Differences between participants and nonparticipants in an exercise trial for adults with rheumatoid arthritis

Objective. To investigate the generalizability of the results of a randomized controlled trial on the effectiveness of long-term, high-intensity exercises in the rheumatoid arthritis patients in training (RAPIT) trial by comparing the characteristics of the participants with the nonparticipants. Methods. Participants and nonparticipants were mailed questionnaires on sociodemographic characteristics, health status, reasons not to participate, and attitudes toward intensive exercise. Results. The questionnaires from 892 (75%) nonparticipants and 299 (97%) participants were collected. The nonparticipants were slightly older, more often male, and had longer disease duration than the participants. The nonparticipants perceived their disease as more serious, used fewer disease-modifying antirheumatic drugs, had a lower level of education, and a more negative attitude toward intensive exercise. Conclusion. The results of the RAPIT trial might not be generalizable to the entire target population. To promote participation in long-term, high-intensity exercises, health professionals should more actively discuss the potential benefits of exercise with their RA patients while taking into consideration specific factors related to participation.