Abstract
Objective. To evaluate the effect of Integral-based hatha yoga in sedentary people with arthritis.
Methods. There were 75 sedentary adults aged 18+ years with rheumatoid arthritis (RA) or knee osteoarthritis randomly assigned to 8 weeks of yoga (two 60-min classes and 1 home practice/wk) or waitlist. Poses were modified for individual needs. The primary endpoint was physical health [Medical Outcomes Study Short Form-36 (SF-36) physical component summary (PCS)] adjusted for baseline; exploratory adjusted outcomes included fitness, mood, stress, self-efficacy, SF-36 health-related quality of life (HRQOL), and RA disease activity. In everyone completing yoga, we explored longterm effects at 9 months.
Results. Participants were mostly female (96%), white (55%), and college-educated (51%), with a mean (SD) age of 52 years (12 yrs). Average disease duration was 9 years and 49% had RA. At 8 weeks, yoga was associated with significantly higher PCS (6.5, 95% CI 2.0–10.7), walking capacity (125 m, 95% CI 15–235), positive affect (5.2, 95% CI 1.4–8.9), and lower Center for Epidemiologic Studies Depression Scale (−3.0, 95% CI −4.8 – −1.3). Significant improvements (p < 0.05) were evident in SF-36 role physical, pain, general health, vitality, and mental health scales. Balance, grip strength, and flexibility were similar between groups. Twenty-two out of 28 in the waitlist group completed yoga. Among all yoga participants, significant (p < 0.05) improvements were observed in mean PCS, flexibility, 6-min walk, and all psychological and most HRQOL domains at 8 weeks with most still evident 9 months later. Of 7 adverse events, none were associated with yoga.
Conclusion. Preliminary evidence suggests yoga may help sedentary individuals with arthritis safely increase physical activity, and improve physical and psychological health and HRQOL. Clinical Trials NCT00349869.
For people with arthritis, physical activity is essential for optimal disease management and preserving mobility1,2. Exercise helps maintain range of motion, joint stability, and muscle mass, while reducing pain and fatigue3,4,5. The stress reduction associated with exercise can help individuals adaptively cope to living with a painful, chronic illness, and emerging evidence also suggests beneficial effects on systemic inflammation and immune function6,7. However, despite the well-known benefits of physical activity, up to 44% of people with arthritis report no leisure time physical activity8 and 76% are inadequately active9. Indeed, arthritis appears to be a major barrier to physical activity; among people with heart disease, those with arthritis were 60% more likely to be inactive10.
Yoga may be well-suited for arthritis by combining physical activity with potent stress management techniques, including breathing, relaxation, and mindfulness11. In 2012, 20 million US adults (nearly 1 in 10) practiced yoga to improve health and fitness, with 40% starting in the past year alone12. The 2007 National Health Interview Survey listed yoga as the sixth most commonly used complementary health practice among adults13. In both healthy and clinical populations, the health benefits of yoga appear to be similar to other forms of exercise14,15,16. The strongest evidence of benefit is for reducing pain [standardized mean difference (SMD) −0.74, 95% CI −0.97 – −0.52], pain-related disability (SMD −0.79, 95% CI −1.02 – −0.56)17, and improving mood (SMD −0.65, 95% CI −0.89 – −0.42)18. However, medical professionals may be concerned that yoga’s emphasis on changing positions and flexibility could stress vulnerable joints affected by arthritis.
Unfortunately, the evidence base is limited regarding yoga in arthritis. We summarized 10 peer-reviewed articles and abstracts of yoga and arthritis through 201019; the existing studies, conducted in diverse populations around the world, were mostly of low quality (small samples, nonrandomized trials, heterogeneity of dose, methods, and outcomes) and precluded drawing conclusions. Other reviews of recent trials in rheumatic conditions have noted ongoing concerns with study quality, but the emerging evidence does suggest that yoga may improve arthritis symptoms (pain, stiffness, tenderness), function, and mood19,20,21,22. Given its popularity and availability, well-controlled trials are needed to guide recommendations about yoga in arthritis15,20,21,22.
Hence, our goal was to contribute evidence about outcomes associated with initiating yoga practice in sedentary people with arthritis. An 8-week program was developed, emphasizing individualized adaptations and monitoring, to promote successful transition to home practice. We hypothesized that yoga would improve physical health, fitness, psychological function, health-related quality of life (HRQOL), and arthritis self-efficacy with no worsening of rheumatoid arthritis (RA) disease activity.
MATERIALS AND METHODS
Study design
A parallel-arms pragmatic 8-week randomized controlled trial (RCT) compared Integral-based hatha yoga and waitlist groups. Pragmatic RCT use rigorous methodology (randomization, blinding, allocation concealment) to reduce bias, but allow flexibility in intervention delivery and enhance external validity by testing existing programs in real-world settings and with less stringent inclusion criteria23. Individuals were randomly assigned 1:1 to yoga or waitlist. This study was approved by the Johns Hopkins Institutional Review Board and registered with clinicaltrials.gov (NCT00349869).
The study was originally for RA; after 31 patients were enrolled, additional funding was secured and the study was expanded to include knee osteoarthritis (OA). Although these diseases have different underlying mechanisms, both result in significant joint pain and disability, and community classes are likely to include people with both conditions. Additional secondary endpoints were added.
We also explored the effects of yoga over time. After completing 8-week followup assessments, waitlisted participants were invited to join upcoming classes. We also completed followup assessments of these participants after 8 weeks of yoga, and of everyone who had completed yoga 9 months after classes had ended.
Participants
Eligibility criteria included (1) patients with RA, age 18–70 years; and patients with OA, 18+; (2) sedentary (physically active for 20 min < 3 times/week); and (3) diagnosed with RA, OA, or probable knee OA as indicated by a positive response to questions used in trials to identify knee OA24. Exclusion criteria were (1) use of cane, walker, or wheelchair; (2) other inflammatory conditions; or (3) surgery within 6 months. For RA, medical clearance was required. Eligibility criteria were deliberately broad to ensure participants reflected typical people with arthritis living in the community. Enrollment occurred from June 2005 through July 2008, and ended when 75 participants had been enrolled.
Recruitment and allocation
Participants were recruited from arthritis clinics, private practices, and using local flyers. The Maryland Arthritis Foundation Chapter also publicized the study in newsletters. Potential participants were screened by phone and eligible persons provided written consent and underwent baseline assessments. Rheumatologists and all assessors remained blinded to treatment assignment.
Simple random assignment was done by a third party using a Web-based randomizer; allocation sequence was concealed from all study team members by using sequentially numbered, sealed opaque envelopes that were opened by the coordinator once baseline assessments were completed. Yoga classes began once 12–15 people were available (i.e., had been randomized after baseline and/or completed waitlist).
Treatment arms
Yoga consisted of 60-min classes held twice weekly for 8 weeks at 2 hospital-affiliated fitness centers in Baltimore, Maryland, USA. The program was designed by a registered yoga therapist (SM) with input from the Johns Hopkins Arthritis Center faculty. Two yoga therapists with 10+ years of experience taught the classes. Yoga therapists have additional training to address the needs of people with diverse conditions/abilities.
Each class began with questions/comments (5 min), breathing exercises and chanting (5 min), warm-up and moving sequence (surya namaskara, 15 min), and isometric poses (asanas, 20 min) to increase strength, flexibility, and balance. Classes ended with deep relaxation (sivasana, 10 min), a closing chant, and meditation (5 min). See Appendices for sample class and modifications. Poses included gentle forward bends, backbends, twists, balances, standing, sitting, and lying poses, and were modified for individuals at the discretion of the teacher and/or participant. Complexity of poses and intensity was standardized to allow gradual progression. Eight weeks was selected for the intervention because this provides sufficient time to introduce independent practice and is a common duration of introductory classes. Props included blocks, straps, blankets, and chairs. Participants were encouraged to try new skills, but to remain safe and avoid discomfort. Written instructions with pictures for home practice and selected readings describing potential benefits of yoga components (breathing, meditation, mindfulness) were provided weekly. Home practice evolved gradually to develop the skills and confidence for longterm adherence. Participants were asked to keep arthritis medications constant and were queried regularly by coordinators about any changes.
The waitlist group received usual care for 8 weeks. They were asked to maintain current levels of physical activity and inform coordinators of changes in health or arthritis medications. After Week 8 assessments, they were invited to participate in upcoming classes.
Dependent measures
Measures were obtained by blinded assessors at baseline, Week 8, and 9 months (yoga only) at the Johns Hopkins Bayview General Clinical Research Center.
The primary endpoint was the Medical Outcomes Study Short Form-36 (SF-36) physical component summary (PCS) at Week 8. The SF-36 assesses 8 domains with higher scores representing better HRQOL. The PCS and mental component scores (MCS) differentially weight all scales using a t-score metric (mean 50 and SD 10). The PCS, which emphasizes physical function, fulfilling physical roles and bodily pain, is reliable (ICC 0.81) and responsive to change (SRM 0.61)25,26.
Exploratory endpoints included fitness, psychological function, and HRQOL. Using standardized protocols, flexibility was measured using a sit-and-reach box27, balance with 1-leg stance (OLS; maximum 30 s), and strength with a hand dynamometer28. For each measure, the best of 3 attempts was recorded. The 6-min walk29 measured walking capacity.
The SF-36 MCS provided an overall index of mental health. Depressive symptoms were assessed using the 11-item Center for Epidemiologic Studies–Depression Scale (CES-D)30 that has a similar factor structure and properties as the original scale and is validated in arthritis31. The Positive and Negative Affect Scale (PANAS) assessed mood. The PANAS is reliable (r = 0.86 and 0.87 for PA and NA) and internally consistent (α = 0.86–0.90 for PA and 0.84–0.87 for NA)32. Stress was measured with the Perceived Stress Scale, which is reliable (r = 0.84–0.86) and correlates moderately with number and effect of life events (r = 0.33–0.49)33. The Arthritis Self-efficacy Scale, which measures confidence to manage arthritis, is internally consistent (r = 0.94) and reliable (r > 0.85)34. For RA, 28 tender and swollen joint counts were conducted by trained assessors, and participants completed the 100 mm patient’s global assessment (PtGA) visual analog scale. Attendance was recorded at classes.
Statistical analysis
Our study was designed and powered to detect an 8-point difference in PCS between groups. (The minimal clinically important difference for RA is 5.) A sample size of 30/group was sufficient to detect this difference, assuming an SD of 11 points, power of 80%, and significance of 5%.
Groups were compared on sociodemographic and SF-36 scores by arthritis type using Student t tests and chi-square tests. To assess the effect of missing data for variables added after the study began, we compared characteristics of the first 31 participants with the last 44, and also used multiple imputation and last observation carried forward (LOCF).
The primary RCT analysis was ANCOVA by group with adjustment for baseline values (Model 1). In Model 2, we also added adjustment for age. Baseline covariates were chosen to improve the precision of estimates; age was explored given its associations with outcomes and because of chance imbalances between groups despite randomization35 after first testing for homogeneity of regression slopes by treatment. Paired Student t tests also explored within-group differences after 8 weeks of yoga and 9 months later.
RCT data were analyzed based on treatment assignment. Because this was an exploratory study, we did not control for multiple comparisons. All analyses were performed using IBM SPSS, version 21.
RESULTS
Of 103 people who contacted the research team, 19 were ineligible because of current physical activity (11), recent/planned surgery (5), and use of assistive devices (3); 9 declined because of time requirements (Figure 1). Thus, 75 participants were randomly assigned to yoga (n = 40) or waitlist (n = 35). Participants were mostly middle-aged (mean ± SD, 52 ± 12 yrs), female (96%), and white (55%), with 39% black. About half (51%) were college-educated and 49% had RA with an average duration of 9 ± 9 years.
Flow of yoga and usual care participants throughout an 8-week randomized controlled trial and 9-month followup (yoga participants only).
Of the last 44 enrolled, 67% had OA; the mean age of those enrolled when recruitment was expanded was significantly higher than the original cohort, but did not differ on other sociodemographic or arthritis variables (data not shown). Yoga participants were significantly younger than waitlist, but did not otherwise differ (Table 1). Participants with RA were significantly younger and had significantly lower SF-36 MCS, general health, social function, and mental health scores (Table 2).
Baseline characteristics of participants. Values are mean ± SD or % unless otherwise specified.
Participant characteristics by arthritis type. Values are the mean ± SD or n (%) unless otherwise indicated.
Among 40 yoga participants, 7 withdrew (see Figure 1 for reasons) between baseline and the start of classes, and 8 withdrew during the intervention. Thus, Week 8 data were available for 25 participants. Most who completed yoga (22, 79%) attended at least 12/16 classes. Of 35 people in the waitlist group, 7 withdrew; Week 8 data were available for 28 people. Study completers did not differ significantly from withdrawals by age, sex, education, diagnosis, disease duration, pain, or physical function, but were more likely to be minorities (OR 4.3, 95% CI 1.5–12.4). The most common reasons for withdrawal were life events and scheduling.
Physical health and fitness
At Week 8, in adjusted analyses (Model 1), the mean PCS score for yoga was 6.5 points higher than waitlist (p < 0.001; Table 3); this 0.7 SD difference is both statistically and clinically meaningful and persisted with adjustment for age (Model 2). Walking capacity was also significantly higher for yoga (125 m); there was a trend (p = 0.056) for sit-and-reach scores to also being higher. OLS and grip strength did not differ between groups. In Model 2, with additional adjustment for age, differences in flexibility reached statistical significance; however, 6-min walk, grip strength, and balance were not significantly different between groups. Results were similar using LOCF (data not shown).
Physical health, fitness, psychological function, and HRQOL by group at baseline and Week 8 of RCT. Values are the mean ± SD unless otherwise specified.
Psychological function
At Week 8, with adjustment for baseline, the yoga group reported significantly fewer depressive symptoms (CES-D) and higher positive affect (PANAS). However, groups did not differ on SF-36 MCS, negative affect, perceived stress, or arthritis self-efficacy. Results were unchanged with adjustment for age.
HRQOL
At Week 8, adjusted analyses showed yoga participants reported significantly less impairment on SF-36 role physical, body pain, general health, vitality, and mental health scales, with trends (p < 0.08) evident in physical function and role emotional. Within groups, yoga improved significantly on all SF-36 scales, except role emotional, while scores were essentially unchanged in waitlist. Significant differences were evident in the same SF-36 scales, except general health with further adjustment for age.
In 25 participants with RA, we also explored changes in joint counts and PtGA scores (Table 4). Swollen and tender joint counts decreased and PtGA scores improved in both groups, and were not statistically different in baseline-adjusted analyses between groups at Week 8.
Change in tender and swollen joints and patient’s global assessment (PtGA) scores in RCT participants with RA. Values are the mean ± SD unless otherwise specified.
Yoga group
At Week 8, 22 of 28 waitlist participants (79%) began yoga. Characteristics were similar between waitlist participants who did and did not start yoga (data not shown). Overall, of 55 who began yoga, 44 (80%) completed Week 8 testing. PCS, all fitness (except OLS), psychological, and SF-36 measures (except role emotional) improved significantly (Table 5). Followup data were available on 37 participants (67%) 9 months after completing yoga. Improvements were still evident in PCS, sit-and-reach, 6-min walk, CES-D, positive and negative affects, perceived stress, and SF-36 physical function, role physical, bodily pain, and vitality scales.
Physical health, fitness, psychological function, and HRQOL in all yoga participants at Week 0, Week 8, and 9 months. Values are the mean ± SD unless otherwise specified.
Adverse events
No adverse events were specifically associated with yoga. The 7 events (1 each) reported to the Internal Review Board for the yoga group (not attributed to yoga) included bruising (workplace accident), ovarian cancer recurrence, bladder cancer, tendinitis, hyperthyroidism, allergic reaction, and new RA diagnosis (study end). No adverse events occurred in the waitlist group.
DISCUSSION
To date, this is the largest RCT of OA and RA, and to our knowledge the first to assess physical health and fitness using self-reported and performance measures along with psychological function and HRQOL. This is only the second study in arthritis (of 20 published to date) to include safety data. As compared to waitlist, yoga was associated with substantial improvements in physical and general health perceptions, physical roles, walking, pain, energy, and mood. Regular yoga practice was not associated with worsening joint symptoms or adverse events. Indeed, in RA, swollen and tender joint counts decreased significantly with yoga, though a similar trend was evident in the waitlist.
Although 24% dropped out of yoga, persistence was still higher than in many exercise programs36, with most attending the majority of classes. The most common reason people withdrew was because of time/schedule conflicts. Other studies37,38 have also reported higher rates of adherence to yoga than studies with clinical populations where < 50% continue exercising by 3 months39. Reducing inactivity is an important public health challenge, especially in arthritis, where only 1 in 4 are meeting activity guidelines9. Notably, 80% of the waitlist group opted to take yoga. Assessments 9 months later indicated the durability of most improvements.
At Week 8, the 6.5-point difference between groups in PCS indicated important improvements in health. PCS scores reflect physical function, role physical (work and daily activity impairments because of physical health), pain, and energy. Indeed, in the yoga group, 16/44 (36%) improved 1 category or more on the SF-36 self-rating of health. We noted a trend toward improved physical function with yoga at Week 8, as have others37,40,41,42, though not all43. When we pooled data from all yoga completers, there were significant improvements in all HRQOL scales except role emotional, which was already close to population norms at baseline.
We hypothesized that yoga would lead to improved flexibility, balance, and strength. Flexibility, which has not been previously evaluated in arthritis, improved with practice, although differences were not statistically significant (p = 0.056). Because loss of joint mobility is common in arthritis, preserving range of motion is important for maintaining mobility. However, yoga was not associated with improved balance, in contrast to the findings by others44, perhaps because baseline values were already high. For example, 45% of participants scored at maximum levels (30 s) at baseline; among those with scores < 30 s, 54% improved with yoga. Tai chi also may enhance balance and reduce the risk of falls in arthritis45. Future yoga studies should further evaluate flexibility and balance. We also did not find improvements in grip strength; Garfinkel, et al also found no change in grip strength with yoga in hand OA46, although this has been reported by others in RA47,48. However, grip strength assesses upper limb strength and may not adequately characterize muscle strength of the entire body. Yoga targets many muscle groups, and many poses do not directly involve the upper limbs.
Pain, one of the most widely studied outcomes in yoga, improved significantly with yoga. Some37,41,42,44,46 though not all42,43,49 have reported similar results. Yoga was associated with positive affect and fewer depressive symptoms, findings also reported by some37,40,44, though not all42,50. In contrast to Evans, et al37, self-efficacy was not significantly different between groups, perhaps because both groups improved.
In RA, significant reductions in joint counts were observed in both groups. One other study reported reductions in joint counts43; another found no change in C-reactive protein (CRP) with 1 week of yoga at a residential camp49. Together, these results suggest that yoga is unlikely to worsen disease activity. Sensitive measures, such as erythrocyte sedimentation rate, CRP, and interleukin 6, should be included in larger samples to evaluate the effect of yoga on systemic inflammation and immune reactivity.
A strength of our study was the controlled pragmatic study design. Randomization, blinding, concealment of treatment allocation, and use of flexible standardized protocols to guide progression increase confidence in our results. Including typical sedentary participants with RA and OA, evaluating classes specifically designed to promote independent practice, offering the program in community settings, and evaluating the effect on HRQOL increase the applicability and relevance of results. Although our program was developed by a multidisciplinary team (rheumatologists, psychologists, public health, and exercise scientists) and tailored for arthritis, we used common yoga poses and practices and a class length found in many introductory classes. Participants were taught to assess how they felt at each class and to adjust their practice accordingly. We also explored clinician-measured (fitness and clinical signs) and patient-centered (mood, stress, self-efficacy, symptoms) outcomes to gain insight into how yoga may affect health and well-being. Data collected on waitlist participants who later completed yoga supported the RCT findings, and many trends became statistically and clinically significant. In focus groups on RA stiffness that we conducted after five years, several participants commented that yoga had played a pivotal role in changing how they viewed their functioning, capabilities, and attitudes toward living with RA; they credited yoga with helping them maintain a more active lifestyle.
Although our study provides preliminary evidence that yoga appears to be acceptable to people with arthritis and does not aggravate joint disease, caution is warranted. A longer period of practice might produce further gains, though potentially with an increased risk of injury. Despite improvements after 8 weeks, significant impairments were still evident in physical function, role physical, pain, general health, and energy. Classes were taught by experienced yoga therapists in community hospital fitness settings. Because classes began once ∼15 participants were available, the length of time between baseline assessment and the start of yoga classes varied. We did not stratify by diagnosis, randomization did not result in group equivalence in age, and our sensitivity analyses used methods assuming data were missing at random, which we did not confirm. We cannot determine whether some yoga elements had more benefit than others, or the extent to which the yoga group experienced greater social support. Research to replicate and extend these findings across settings, instructors, and in diverse groups is ongoing. Inclusion of biomarkers may provide additional insight. Larger trials with active comparators are needed to establish the relative efficacy of yoga versus traditional exercise and other mind-body practices.
Our study contributes preliminary new evidence that sedentary individuals with RA and knee OA can safely learn to practice yoga in classes led by trained instructors who provide close supervision and individual attention. Eight weeks of classes and home practice was associated with clinically significant improvements in physical and mental health, fitness, psychological function, and HRQOL, with no adverse outcomes. Additional studies with active comparison groups in diverse settings and other forms of arthritis are necessary to support these findings and establish the benefits of yoga in relation to traditional exercise in people with arthritis.
Acknowledgment
We acknowledge the assistance of Heather Keller, Devin Rand-Giovannetti, Chethan Kasargod, Isabel Roth, Michelle Jones, Uzma Haque, Jon Giles, and Joan Bathon.
APPENDIX 1.
Sample class outline.
APPENDIX 2.
Sample modification of yoga poses for people with arthritis.
Footnotes
Supported by the US National Center for Complementary and Alternative Medicine pilot project (Bartlett), US National Institutes of Health predoctoral award 1F31AT003362-01A1, and Arthritis Foundation doctoral dissertation award (Moonaz).
- Accepted for publication January 27, 2015.
