BACKGROUND & OBJECTIVE
Exercise is strongly recommended in the conservative management of knee osteoarthritis (OA). However, heterogeneity in treatment response is poorly understood. Group-based trajectory modeling can determine patterns of longitudinal change over increasing treatment exposure. The latter may help to identify subgroups of patients that may require more monitoring to encourage better adherence, as well as those who do not respond to exercise. Therefore, the aims of this study were to:
- Identify subgroups of individuals with symptomatic knee OA who have similar trajectories in pain and physical function over up to 12 weeks of exercise.
- Characterize those participants and their pain and functional trajectories.
- Explore the associations of pain and functional trajectories with baseline factors of health.
A prospective cohort of 171 participants (mean age 61 years; BMI 32 kg/m2, 71% female) with symptomatic knee OA from a previous RCT comparing 12 weeks of Tai Chi and Physical Therapy were the subjects in this study. The authors analyzed weekly Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain (0-500) and function (0-1700) scores using group-based trajectory models. Associations between baseline factors and trajectories were examined using multinomial logistic regression.
The authors identified four pain trajectories: 1. Lower Pain Level-Early Improvement (43%)