Aims: Quantitative data on health state utilities in primary hyperoxaluria type 1 (PH1) are lacking. This study was conducted to estimate utility values in PH1 using 3 standard valuation techniques.
Materials and methods: Health state vignettes were developed with input from expert clinicians to describe different stages of chronic kidney disease (CKD) within the setting of PH1, along with a post-combined liver and kidney transplant (CLKT) health state ≥12 months following transplantation. The utility associated with living in each PH1 health state, as described by the vignettes, was evaluated by members of the UK general public using standard utility assessment techniques, including EQ-5D-5L, Visual Analog Scale, and Time Trade-Off.
Results: A similar pattern across the three valuation methods was observed. Utility values were roughly constant from CKD stage 1-3b and then dropped sharply from these states to CKD stage 4. Decreases in utility in the later stages of CKD (stages 4-5) were followed by a recovery in quality of life in the post-CLKT health state.
Limitations: Vignettes may not fully capture the burden of living with PH1.
Conclusions: This study serves as an informative source of data on how the burden of PH1 varies across disease stages of CKD and post-CLKT in patients with PH1. The study findings highlight the unique clinical features of PH1 compared with non-PH1-related CKD, such as the need for earlier and more intensive hemodialysis, the risk of systemic oxalosis, and the potential need for CLKT (as opposed to kidney-only transplant). The impact of PH1 on health-related quality of life, which worsens once hemodialysis is required and systemic disease manifestations occur, is captured in this study using quantitative health state utilities. These data provide an understanding of the impact of PH1 on health-related quality of life and will facilitate health economic evaluation of future treatments.
Keywords: EQ-5D-5L; Health-related quality of life; I; I1; I10; I19; oxalosis; primary hyperoxaluria; rare diseases; time trade-off; utilities.
Primary hyperoxaluria type 1 (PH1) is a rare genetic disease in which the body produces too much oxalate, leading to kidney damage. Over time it can affect other organs such as the bones, the heart, and the eyes. As kidney damage progresses, patients with PH1 eventually need to receive kidney dialysis. New and emerging treatments aim to reduce oxalate production. To assess the economic value of treatments, data are needed on the quality of life of patients in different stages of PH1. This study collected these data using standard valuation methods. First, we developed written descriptions of different stages of PH1 using expert clinical input and information from published studies. Then, members of the UK general public valued the descriptions in three ways: via a survey called EQ-5D-5L (which asks participants about their mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), via EQ-VAS (a visual scale, resembling a ruler, used to rate quality of life), and via time trade-off (in which participants were asked how many years of perfect health they would give up to avoid living in each disease stage described). The results show that PH1 is likely to have a considerable impact on patients’ quality of life, especially in advanced stages, when dialysis is needed and multiple organs are impacted. The study provides measurable estimates of quality of life in people with PH1, which helps healthcare providers, policy makers, and payers understand the disease burden of PH1. The results can also be used in economic evaluation of new treatments.