Background: There is uncertainty about the most cost-effective way to treat hyperphosphataemia in patients with end-stage renal disease. Methods. We performed an economic analysis which compared the use of sevelamer with calcium carbonate in a simulated cohort of North American dialysis patients, using the perspective of the health care purchaser and a lifetime horizon. Outcomes considered were quality-adjusted life years (QALYs) gained and health care costs. To account for uncertainty, we considered four separate modelling strategies, obtaining data on the relative effectiveness of sevelamer from the recent Dialysis Clinical Outcomes Revisited study.
Results: In the base analysis, the use of sevelamer was associated with a cost per QALY gained of CAN$157,00, compared with calcium carbonate. Assuming no survival or hospitalization advantage for sevelamer, use of sevelamer resulted in an incremental cost of CAN$17,00 per patient. In alternate models which assumed sevelamer to be more effective than calcium-based phosphate binders, the use of sevelamer was associated with a cost per QALY gained ranging from CAN$127,00-$278,00. Assuming that sevelamer resulted in a differential reduction in mortality in patients > or = 65 years of age, use of sevelamer in this subgroup was associated with a cost per QALY of CAN$105,500. Results were similar in groups defined by age > or = 55 or by > or = 45 years. Since dialysis is expensive, interventions for dialysis patients that improve survival without reducing the need for dialysis will be associated with a cost-utility ratio at least as great as that of dialysis itself. As such, we repeated the primary analysis excluding the costs of dialysis and transplantation and found that the cost per QALY gained for sevelamer was $77,600.
Conclusions: The cost per QALY gained for treating all dialysis patients with sevelamer exceeds what would usually be considered good value for the money. While the high cost per QALY was in part due to the inclusion of the costs of dialysis and transplant in the analysis, the cost per QALY gained remained relatively unattractive even when these costs were excluded. Although a lower cost per QALY gained is realized when only patients older than 65 years are treated, this strategy remains economically unattractive, particularly given the uncertainty of clinical benefit in this group.