Participation in a randomised controlled trial for older adults with osteoarthritis in Portugal: Analysis of the acceptance factors.

Fit & Strong! is an evidence-based program that combines exercise with health education for older adults with lower extremity osteoarthritis. This paper explores the factors of acceptance to a randomised controlled trial that tested the Portuguese (Europe) version of Fit & Strong! and analysed the sociodemographic, lifestyle and health characteristics of people who agreed versus people who declined to participate. Patients were identified by General Practitioners at three healthcare centres during 4 months (May 2017 to July 2017). Patients who accepted the invitation and met the inclusion criteria are designated participants, and people who met the inclusion criteria, declined the opportunity to participate but agreed to answer a brief questionnaire are designated as non-participants. Data included sociodemographic, lifestyle behaviours, health, pain and ADLs from the Western Ontario and McMaster Universities Osteoarthritis. Data were analysed using descriptive analysis and the Wilcoxon-Mann-Whitney, Chi-Squared tests or Fisher's tests. The results showed that three out of 12 (25%) primary healthcare centres contacted about the new program accepted the invitation to participate in recruitment. Eighty-two patients were contacted, of whom 14 (17.2%) did not meet inclusion criteria and 32 (38.3%) met the inclusion criteria but declined to participate. The acceptance rate was 22%. Non-participants were older (U = 41.0; W = 212.0; p = .044) and experienced earlier osteoarthritis onset than participants (U = 26.0; W = 146.0; p = .031). In conclusion, younger age and a diagnosis of osteoarthritis more recent appear to predispose older adults with osteoarthritis to be more accepting of participation in a non-pharmacologic intervention designed to increase physical activity.