Vitality and the course of limitations in activities in osteoarthritis of the hip or knee

A longitudinal cohort study with a follow-up period of three years was conducted. Patients (N = 237) with hip or knee osteoarthritis were recruited from rehabilitation centers and hospitals. Body functions, comorbidity, cognitive functioning, limitations in activities and psychological and social factors (mental health, vitality, pain coping and perceived social support) were assessed. Statistical analyses included univariate and multivariate regression analyses. Psychological and social factors were added to a previously developed model with body functions, comorbidity and cognitive functioning.In knee OA, low vitality has a negative impact on the course of self-reported and performance-based limitations in activities, after controlling for somatic and cognitive factors. In hip OA, psychological and social factors had no additional contribution to the model.Low vitality predicts deterioration of limitations in activities in elderly patients with osteoarthritis of the knee, in addition to established somatic and cognitive risk factors. However, the contribution of vitality is relatively small. Results of this study are relevant for the group of patients with knee or hip OA, attending hospitals and rehabilitation centers.Elderly patients with osteoarthritis (OA) of the hip or knee often experience limitations in activities [1,2], which slowly deteriorate [3]. During the first three years of follow-up, limitations in activities are relatively stable [4]. However, there is considerable variation in the course of limitations in activities among individual patients: some patients improve, while others deteriorate. Knowledge about prognostic factors is, therefore, highly relevant in optimizing rehabilitation for elderly patients with hip or knee OA. Research showed that worsening of limitations in activities in the first three years of follow-up is influenced by body functions, comorbidity and to a lesser extent cognitive functioning [4]. Reduced ROM, decreased muscle str