Purpose: No interventions to promote physical activity can succeed for all participants. Insights into the specific characteristics of those who do succeed are needed. One aim was to investigate whether a selection of correlates of general health perception creates cluster typologies in individuals with rheumatoid arthritis (RA). Another was to evaluate whether magnitude of change in health status differs between clusters after a 1-year coaching intervention targeting health-enhancing physical activity.
Method: Two hundred and twenty-eight patients (74% women, mean age 56 years, disease duration 1 year) with RA, from 10 rheumatology clinics in Sweden, participated. The patients were assigned at random to intervention or control. The intervention group underwent 1 year of coaching to adopt health-enhancing physical activity (moderately intensive, 30 min/day, > 4 days/week). The cluster analysis included five correlates of general health perception: disease activity; pain; timed standing; activity limitation; and self-reported physical activity. The primary outcome of the coaching intervention was self-reported health status.
Results: One-hundred and forty-six patients were eligible for inclusion in the cluster analysis. The eight clusters identified both at baseline and post interventions were operationalized according to the number of cluster variables affected: less (LE) affected or more (MO) affected, respectively. Clusters with LE affected variables had significantly better general health perception at baseline than those with MO affected variables. Further, coached individuals in MO affected clusters significantly improved self-reported health status compared both to those coached in LE affected clusters and to those in MO affected clusters in the control group.
Conclusion: This person-based approach contributed more than did the results in a previous randomized controlled trial to the understanding of which patients benefit most from the present physical-activity coaching intervention. The intervention may thus be most beneficial for individuals more severely affected by their disease at baseline.