Partner and Relationship Predictors of Longitudinal Physical Activity Trajectories Among Individuals with Osteoarthritis Using Latent Class Growth Analysis.

Background Physical activity reduces osteoarthritis symptoms, yet many individuals with the disease are insufficiently active. Purpose We identified physical activity trajectories over 12 months of individuals with osteoarthritis and examined how their cohabiting spouses'/partners' baseline physical activity and relationship factors affected trajectory membership. Methods In this longitudinal observational study, we collected data from 168 adults with knee/hip osteoarthritis. We used latent class growth curve analysis to identify physical activity trajectories and logistic regression to predict trajectory membership using partners' physical activity, relationship satisfaction, and communal coping (belief that both partners are responsible for osteoarthritis management). Measures, including objectively assessed physical activity, were collected at baseline from the couple, who then received an educational class on physical activity and social support. Objectively assessed physical activity was also collected from individuals with osteoarthritis at 1 week, 3 months, 6 months, and 12 months post-baseline. Results Three trajectories were identified: stable active, increaser, and stable sedentary (24%, 40%, 37% of participants, respectively). Individuals with osteoarthritis with partners who were more active and who believed they alone were responsible for their osteoarthritis were more likely to follow the stable active (versus stable sedentary) trajectory. Those with partners who were less active and had higher relationship satisfaction were more likely to follow the increaser (vs. stable active) trajectory. Conclusions Findings demonstrate the importance of considering partner and relationship factors in physical activity interventions for couples.