Determinants of self-reported health status in a population-based sample of persons with radiographic knee osteoarthritis.

OBJECTIVE

Knee osteoarthritis (OA) is highly prevalent and disabling. Patients with radiographic knee OA may experience pain and functional impairment, which can diminish their health status. Our objective was to determine factors associated with self-reported health status in a national population-based sample with radiographic knee OA.

METHODS

Our sample included all of the Third National Health and Nutrition Examination Survey (NHANES-III) participants who underwent a knee radiograph and were found to have radiographic OA (defined as Kellgren/Lawrence grade 2 or higher). Self-reported health status was determined by asking the participant to rate their overall health as excellent, very good, good, fair, or poor. Self-reported health status was analyzed as an ordinal variable using cumulative logit regression, as a dichotomous variable (excellent/very good/good versus fair/poor) using logistic regression, and as a continuous variable after transformation using linear regression.

RESULTS

A total of 1,021 (42%) of NHANES-III participants with a knee radiograph were included in this analysis. The multivariable analyses were performed on 1,009 (99%) of the eligible participants with complete data. We found that nonwhite race, lower income, more comorbidities, and greater functional limitation were associated with worse self-reported health status in all 3 multivariable analyses.

CONCLUSION

This study has quantified the role of clinical, radiographic, and socioeconomic factors associated with self-reported health status in a population-based sample of patients with knee OA. Self-reported health status in patients with knee OA was associated with functional status and comorbidity.