External Validation of Achieving the Patient Acceptable Symptom State for the EuroQol-5 Dimension 1 Year After Total Hip Arthroplasty

BACKGROUND: Patient acceptable symptom state (PASS) thresholds for the EuroQol-5 Dimension-3 Level (EQ-5D-3L) questionnaire have been established for patients being evaluated 1 year following total hip arthroplasty (THA) but with varying derivation cohorts and methods. The aim of this study was to (1) generate an EQ-5D PASS threshold 1 year following THA on the basis of an international patient cohort, (2) validate preexisting and newly generated PASS thresholds 1 year following THA using the institutional registry of an academic care center, and (3) assess whether THA PASS thresholds vary by patient age and sex.

METHODS: The derivation cohort for the THA PASS threshold consisted of 774 patients (after exclusions) who were enrolled in an international, multicenter study from 2007 to 2012 and who completed the EQ-5D and a numerical rating scale (NRS) for satisfaction 1 year postoperatively. With the NRS dichotomized at 2.5 as the anchor, a PASS cutoff for the EQ-5D was generated using the 80% specificity method. The Youden method and 75th percentile approach served as sensitivity analyses. The external validation cohort comprised 1,472 patients who had undergone THA. PASS thresholds were used to dichotomize the external validation sample. The ability of the threshold to predict satisfaction was evaluated with receiver operating characteristic (ROC) curve analysis. Patient subcohorts were stratified by age (>65 and ≤65 years) and sex.

RESULTS: Three THA PASS thresholds of 0.77 (our newly defined threshold), 0.82, and 0.92 were validated in this study. The EQ-5D PASS threshold of 0.77 (area under the curve [AUC] = 0.816) best predicted satisfaction 1 year after THA. Subcohort analyses yielded comparable 1-year PASS thresholds for THA between age cohorts and between sex cohorts.

CONCLUSIONS: This study identifies PASS thresholds that best predict patient satisfaction 1 year following THA. Although the varied methodology and patient cohorts used to derive PASS values complicate the comparison of these thresholds, this analysis can help surgeons understand the level of health-related quality of life associated with patient satisfaction following THA.

LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.