Long-term effectiveness of a lifestyle intervention for rheumatoid arthritis and osteoarthritis: 1-year follow-up of the ‘Plants for Joints’ randomised clinical trial

Objectives In two randomised controlled trials, the Plants for Joints (PFJ) multidisciplinary lifestyle intervention reduced signs and symptoms of rheumatoid arthritis (RA), or metabolic syndrome-associated hip or knee osteoarthritis (MSOA) compared with usual care. The current study investigated long-term outcomes.Methods After completion of two 16-week trials in people with (1) RA or (2) MSOA, control groups switched to the active PFJ intervention. At the end of the intervention, all participants were followed up in a 1-year observational extension study. Primary outcomes were 28-joint Disease Activity Score (DAS28) (RA) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (MSOA). Secondary outcomes included body composition, metabolic outcomes, medication changes and intervention adherence. An intention-to-treat analysis with a linear mixed model was used to analyse within-group changes.Results 65 (84%) of 77 RA participants and 49 (77%) of 64 MSOA participants completed the extension study. The effects of the PFJ intervention were replicated in the original control groups and sustained within the RA group a year after intervention completion (mean DAS28 –0.9 points; p