Estimation of Health State Utility Values for Immunoglobulin A Nephropathy: A Time Trade-Off Analysis.

Background: Immunoglobulin A nephropathy (IgAN) is a rare progressive disease that can lead to kidney failure. The current study aimed to estimate health state utility values for IgAN from a UK societal perspective.

Methods: We used the time trade-off (TTO) method to derive utility values for various health states in IgAN, defined based on chronic kidney disease (CKD) stage, proteinuria, dialysis, and nephrotic syndrome (CKD stages 1-4, proteinuria < 1 g/day vs ≥ 1 g/day; CKD stage 5, dialysis vs non-dialysis). We developed health state vignettes to describe typical symptoms and quality-of-life impairments of IgAN. Eligible participants from the UK general public completed a computer-assisted telephone interview. Estimated TTO utility values were reviewed against visual analogue scale (VAS)-derived values.

Results: In total, 200 participants were included in the study (mean age, 48.9 years; female, 59.0%). Mean (standard deviation [SD]) utility values were 0.84 (0.17) and 0.71 (0.23) for CKD stage 1/2 with proteinuria < 1 g/day and with proteinuria ≥ 1 g/day, respectively; 0.68 (0.23) and 0.61 (0.25) for CKD stage 3; and 0.55 (0.26) and 0.49 (0.27) for CKD stage 4. Mean (SD) utility of CKD stage 5 with and without dialysis was 0.38 (0.30) and 0.42 (0.28), respectively. The mean (SD) utility value of nephrotic syndrome was 0.43 (0.33).

Conclusions: Our results indicated that various IgAN health states are associated with impaired health status, with substantial utility decrements related to disease progression, elevated proteinuria, and nephrotic syndrome.