Using the common sense model of illness perceptions to examine osteoarthritis change: a 6-year longitudinal study.

Objective: To examine the association between changes in common sense models and changes in functional status over a 6-year follow-up in patients with osteoarthritis.

Design: At baseline and follow-up, osteoarthritis outpatients (N = 241) recruited from a university medical center completed the Illness Perception Questionnaire-Revised (IPQ-R), the Australian/Canadian Osteoarthritis Hand Index, and the Western Ontario and McMasters Universities Osteoarthritis Index. Also, their physician-assessed pain intensity, and biomedical, and clinical measures of medical severity of osteoarthritis were recorded.

Main Outcome Measures: Functional disability, pain intensity.

Results: Over 6 years, functional disability and pain intensity increased. The IPQ-R dimensions of timeline, personal control, and illness coherence became more negative, and emotional representations became less negative (i.e., more accepting). Patients identified as sharing a similar profile of negative changes on the IPQ-R had significantly worse functioning on 2 of 3 outcomes, independent of objectively measured osteoarthritis severity.

Conclusions: Changes in illness perceptions were associated with changes in outcomes. Interventions to prevent increasingly negative patterns of illness perceptions over time, with an emphasis on strengthening control cognitions, may benefit functional status outcomes in patients with osteoarthritis.