Socioeconomic differences in patient-reported outcomes after a hip or knee replacement in the English National Health Service.

BACKGROUND: We investigated socioeconomic differences in patient-reported outcomes after a hip or knee replacement and the contribution of health differences beforehand.
METHODS: Our sample included 121 983 patients in England who had an operation in 2009-2011. Socioeconomic status was measured with quintiles of the ranking of areas by the English Index of Multiple Deprivation. Outcomes at 6 months were the Oxford hip or knee score (OHS or OKS) that measure pain and disability on a scale from 0 (worst) to 48 (best), and the percentage reporting no improvement in problems. Adjustment was made for age, sex, ethnicity, comorbidity, general health, revision surgery, primary diagnosis, preoperative OHS or OKS and having longstanding problems.
RESULTS: Comparing the most- with the least-deprived group, the mean OHS was 5.0 points lower and the OKS 5.4 lower. Adjusted differences, reflecting the differences in improvement in the condition, were 2.8 [95% confidence interval (CI): 2.5-3.0] on OHS and 2.4 (95% CI: 2.2-2.7) on OKS. Adjusted odds ratios for reporting no improvement were 1.4 (1.2-1.6) for the hip and 1.4 (1.3-1.5) for the knee.
CONCLUSIONS: On average, patients living in socioeconomically deprived areas had worse outcomes after surgery, partly related to preoperative differences in health and disease severity and partly to less postoperative improvement.