Background and Objectives A preference-based health utility score (PROPr) can be calculated using Patient-Reported Outcomes Measurement Information System domain scores. We assessed the construct validity of PROPr among patients treated with kidney replacement therapy (hemodialysis or kidney transplant).
Design, setting, participants and measurements Secondary analysis of data collected in multicenter, cross-sectional studies of adults treated with kidney replacement therapy, recruited between April 2016 to March 2020 in Toronto, Canada. All participants provided informed consent. The outcome was PROPr score. Co-administered outcome variables included the Short form 6-domain (SF-6D) and EuroQol 5-domain 5-level (EQ-5D-5L) scores. Socioeconomic and clinical variables included age, sex, diabetes, estimated Glomerular Filtration Rate (eGFR), serum albumin, hemoglobin, kidney replacement therapy and Charlson-comorbidity index. Construct validity was assessed through correlations between PROPr and SF-6D or EQ-5D-5L and associations between PROPr and other exposure variables. Health condition impact estimates (coefficients for health conditions compared to a referent category: e.g. dialysis vs kidney transplant) were calculated using multivariable linear regression.
Results Mean (SD) age of the 524 participants was 57 (17) years, 58% were male and 45% white. Median (IQR) score was 0.39 (0.24-0.58) for PROPr, 0.69 (0.58-0.86) for SF-6D and 0.85 (0.70-0.91) for EQ-5D-5L. Large correlations were observed between PROPr vs SF-6D (0.79, 95%CI: 0.76 - 0.82) and EQ-5D-5L (0.71, 95%CI: 0.66 - 0.75). Both PROPr and the other utility indices demonstrated health condition impact in the expected direction. For example, the estimate for PROPr was -0.17 (95%CI: -0.13, -0.21) for dialysis (versus kidney transplant), -0.05 (95%CI: -0.11, 0.01, P=0.08) for kidney transplant recipients with eGFR <45 vs ≥45 ml/min/1.73m2 and -0.28 (95%CI: -0.22, -0.33) for moderate/severe versus no/mild depressive symptoms.
Conclusions Our results support the validity of PROPr among patients treated with kidney replacement therapy.