activity, and that the patient should follow their guidelines for return to function.
Booster Sessions and Fidelity Checks
Consistent with behavioral theory on maintenance of treatment gains,37 the protocol specified two 1-hour booster sessions to occur in the weeks immediately after therapy completion. In the behavioral medicine arm, the principles of treatment were reviewed, difficulties in implementation addressed by problem solving, and self-management skills and relapse prevention reinforced. In the attention control arm, the therapist continued to use a supportive, empathic approach to recovery from back pain. Each therapist delivered treatment in only 1 condition. To ensure fidelity, all treatment sessions in both conditions were recorded, and a psychologist with extensive experience in psychotherapy and cognitive-behavioral therapy for back pain (A.L.W.) reviewed the audiotapes.
Assignment and Masking
After qualification and baseline assessment, participants were randomly assigned to behavioral medicine or attention control conditions. To guard integrity of the blind, the code for group assignment was held by a separate research unit. Assessors and therapists were not told about the alternative treatments and hypotheses. Treatments were conducted in separate areas to prevent cross-talk.
Measures
PainThe 24-item DDS38 requires participants to rate current pain intensity and unpleasantness on 0 to 20 scales, relative to 24 descriptors. Items are averaged into an overall score. The DDS demonstrates good internal consistency, reliability, and validity, and its verbal pain intensity descriptors correspond to a wide range of pain magnitudes (eg, DDS intensity 6–7=very weak pain; 8=mild pain; 9=moderate pain; 10–11=slightly intense pain; 12–13=strong pain; >14=intense pain).38, 39
DisabilityThe 136-item self-report SIP40 evaluates interference with daily activities. The SIP total score (which ranges from 0–100) defines functional disability. Respondents indicated whether each limitation was experienced today because of back pain. Mean scores in patients with LBP41, 42 range from 10 to 20. Although there are some limits to the SIP's sensitivity,42, 43 it is a reliable and valid measure for patients with back pain.41, 44, 45
Health statusThe QWB interview46, 47 evaluates symptoms experienced in the preceding 4 days. It consists of 3 composite scores (physical activity, mobility, social activity) and a summary score, which ranges from 0 (death) to 1 (perfect health, no symptoms reported). Several studies support reliability and validity (see review48). Mean QWB scores of 0.615±0.5 are noted in treatment-seeking patients with chronic back pain.49
Pain beliefsThe 15-item PAIRS50 assesses pain beliefs and ability to function despite pain, with higher scores indicating greater functional restriction. A 7-point Likert rating scale assesses item agreement. The PAIRS has adequate internal consistency (α=0.82), is correlated with the SIP and observer ratings of physical limitations,50 and is validated for chronic back pain.51 Mean scores (±SD) in patients with chronic back pain attending a general orthopedic clinic (71.32±13.31) significantly exceeded those in demographically matched healthy controls (57.95±12.34).51
Functional work categoryMedical records were examined at study onset and follow-up for ratings of disability in work function. In a routine administrative action separate from the research project, each patient's physician rated physical fitness for duty, usually within 4 weeks of symptom onset, assigning the person to either light duty or full duty, based on ability to work at the person's usual job. Light duty indicated restricted activities and duties (eg, no heavy lifting, no running). Reassessment occurred 6 months after pain onset, at which time individuals could be rated as fit for full duty, continued for another 6 months on light duty, or given a medical discharge.
Potential confoundsThe Quebec Task Force Classification System for Spine Disorders52 is a clinical descriptive system based on history, orthopedic physical examination, and laboratory assessment. At entry, patients were classified into the following Quebec categories: pain without radiation; pain with proximal radiation; pain with distal radiation; pain with radiation and neurologic signs, muscle weakness, or diminished reflexes; and pain with root compression. BMI53 was calculated from height and weight using published nomograms to control for obesity, which is a risk factor for chronic LBP.54 A review of the medical record and a semistructured interview at study entry and exit documented concurrent treatments and medications. The interviewer requested, at each assessment point, the name and average daily dose of medications and types of treatments received (eg, analgesics, chiropractors).
CredibilityTreatment credibility and palatability were evaluated with a 6-item questionnaire.55 Participants rated treatment on a 6-point scale where 6 indicated “very much” and 1 indicated “not at all.” The items asked participants how believable the therapy was as an approach to back pain treatment, how likely it was to be effective, how willing they were to participate in the treatment, how much confidence they had in its success and in the therapist, and whether they would recommend the treatment to others.
Outcomes assessmentThe baseline battery was administered again 6 and 12 months after pain onset by research staff members who were blind to group assignment. The primary outcome was recovery, defined as both resolution of pain (measured by the DDS) and restoration of function (assessed by the SIP) at 6 months after pain onset. Outcome was defined rigorously in terms of both pain relief and enhanced daily functioning, because it is acknowledged that reducing pain intensity alone is clinically insufficient (eg, see reference19). Previous work, using well validated procedures29 and standardized measures with both subacute and chronic pain samples, empirically established a definition of recovery (eg, see references10, 27, 39). Low cut scores were identified a priori by creating confidence intervals differentiating patients from healthy controls for pain and disability outcome measures. Specifically, a DDS pain score below 6.8 and an SIP disability score below 3.0 are characteristic of a healthy population without pain; scores above these cut points are more characteristic of a pain population.27, 34, 39 Participants in this study were categorized as recovered (that is, as having no measurable pain or disability) if both DDS pain intensity and SIP disability were below these cutoffs at the 6-month follow-up, or as having chronic pain if either DDS or SIP scores were at or above cutoffs. To supplement this primary outcome, we also examined physicians' ratings of fitness for duty 6 months after pain onset.
Statistical Analysis
Power analyses were conducted based on our estimates of the proportion of participants expected to advance to chronicity in each group. Using figures from a previous study,10 we estimated that 78% of attention controls would be in the chronic pain category at 6 months. We anticipated, based on effect sizes shown in chronic pain interventions, that behavioral medicine would reduce chronic pain incidence by 30% to 40%. With 2 groups, a 2-tailed alpha level of .05, and numbers of 33 to 34 a group, the power of this study to find a significant between-group difference was .65 to .85.
The null hypothesis of no difference in proportion recovered between the treatment conditions was evaluated by a chi-squared contingency table. Given the exploratory purpose and small scale of this study, both a modified intent-to-treat analysis, assessing between-group differences in proportion recovered among all enrolled participants who completed the 6-month follow-up assessment (N=65), and a completer (N=50) analysis were planned a priori. We did not include the 2 participants (1 in each group) who completed 4 treatment sessions but not the 6-month follow-up in these analyses because we did not have any good data from which to estimate their 6-month recovery status. If we were to carry forward their baseline values, they would both of necessity be classified as having chronic pain based on the inclusion criteria; however, we rejected this approach, given that they chose to receive a full dose of either behavioral or attention control treatment. Noninclusion of these individuals should not have systematically biased the results in favor of one or the other condition, but could have slightly increased proportional estimates of recovery in both groups. Supplemental analyses were also conducted on participants who attended all 4 sessions and the 6-month follow-up (N=50) and the maximum dose sample who attended all 4 sessions and 2 boosters (N=32). All statistical analyses were 2-tailed.
Results
During a 2½-year period, 196 patients with first-onset back pain were identified, which represented approximately 6% of the 3629 patients with LBP evaluated in the orthopedic clinic. Figure 1 represents the flow of patients through the trial and final numbers for the samples analyzed. Table 1, Table 2 describe the baseline characteristics of participants. As expected, given the clinic setting, these were largely high school–educated, white, married men in their late 20s to mid-30s. Mean DDS pain intensity was “strong.”39 SIP total impairment in daily functioning was below the mean for patients in chronic pain treatment programs (eg, see reference42). All participants had been assigned to light duty status, also reflecting moderate functional impairment. Most experienced nonradiating back pain; 16% (11 of 67) had radiation accompanied by neurologic findings.
Fig 1.
Progress of participants through the trial. Participants identified as completing the trial attended all 4 sessions of behavioral medicine or attention control therapy and were assessed at follow-up 6 months after pain onset.
Table 1. Baseline Clinical Characteristics of Randomized Participants in Behavioral Medicine and Attention Control Conditions
| Characteristic | Behavioral Medicine n=34 | Attention Control n=33 | P Value |
|---|---|---|---|
| Education, y | 12.70±1.4 | 12.60±3.1 | .905 |
| Ethnicity, n (%) white | 23 (68) | 19(58) | .765 |
| Age, y | 28.90±6.8 | 32.20±8.3 | .078 |
| Sex, n (%) men | 28(82) | 30(91) | .305 |
| Marital status, n (%) married | 22(65) | 23(70) | .462 |
| Pain intensity(DDS) | 11.47±4.24 | 11.20±4.39 | .801 |
| Disability(SIP) | 11.40±7.69 | 12.26±8.80 | .669 |
| Life quality (QWB) | 0.57±0.060 | 0.57±0.050 | .762 |
| BMI, kg/m2 | 27.34(4.58) | 28.03(3.44) | .490 |
| Quebec Orthopedic Class, n(%) | .710 | ||
| Pain without radiation | 22(65) | 17(52) | |
| Pain, proximal radiation | 4(12) | 4(12) | |
| Pain, distal radiation | 4(12) | 5(15) | |
| Radiation and neurologic signs | 4(12) | 6(18) | |
| Nerve root compression | 0(0) | 1(3) |
Table 2. Baseline Clinical Characteristics of Participants Completing Treatment and Follow-Up in Behavioral Medicine and Attention Control Conditions
| Characteristic | Behavioral Medicine n=24 | Attention Control n=26 | P Value |
|---|---|---|---|
| Education, y | 12.8±1.6 | 12.7±2.5 | .866 |
| Ethnicity, n (%) white | 16(67) | 16(62) | .908 |
| Age, y | 28.8±7.1 | 32.9±7.9 | .094 |
| Sex, n (%) men | 20(83) | 23(89) | .602 |
| Marital status, n (%) married | 16(67) | 18(70) | .988 |
| Pain intensity(DDS) | 11.43±3.98 | 11.78±4.10 | .765 |
| Disability (SIP) | 12.94±7.77 | 12.73±9.29 | .929 |
| Life quality (QWB) | 0.57±0.06 | 0.58±0.05 | .797 |
| BMI, kg/m2 | 27.04(5.00) | 28.40(3.76) | .280 |
| Quebec Orthopedic Class, n (%) | .628 | ||
| Pain without radiation | 14(58) | 11(42) | |
| Pain and proximal radiation | 3(13) | 4(15) | |
| Pain and distal radiation | 4(17) | 4(15) | |
| Radiation and neurologic signs | 3(13) | 6(23) | |
| Nerve root compression | 0(0) | 1(4) |
Baseline medical and demographic variables were compared using Student t tests and chi-squared tests to determine adequacy of randomization and to examine for differences between participants randomized and analyzed. There were no statistically significant differences between participants randomized to behavioral medicine or attention control conditions in age, education, marital status, ethnicity, annual income, BMI, or orthopedic diagnosis (all P values<.05). Likewise there were no significant differences in baseline pain and disability, the primary outcomes (see table 1).
Preliminary Analyses
Similar rates of dropout were found in each treatment condition (χ2=0.25, df=1, N=67, nonsignificant; see fig 1). There were also no significant baseline differences in demographics or study variables between those who attended less than 4 versus all 4 sessions in either group (all P values>.05). Those who attended all 4 sessions and the 2 boosters were also entirely comparable to those who did not in both groups (all P values>.05). There were also no significant differences between conditions at baseline in demographic or clinical characteristics in either the randomized sample or the sample who attended all 4 therapy sessions and the 6-month follow-up (all P values>.05; see Table 1, Table 2). We concluded there was no systematic bias at baseline between individuals who completed and who did not complete treatment or between treatment conditions.
Next, t tests comparing groups on treatment credibility questions administered in the first session indicated both interventions were equally credible and both clinicians similarly highly regarded (table 3 [means and P values]). Through medical record review and interviews conducted at 6 months, we assessed use of allowed and nonprotocol care in the intent-to-treat sample and completers. There were no differences between treatments in proportion of participants using salicylates or nonsteroidal anti-inflammatory drugs. Muscle relaxants, benzodiazepines, and narcotic analgesics were not prescribed, in line with existing guidelines, and no use was reported. No use of supplemental treatment (eg, chiropractor, acupuncture) was reported. Results were not confounded by group differences in medications or treatments.
Table 3. Comparison of Behavioral Medicine and Attention Control Conditions on Credibility Ratings and Pain Beliefs
| Variable | Behavioral Medicine n=34 | Attention Control n=33 | P Value |
|---|---|---|---|
| Credibility questionnaire | |||
| Treatment believability | 4.58±1.06 | 4.18±1.16 | .155 |
| Probable effectiveness | 4.58±1.03 | 4.33±1.05 | .348 |
| Confidence in treatment | 4.70±1.19 | 4.48±1.03 | .441 |
| Willingness to participate | 5.58±0.71 | 5.58±0.75 | .640 |
| Willingness to recommend | 4.73±1.13 | 4.52±1.15 | .451 |
| Confidence in therapist | 3.91±1.53 | 3.73±1.38 | .613 |
| PAIRS | |||
| Baseline | 65.03±14.49 | 66.70±12.58 | .617 |
| Follow-up⁎ | 50.00±16.20 | 60.60±12.50 | .005 |
⁎N=65. |
Primary and Supplemental Analyses
Independent sample t tests evaluating the secondary outcome of pain beliefs demonstrated no significant differences between behavioral medicine participants and attention controls on baseline PAIRS scores; however, at the 6-month follow-up, as anticipated, treatment participants had significantly lower scores than attention controls (see table 3), indicating less belief that impairment is a necessary consequence of pain. These analyses supported targeted change in pain beliefs in the behavioral medicine intervention relative to attention controls, and served as a manipulation check of the intended treatment.
Primary analyses focused on the proportion of participants recovered at 6 months after pain onset, the widely used cutoff for chronicity. In the modified intent-to-treat sample (N=65), the proportion recovered at 6 months was greater for behavioral medicine (52%) than attention control (31%; χ2=2.75, df=1, P=.09). For those completing 4 sessions (N=50), the proportion recovered at 6 months was more than twice as high in behavioral medicine (54%) as in attention control (23%; χ2=5.12, df=1, P=.02). Recovery rates in the maximum dose sample (N=32) were more than 3 times as high for behavioral medicine (n=12, 75% recovered) as for attention control (n=20, 20%; χ2=9.41, df=1, P=.002).
Comparisons in the modified intent-to-treat sample (table 4) indicated DDS pain intensity (P<.001), disability (P<.001), health status (P<.0001), and functional work category (χ2=5.70, df=2, P=.05) were lower for participants classified as recovered (n=27) versus chronic pain (n=38) at 6 months (see table 4). Exploratory analyses with 80% of participants (n=24 recovered and n=28 chronic pain) who completed 12-month data indicated 79% of recovered versus 68% of chronic pain participants still met criteria for their respective groups (χ2=11.5, df=1, P<.0001). Those recovered at 6 months were, relative to their chronic pain counterparts, more likely to be working productively at 12 months (96% full duty, 4% light duty vs 61% full duty, 18% light duty, 21% medical discharge, respectively; χ2=8.5, df=2, P=.03). These analyses supported the validity of the recovered versus chronic pain outcome distinction.
Table 4. Means and Comparisons of 6-Month Recovered and Chronic Pain Participants on Pain, Disability, Health Status, and Functional Work Category
| Variable | Recovered n=27 | Chronic Pain n=38 | P Value |
|---|---|---|---|
| DDS pain intensity | 1.8±2.3 | 10.1±3.6 | .001 |
| SIP disability | 0.8±0.9 | 10.3±5.8 | .001 |
| VAS current pain | 3.3±6.2 | 32.1±19.6 | .0001 |
| VAS typical pain | 5.5±8.2 | 33.0±19.9 | .0001 |
| QWB health status | 0.8±0.1 | 0.6±0.1 | .0001 |
| Functional work category (%) | .05 | ||
| Full duty | 85 | 58 | |
| Light duty | 15 | 49 | |
| Medical discharge | 0 | 3 |
Discussion
The results suggest early intervention using a behavioral medicine rehabilitation approach may be a useful adjunct to usual medical care to reduce back pain chronicity in patients with first-onset, subacute LBP. Behavioral medicine participants, compared with attention controls, were more likely to experience enhanced function and pain resolution at the 6-month follow-up. Recovery rates, defined in terms of both pain and function, were about 15% more favorable for behavioral medicine relative to attention control among randomized participants, 2 times better for those completing a full dose of treatment, and more than 3 times better for those who also attended the booster sessions and received the maximum therapeutic dose. The timing and nature of this intervention was in accord with current clinical guidelines,15 which recommend cognitive-behavioral approaches for patients with chronic or subacute LBP who do not improve with self-care education.
The design and analyses allowed us to address several competing explanations for results. We did not find any evidence of systematic bias in group composition, attendance, or completion patterns. Both interventions were similarly credible, and patients had equivalent confidence in the therapists. We took steps to mask study conditions and hypotheses from therapists, assessors, and participants, although we did not verify the success of the therapist blind. Anecdotal evidence from session reviews and therapist debriefing suggests that the blind held. The intervention worked as intended in that behavioral medicine participants decreased more than twice as much as attention controls on attitudes that equate pain with disability; however, a limitation is that we did not directly assess acquisition of behavioral skills.
We acknowledge some additional limitations in this exploratory study. The study sample was small and limited mostly to men attending a closed medical care system. Participant withdrawal prior to randomization, although in line with other such studies (eg, see reference16), was higher than desired. The higher rate of attendance among attention controls might be attributable to therapist effects, but also might indicate a need for modifications to make behavioral medicine interventions more palatable or accessible to patients in health care settings. Because each therapist delivered either behavioral medicine or attention control, but not both, therapist and condition may have been confounded. Both therapists were similarly trained and experienced clinicians, and treatment was standardized and closely supervised, which offsets this risk to some extent. Crossover of therapists was not used because of increased risk of expectancy biases. Results from the secondary analyses should be interpreted with caution because of a possibly increased risk of type I error. Finally, the attention control condition may have reduced fear of activity or enhanced self-efficacy by virtue of therapist encouragement and empathy. If such effects existed, they did not appear to provide the same functional benefits as a more directive treatment aimed at rehabilitation.
The chronicity endpoint of 6 months after pain onset might be criticized for leading to a variable length of time between baseline and follow-up assessments. On the other hand, this study sought to prevent chronicity, defined by a well accepted convention as 6 months of daily pain.25 We defined recovery based on established methods for defining significant clinical change. Although this approach may be criticized as restrictive, it employs an empirical approach, rather than an arbitrary one, to define chronicity, and is rigorous and conservative.
These results add to other evidence suggesting early intervention designed to foster activity and restore functioning may be helpful in reducing later disability. We speculate the therapeutic ingredients of behavioral medicine to be developing an organized plan of action, offering methods to analyze and overcome obstacles, setting goals, providing feedback, and teaching a cognitive-behavioral conceptualization of back pain (eg, see references16, 17, 25, 32, 33, 56). These techniques should produce attitudes and behaviors consistent with pain self-management, although only attitude change was verified in this study.
Recovery rates in this study were higher than those found in an earlier observational study that used identical inclusion criteria and measures and similar methods for defining recovery.10 The recovery rate at 6 months in that study was 32%, which is strikingly similar to the present study's 31% recovery rate in attention controls, but substantially less than the 52% rate observed with behavioral medicine in the intent-to-treat sample (χ2=4.18, P<.05). Among behavioral medicine participants who completed the maximum treatment dose, the recovery rate was 75%. While nonrandomized comparisons must be interpreted cautiously, these data indicate a possible dose-response effect. The relatively large effects observed, combined with results from other studies,16, 17, 18, 19 suggest that early intervention with a behavioral medicine rehabilitation approach may have potential as a treatment strategy for reducing LBP chronicity and disability, and is worthy of additional study.
The stepped care model for back pain management suggests all patients might benefit from information and encouragement, whereas progressively more intensive therapy is needed for patients with activity limitations, with the highest level of care reserved for those with difficulty in work-role function.57 This study demonstrates that behavioral medicine rehabilitation techniques applied at the subacute phase can significantly enhance recovery and prevent chronicity in the latter, most severe group. The structured nature of behavioral medicine means that clinic staff with a variety of specialties can be trained in these methods. As such, behavioral medicine techniques might easily be integrated into a coordinated active management approach,58 in which different health care professionals provide similar information and advice to enhance recovery.
Conclusions
A behavioral medicine, rehabilitation intervention applied at the subacute phase for individuals with first-onset LBP and moderate functional work limitations enhanced recovery and reduced chronic pain and disability at 6 months after pain onset, relative to an attention control condition. This pilot study supports the initial feasibility and potential utility of early behavioral intervention for subacute LBP.
Acknowledgments
The authors acknowledge the valuable assistance of Patricia Bone, RN, Nann Epler, BA, Lauren Gosewisch, RN, Judy Ortega, BA, and Jane Corzine, BA, in conducting this research.
References
- . The most expensive medical conditions in America. Health Aff (Millwood). 2002;21:105–111
- . Estimates and patterns of direct health care expenditures among individuals with back pain in the United States. Spine. 2004;29:79–86
- . Back pain prevalence and visit rates: estimates from U.S. national surveys, 2002. Spine. 2006;31:2724–2727
- . Physician office visits for low back pain: frequency, clinical evaluation, and treatment patterns from a U.S. national survey. Spine. 1995;20:11–19
- Acute low back pain: systematic review of its prognosis. BMJ. 2003;327:323
- Length of disability and cost of workers' compensation low back pain claims. J Occup Environ Med. 1997;39:937–945
- . Do epidemiological results replicate? (the prevalence and health-economic consequences of neck and back pain in the general population). Eur J Pain. 2000;4:347–354
- . Medical management of acute and chronic low back pain: an evidence-based approach. Amsterdam: Elsevier; 2002;
- Disability resulting from occupational low back pain, part II: what do we know about secondary prevention? a review of the scientific evidence on prevention after disability begins. Spine. 1996;21:2918–2929
- One-year follow-up of first onset low back pain. Pain. 1997;73:213–221
- . Psychosocial predictors of outcome in acute and subchronic low back trouble. Spine. 1995;20:722–728
- . Fear avoidance and prognosis in back pain: a systematic review and synthesis of current evidence. Arthritis Rheum. 2006;54:3999–4010
- . Do psychological factors predict outcome in both low-back pain and shoulder pain?. Ann Rheum Dis. 2007;66:313–319
- . A review of psychological risk factors in back and neck pain. Spine. 2000;25:1148–1156
- . Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Ann Intern Med. 2007;147:478–491
- . Can chronic disability be prevented? (a randomized trial of a cognitive-behavior intervention and two forms of information for patients with spinal pain). Spine. 2000;25:2825–2831discussion 2824
- . A 5-year follow-up evaluation of the health and economic consequences of an early cognitive behavioral intervention for back pain: a randomized, controlled trial. Spine. 2006;31:853–858
- A randomized trial of a cognitive-behavioral program for enhancing back pain self care in a primary care setting. Pain. 2000;88:145–153
- A randomized trial of a lay person-led self-management group intervention for back pain patients in primary care. Spine. 1998;23:2608–2615
- . The back pain revolution. 2nd ed.. New York: Churchill Livingstone; 1996;
- . Intensive group training versus cognitive intervention in sub-acute low back pain: short-term results of a single-blind randomized controlled trial. J Rehabil Med. 2003;35:132–140
- Coordination of primary health care for back pain: a randomized controlled trial. Spine. 2000;25:251–258discussion 258
- . Good prognosis for low back pain when left untampered: a randomized clinical trial. Spine. 1995;20:473–477
- . Five-year follow-up study of a controlled clinical trial using light mobilization and an informative approach to low back pain. Spine. 1998;23:2625–2630
- . Behavioral methods in chronic pain and illness. St Louis: CV Mosby; 1976;
- . The importance of placebo effects in pain treatment and research. JAMA. 1994;271:1609–1614
- An empirical evaluation of multidimensional clinical outcome in chronic low back pain patients. Pain. 1993;55:107–118
- Psychosocial factors discriminate multidimensional clinical groups of chronic low back pain patients. Pain. 1995;62:349–355
- . Clinical significance: a statistical approach to defining meaningful change in psychotherapy research. J Consult Clin Psychol. 1991;59:12–19
- Acute low back problems in adults. Clinical practice guideline no. 14. AHCPR publication no. 95-0642. Rockville: Agency for Health Care Policy and Research, Public Health Service, US Department of Health and Human Services; December 1994;
- . Good news for bad backs. Readers Digest. 1995;146:119–123
- . Behavioral medicine approaches to chronic pain. In: Herkowitz H, Garfin S, Bladerston RF, Eismont FG, Bell G, Weisel S editor. 3rd ed.. Rothman and Simeone's the spine. Vol 2:Philadelphia: Saunders; 1992;p. 1961–1982
- . Behavioral management of chronic pain. Holist Nurs Pract. 1991;6:66–75
- . The clinical significance of behavioral treatment for chronic low back pain: an evaluation of effectiveness. Pain. 1997;71:257–263
- . The control group dilemma in clinical research: applications for psychosocial and behavioral medicine trials. Psychosom Med. 1997;59:362–371
- . Person to person: the problem of being human; a new trend in psychology. Walnut Creek: Real People Press; 1967;
- . Evidence for success of behavior modification in weight loss and control. Ann Intern Med. 1993;119:698–701
- . The Descriptor Differential Scale: applying psychophysical principles to clinical pain assessment. Pain. 1988;35:279–288
- . The Descriptor Differential Scale of Pain Intensity: an evaluation of item and scale properties. Pain. 1995;61:251–260
- The sickness impact profile: development of an outcome measure of health care. Am J Public Health. 1975;65:1304–1310
- . Measuring physical and psychosocial function in patients with low-back pain. Spine. 1983;8:635–642
- . Validity of the Sickness Impact Profile Roland scale as a measure of dysfunction in chronic pain patients. Pain. 1992;50:157–162
- . Effectiveness of behavioral therapy for chronic low back pain: a component analysis. J Consult Clin Psychol. 1990;58:573–579
- . Comparison of group progressive-relaxation training and cognitive-behavioral group therapy for chronic low back pain. J Consult Clin Psychol. 1982;50:757–765
- . The sickness impact profile: a global measure of disability in chronic low back pain. Pain. 1985;21:67–76
- . Health status: types of validity and the index of well-being. Health Serv Res. 1976;11:478–507
- . Health-related quality of life measurement for evaluation research and policy analysis. Health Psychol. 1982;1:61–80
- . A general health policy model: update and applications. Health Serv Res. 1988;23:203–235
- A placebo-controlled randomized clinical trial of nortriptyline for chronic low back pain. Pain. 1998;76:287–296
- . Chronic pain and functional impairment: assessing beliefs about their relationship. Arch Phys Med Rehabil. 1988;69:579–582
- . Pain and impairment beliefs in chronic low back pain: validation of the Pain and Impairment Relationship Scale (PAIRS). Pain. 1991;44:51–56
- . Scientific approach to the assessment and management of activity-related spinal disorders (A monograph for clinicians). Report of the Quebec Task Force on Spinal Disorders (Spine). 1987;12(Suppl):S1–S59
- . Definition, measurement, and classification of the syndromes of obesity. Int J Obes. 1978;2:99–112
- . Risk factors for low back pain and sciatica. Ann Med. 1989;21:257–264
- . Credibility of analogue therapy rationales. J Behav Ther Exp Psychiatry. 1972;3:257–260
- . Pain and behavioral medicine: a cognitive-behavioral perspective. New York: Guilford Pr; 1983;
- . Pain management in primary care: an individualized stepped care approach. In: Gatchel R, Turk D editor. Psychosocial factors in pain: evolution and revolutions. New York: Guilford Pr; 1999;
- . Information and advice to patients with back pain can have a positive effect: a randomized controlled trial of a novel educational booklet in primary care. Spine. 1999;24:2484–2491
Supported by the Office of Research and Development, Health Services Research and Development Service and Medical Research Service, Department of Veterans Affairs (grant no. IIR-94-028).
The opinions expressed are those of the authors and do not reflect the official policy or position of the Department of the Navy, the Department of Defense, or the United States Government. The voluntary informed consent of the subjects used in this research was obtained as required by SECNAVINST 3900.39B. The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC, Clinical Investigation Program, sponsored this report, as required by HSETCINST 6000.41A.
A commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a financial benefit on 1 of the authors. Dr Atkinson is on the Scientific Advisory Board of Eli Lilly, which sells antidepressants, an alternative treatment method for low back pain.
Reprints are not available from the author.
PII: S0003-9993(09)00082-3
doi:10.1016/j.apmr.2008.10.032
Published by Elsevier Inc.
Volume 90, Issue 4 , Pages 545-552, April 2009
