Illness perceptions and their association with 2 year functional status and change in patients with hand osteoarthritis

To investigate the association between illness perceptions and disability both cross-sectionally and over 2 years in patients with hand OA. Illness perceptions and self-reported disability were assessed at baseline and after 2 years in 384 patients with primary hand OA (mean age 61 years, 84% women, n = 312 with follow-up) with the Illness Perception Questionnaire – Revised (IPQ-R), Functional Index for Hand OA, Australian/Canadian Hand OA Index and HAQ. Risk ratios for high disability (highest quartile) at both time points were estimated for tertiles of IPQ-R dimensions, using Poisson regression. The mean IPQ dimension change difference between patients with and without disability progression (change Functional Index for Hand OA ⩾ 1, Australian/Canadian Hand OA Index > 1.4, HAQ > 0.22) was estimated with linear regression. Analyses were adjusted for age, Doyle index and baseline score. At baseline, stronger negative illness perceptions were associated with high disability. Baseline illness perceptions were also associated with high disability after 2 years, although adjustment made apparent that these associations were confounded by baseline disability status. Most illness perceptions changed over 2 years; understanding increased, OA was regarded as more chronic and fewer emotions and consequences and less personal and treatment control were experienced. The 2 year change in disability was different between patients with and without progression for the illness perceptions of more perceived consequences, symptoms, treatment control and emotions. Illness perceptions seemed to be implicated in disability and its progression. Our results suggest that interventions could focus on improving baseline disability, potentially using illness perceptions to accomplish this goal.