Radiographic knee osteoarthritis impacts multiple dimensions of health-related quality of life: data from the Osteoarthritis Initiative

Objectives. To estimate the multi-dimensional health impact of radiographic knee OA and quantify the overall health-related quality of life (HRQoL) burden, using a preference-based health utilities measure. Methods. Data on self-reported HRQoL, measured using the SF-12 multi-dimensional health state instrument, were obtained for 2895 patients with radiographic knee OA (Kellgren-Lawrence grade of at least 2) from the Osteoarthritis Initiative and for a general population sample of 3202 from the National Health Measurement Study. The SF-12 was converted to the six-dimensional SF-6D classification to compute preference-based health utilities. Generalized ordinal regression and multinomial regression were used to estimate the health loss on each SF-6D dimension for Osteoarthritis Initiative participants with radiographic knee OA relative to the general population, adjusted for differences in age, BMI, sex, ethnicity and educational level. Predicted SF-6D profiles were then used to compute the average HRQoL loss attributable to radiographic knee OA. Results. Radiographic knee OA was associated with substantial health losses on all dimensions of the SF-6D except for social functioning. Health losses increased with the radiographic severity of OA in dimensions related to physical health, while there was no relationship between worse radiographic disease and worse self-assessed health in mental and emotional dimensions of health. Overall, radiographic knee OA was associated with a HRQoL detriment of 0.040-0.044 at Kellgren-Lawrence grade 2, increasing to 0.045-0.050 at grade 3 and 0.073-0.081 at grade 4. Conclusion. Radiographic knee OA is significantly associated with worse HRQoL across most dimensions of health.