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

ABSTRACT

Objective: To investigate the association between illness perceptions and disability both cross-sectionally and over 2 years in patients with hand OA. Methods: 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. Results: 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. Conclusion: 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.