Yoga, Physical Therapy, or Education for Chronic Low Back Pain

Low back pain is the leading cause of disability globally (1). Total annual back painrelated costs in the United States exceed $200 billion (2). Chronic low back pain (cLBP) affects approximately 10% of U.S. adults (3), but overall patient satisfaction with cLBP treatment is low (4). The impact of cLBP is greater in racial or ethnic minorities and in people of lower socioeconomic status (SES) (5). Physical therapy (PT), comprising individually tailored stretching and strengthening exercises, is the most common evidence-based, reimbursable, and nonpharmacologic physician referral for cLBP (6, 7). Clinical guidelines (8, 9), meta-analyses (10), and several large randomized controlled trials (1113) also support yoga, a practice including physical poses, breathing exercises, and meditation, as an effective cLBP treatment. To improve cLBP care, physicians, patients, and payers need to know how novel therapies like yoga compare with established treatments like PT. Noninferiority trials determine whether a new therapy is statistically as effective as an accepted treatment (14). This is particularly useful when the new therapy may have other potential benefits, such as lower cost. The U.S. Food and Drug Administration uses noninferiority as one criterion for approving new pharmaceuticals (15). Although no criteria have been established for when a new nonpharmacologic therapy should be integrated into mainstream clinical practice, demonstrating noninferiority to effective, reimbursed, and nonpharmacologic treatments is one reasonable requirement. Thus, we conducted a randomized controlled comparative effectiveness trial testing whether yoga was noninferior to PT in adults with cLBP. Methods Design Overview The study protocol (16) and treatment manuals (1720) were published previously. We conducted a 52-week, assessor-blinded randomized trial of yoga, PT, and education (a self-care book and newsletters) for adults with nonspecific cLBP. The study was advertised as a comparison of 3 credible cLBP treatments. All participants had access to usual medical care. The study consisted of a 12-week treatment phase and 40-week maintenance phase. The primary hypothesis was that yoga is noninferior to PT in the treatment phase for improving both back-related function and pain intensity. The secondary hypothesis was that both yoga and PT are superior to education for improving function and pain. The maintenance phase compared the effectiveness of different strategies for ongoing yoga and PT. Yoga participants who completed 1 or more yoga classes in the treatment phase were randomly assigned at 12 weeks to yoga drop-in classes or home practice. Physical therapy patients who completed 1 or more PT appointments in the treatment phase were randomly assigned to PT booster sessions or home practice. We hypothesized that at 52 weeks, yoga drop-in classes are superior to yoga home practice and PT booster sessions are superior to PT home practice. Participants were recruited from June 2012 to November 2013. Follow-up was completed in November 2014. The original research protocol and a summary of protocol changes are in Supplement 1. Supplement 1. Detailed Study Protocol Setting and Participants The study was done at a large academic safety-net hospital and 7 affiliated, federally qualified community health centers located in diverse neighborhoods. Staff doing data collection, entry, and analysis were masked to treatment assignment. The Boston University Institutional Review Board approved the study before data collection. We enrolled English-speaking adults aged 18 to 64 years who reported nonspecific low back pain lasting at least 12 weeks with an average pain intensity in the previous week of 4 or greater on an 11-point (0 to 10) numerical rating scale. Persons with specific causes of cLBP (for example, spinal stenosis) were excluded. Eligibility criteria are in Table 1 of Supplement 2. Recruitment strategies included clinician referrals, mailing letters to patients with cLBP who were identified through electronic health records, and distributing flyers in clinics and surrounding neighborhoods. Supplement 2. Data Supplement Randomization and Interventions After initial telephone screening, staff confirmed eligibility and obtained written informed consent during in-person meetings. Staff entered participants into StudyTRAX (ScienceTrax), a data management platform. StudyTRAX generated a randomization sequence using permuted block randomization with varying block sizes and a 2:2:1 ratio of yoga, PT, and education. After participants completed baseline surveys, unmasked staff informed them of their treatment assignments. Enrollment and randomization proceeded in 4 sequential cohorts of approximately 80 participants each. Yoga participants who attended at least 1 class in the treatment phase continued into the maintenance phase and were randomly assigned to weekly drop-in yoga classes or home practice only. Physical therapy participants with at least 1 PT visit in the treatment phase were randomly assigned to attend 5 booster sessions or home practice only during the maintenance phase. Education participants continued into the maintenance phase without additional randomization. A manualized yoga protocol (18) of 12 weekly 75-minute classes was adapted from previous studies in similar populations (21, 22) with input from expert yoga instructors, investigators, and former study participants (Table 2 of Supplement 2). Thirteen yoga instructors completed 8 hours of training and taught classes at 6 sites. Instructor assignments ensured a participantinstructor ratio of less than 5:1. Each class began with relaxation and meditation exercises, yoga breathing, and yoga philosophy. It continued with yoga poses and concluded with relaxation. Pose variations and aids (such as chair, strap, and blocks) accommodated various abilities. Thirty minutes of daily home practice, facilitated by a DVD, a manual, and take-home yoga supplies, was strongly encouraged. Participants recorded time spent practicing. Staff observed approximately 10% of classes to assess protocol fidelity by using a checklist. Maintenance phase classes were similarly structured except for a higher participantinstructor ratio (approximately 8:1). The manualized PT protocol (Figure 1 and Table 3 of Supplement 2) incorporated treatment-based classification (23, 24), graded exercise (25), and screening for fear-avoidance beliefs (26). Eight physical therapists delivered the intervention in 1 hospital-based and 2 community-based PT clinics. Physical therapists completed 8 hours of in-person training and Web-based modules (27). Participants were advised to attend fifteen 60-minute appointments over 12 weeks. Appointments included one-on-one work with the therapist and supervised aerobic exercise. All participants completed the Fear-Avoidance Beliefs Questionnaire (28). For PT participants with a high fear-avoidance score (29 on the work subscale), therapists provided The Back Book (29) and reinforced its psychologically informed principles to lower fear avoidance. Participants received written instructions and supplies for home practice and logged the number of exercises completed daily. Staff assessed protocol fidelity by reviewing therapists' treatment flowsheets. Participants randomly assigned to booster sessions during the maintenance phase were advised to see the therapist at 4, 6, 8, 10, and 12 months. Education participants received The Back Pain Helpbook (30), which includes information on cLBP self-management, stretching, strengthening, and the role of emotions and fear avoidance. Previous cLBP trials (11, 12, 31) used this book as a credible control intervention. We provided a recommended reading schedule (Table 4 of Supplement 2). Every 3 weeks, participants received a 1- to 2-page newsletter (32), summarizing main points from assigned chapters, and a 5- to 10-minute check-in call from staff. In the maintenance phase, we made brief check-in calls every 6 weeks to encourage continued review of the book. Outcomes and Follow-up Coprimary outcomes were change from baseline to 12 weeks in scores on the modified Roland Morris Disability Questionnaire (RMDQ), a 23-point measure of back-related function with higher scores indicating worse function (33), and in pain (using an 11-point numerical rating scale for average intensity in the previous week, where 0 indicated no pain and 10 indicated worst pain possible) (34). Secondary outcomes included self-reported pain medication use in the previous week (yes or no), global improvement (7-point scale from extremely worsened to extremely improved), patient satisfaction with interventions (5-point scale from very dissatisfied to very satisfied) (35), and health-related quality of life (Short Form-36 Health Survey) (36). We collected data on work productivity, a secondary outcome, and will report them separately in a cost-effectiveness analysis. We also plan to report data on other exploratory measures collected (such as fear-avoidance beliefs, pain self-efficacy, depression, anxiety, and sleep) separately. Attendance at all yoga and PT sessions was recorded. Participants attending at least 9 yoga or 11 PT sessions (75% or 73% of sessions, respectively) were defined as adherent a priori. Education participants were asked how much of the book they had read. Those reporting having read at least 75% were defined as adherent a priori. After baseline data collection, study staff that was blinded to treatment assignment collected paper surveys completed at 6, 12, 26, 40, and 52 weeks. Adverse events were elicited directly from participants and in surveys. Participants received $100 gift cards after completing surveys at 12 and 52 weeks and $50 gift cards after the baseline questionnaire and surveys at 6, 26, and 40 weeks. Statistical Analysis The study was designed and powered to detect if yoga was noninferior to PT at 12 weeks for both primary outcomes. N