The Effects of Vitamin D and Marine Omega-3 Fatty Acid Supplementation on Chronic Knee Pain in Older US Adults: Results From a Randomized Trial.

OBJECTIVE: Knee pain from osteoarthritis is frequent in the adult population. Prior trials have had conflicting results concerning the therapeutic effects of vitamin D on knee pain, and few trials have investigated marine Omega-3 fatty acids (n-3 FA). METHODS: In the double-blind, placebo-controlled Vitamin D and Omega-3 Trial (VITAL), 25,871 US adults were randomized in a 2-by-2 factorial design to receive vitamin D or n-3 FA. We identified a subgroup with chronic knee pain prior to randomization and assessed knee pain at baseline and annually during follow-up using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (graded on a 0-100 scale, where 100 indicates worst symptoms). Repeated measures modeling was used to test the effect of randomized treatment on WOMAC pain scores over follow-up after adjustment for age and sex. Analyses were repeated for WOMAC function and stiffness. RESULTS: This study included 1,398 participants who returned at least one knee pain questionnaire. The mean age was 67.7 years, 66% were women, and the mean ± SD WOMAC pain score was 37 ± 19. The mean ± SD follow-up time was 5.3 ± 0.7 years. WOMAC pain did not differ between the active vitamin D group and the vitamin D placebo group or between the active n-3 FA group and the n-3 FA placebo group at any time point during follow-up. Linear time-by-treatment interactions were not significant for either treatment (vitamin D, P = 0.41; n-3 FA, P = 0.77). Vitamin D and n-3 FA supplementation did not significantly affect WOMAC function or stiffness scores over time. CONCLUSION: Our findings indicate that vitamin D and n-3 FA supplementation for a mean of 5.3 years does not reduce knee pain or improve function or stiffness in a large sample of US adults with chronic knee pain.

Dose-Response Effects of Tai Chi and Physical Therapy Exercise Interventions in Symptomatic Knee Osteoarthritis.

BACKGROUND: Therapeutic exercise is a currently recommended nonpharmacological treatment for knee osteoarthritis (KOA). The optimal treatment dose (frequency or duration) has not been determined. OBJECTIVE: To examine dose-response relationships, minimal effective dose, and baseline factors associated with the timing of response from 2 exercise interventions in KOA. DESIGN: Secondary analysis of a single-blind, randomized trial comparing 12-week Tai Chi and physical therapy exercise programs (Trial Registry #NCT01258985). SETTING: Urban tertiary care academic hospital PARTICIPANTS: A total of 182 participants with symptomatic KOA (mean age 61 years; BMI 32 kg/m2, 70% female; 55% white). METHODS: We defined dose as cumulative attendance-weeks of intervention, and treatment response as ≥20% and ≥50% improvement in pain and function. Using log-rank tests, we compared time-to-response between interventions, and used Cox regression to examine baseline factors associated with timing of response, including physical and psychosocial health, physical performance, outcome expectations, self-efficacy, and biomechanical factors. MAIN OUTCOME MEASURES: Weekly Western Ontario and McMasters Osteoarthritis Index (WOMAC) pain (0-500) and function (0-1700) scores. RESULTS: Both interventions had an approximately linear dose-response effect resulting in a 9- to 11-point reduction in WOMAC pain and a 32- to 41-point improvement in function per attendance-week. There was no significant difference in overall time-to-response for pain and function between treatment groups. Median time-to-response for ≥20% improvement in pain and function was 2 attendance-weeks and for ≥50% improvement was 4-5 attendance-weeks. On multivariable models, outcome expectations were independently associated with incident function response (hazard ratio = 1.47, 95% confidence interval 1.004-2.14). CONCLUSIONS: Both interventions have approximately linear dose-dependent effects on pain and function; their minimum effective doses range from 2-5 weeks; and patient perceived benefits of exercise influence the timing of response in KOA. These results may help clinicians to optimize patient-centered exercise treatments and better manage patient expectations. LEVEL OF EVIDENCE: II.

Comparative Effectiveness of Tai Chi Versus Physical Therapy for Knee Osteoarthritis: A Randomized Trial.

BACKGROUND: Few remedies effectively treat long-term pain and disability from knee osteoarthritis. Studies suggest that Tai Chi alleviates symptoms, but no trials have directly compared Tai Chi with standard therapies for osteoarthritis. OBJECTIVE: To compare Tai Chi with standard physical therapy for patients with knee osteoarthritis. DESIGN: Randomized, 52-week, single-blind comparative effectiveness trial. (ClinicalTrials.gov: NCT01258985). SETTING: An urban tertiary care academic hospital. PATIENTS: 204 participants with symptomatic knee osteoarthritis (mean age, 60 years; 70% women; 53% white). INTERVENTION: Tai Chi (2 times per week for 12 weeks) or standard physical therapy (2 times per week for 6 weeks, followed by 6 weeks of monitored home exercise). MEASUREMENTS: The primary outcome was Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 12 weeks. Secondary outcomes included physical function, depression, medication use, and quality of life. RESULTS: At 12 weeks, the WOMAC score was substantially reduced in both groups (Tai Chi, 167 points [95% CI, 145 to 190 points]; physical therapy, 143 points [CI, 119 to 167 points]). The between-group difference was not significant (24 points [CI, -10 to 58 points]). Both groups also showed similar clinically significant improvement in most secondary outcomes, and the benefits were maintained up to 52 weeks. Of note, the Tai Chi group had significantly greater improvements in depression and the physical component of quality of life. The benefit of Tai Chi was consistent across instructors. No serious adverse events occurred. LIMITATION: Patients were aware of their treatment group assignment, and the generalizability of the findings to other settings remains undetermined. CONCLUSION: Tai Chi produced beneficial effects similar to those of a standard course of physical therapy in the treatment of knee osteoarthritis. PRIMARY FUNDING SOURCE: National Center for Complementary and Integrative Health of the National Institutes of Health.

Assessing the comparative effectiveness of Tai Chi versus physical therapy for knee osteoarthritis: design and rationale for a randomized trial.

BACKGROUND: Knee osteoarthritis (OA) causes pain and long-term disability with annual healthcare costs exceeding $185 billion in the United States. Few medical remedies effectively influence the course of the disease. Finding effective treatments to maintain function and quality of life in patients with knee OA is one of the national priorities identified by the Institute of Medicine. We are currently conducting the first comparative effectiveness and cost-effectiveness randomized trial of Tai Chi versus a physical-therapy regimen in a sample of patients with symptomatic and radiographically confirmed knee OA. This article describes the design and conduct of this trial. METHODS/DESIGN: A single-center, 52-week, comparative effectiveness randomized controlled trial of Tai Chi versus a standardized physical-therapy regimen is being conducted at an urban tertiary medical center in Boston, Massachusetts. The study population consists of adults ≥ 40 years of age with symptomatic and radiographic knee OA (American College of Rheumatology criteria). Participants are randomly allocated to either 12 weeks of Tai Chi (2x/week) or Physical Therapy (2x/week for 6 weeks, followed by 6 weeks of rigorously monitored home exercise). The primary outcome measure is pain (Western Ontario and McMaster Universities WOMAC) subscale at 12 weeks. Secondary outcomes include WOMAC stkiffness and function domain scores, lower extremity strength and power, functional balance, physical performance tests, psychological and psychosocial functioning, durability effects, health related quality of life, and healthcare utilization at 12, 24 and 52 weeks. DISCUSSION: This study will be the first randomized comparative-effectiveness and cost-effectiveness trial of Tai Chi versus Physical Therapy in a large symptomatic knee OA population with long-term follow up. We present here a robust and well-designed randomized comparative-effectiveness trial that also explores multiple outcomes to elucidate the potential mechanisms of mind-body effect for a major disabling disease with substantial health burdens and economic costs. Results of this study are expected to have important public health implications for the large and growing population with knee OA. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01258985.