Two-Year Follow-Up of a Multidisciplinary Lifestyle Intervention for Rheumatoid Arthritis and Osteoarthritis.

Objective: The Plants for Joints (PFJ) intervention, including a whole-food plant-based diet, exercise, and stress reduction, reduced signs and symptoms of rheumatoid arthritis (RA) or metabolic syndrome-associated hip or knee osteoarthritis (MSOA) compared to usual care. This study aimed to examine outcomes two years after the PFJ intervention.

Methods: After two 16-week randomized controlled trials in people with (1) RA or (2) MSOA, control groups received the active PFJ intervention. All participants were then observed in a two-year observational extension study. Primary outcomes were Disease Activity Score in 28 joints (DAS28) (RA) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (MSOA). Secondary outcomes included body composition, metabolic outcomes, medication changes, and adherence to intervention recommendations. Within-group differences were assessed using linear mixed models, comparing the start and end of the intervention to two years after intervention.

Results: A total of 48 of 77 participants with RA (62%) and 44 of 64 participants with MSOA (69%) completed the extension study. Two years after the intervention, the DAS28 in participants with RA (-0.9 points, 95% confidence interval [CI] -1.2 to -0.6 points) and WOMAC score in participants with MSOA (-8.8 points, 95% CI -12.6 to -5.1 points) were significantly lower than start intervention. In addition, C-reactive protein in the RA group and weight, body mass index, waist circumference, and diastolic blood pressure in the MSOA group were significantly lower compared to start intervention. Primary end points remained similar from the end of the intervention to the end of the extension study. During the extension study, medication use decreased slightly, and participants continued to follow the intervention recommendations.

Conclusion: Two years after the PFJ intervention, improvements in RA disease activity, MSOA symptoms and functioning, and intervention adherence were sustained.