A longitudinal validation of the EQ-5D-5L and EQ-VAS stand-alone component utilising the Oxford Hip Score in the Australian hip arthroplasty population

Abstract

Purpose: To evaluate the measurement properties of the Oxford Hip Score (OHS), EQ-5D-5L utility index and EQ- 5D-5L visual analogue scale (EQ-VAS) in patients undergoing elective total hip arthroplasty in Australia. Methods: In this prospective multi-centre study, the OHS and EQ-5D-5L were collected preoperatively, six weeks (6w) and six months (6m) postoperatively. The OHS, EQ-VAS and EQ-5D-5L index were evaluated for concurrent validity, predictive validity (Spearman’s Rho of predicted and observed values from a generalised linear regression model (GLM)), and responsiveness (effect size (ES) and standard response mean (SRM)). Results: 362 patients were included in this analysis for 6w and 269 for 6m. The EQ-5D-5L index showed good concurrent validity with the OHS (r = 0.71 preoperatively, 0.61 at 6w and 0.59 at 6m). Predictive validity for EQ-5D-5L index was similar to OHS when regressed (GLM). Responsiveness was good at 6w (EQ-5D-5L index ES 1.53, SRM 1.40; OHS ES 2.16, SRM 1.51) and 6m (EQ-5D-5L index ES 1.88, SRM 1.70; OHS ES 3.12, SRM 2.24). The EQ-VAS returned poorer results, at 6w an ES of 0.75 (moderate) and SRM 0.8. At 6m the EQ-VAS had an ES of 0.92 and SRM of 1.00. It, however, had greater predictive validity. Conclusions: The EQ-5D-5L index and the OHS demonstrate strong concurrent validity. The EQ-5D-5L index demonstrated similar predictive validity at 6w and 6m, and both PROMs had adequate responsiveness. The EQ-VAS should be used routinely together with the EQ-5D-5L index. The EQ-5D-5L is suitable to quantify health-related quality of life in Australian hip arthroplasty patients.