Cost analytic model to determine the least costly inpatient erythropoiesis stimulating therapy regimen

Unlike in outpatient settings, the comparative costs of epoetin alpha (EPO) and darbepoetin alpha (DARB) have not been evaluated broadly from the inpatient hospital perspective.

To develop a cost analytic model comparing hospital inpatient costs for erythropoiesis stimulating therapies within the nephrology and oncology settings.

A cost analytic model incorporating erythropoietic drug, pharmacy, and nursing costs was developed from the inpatient hospital perspective to evaluate comparative costs of EPO and DARB. Erythropoietic drug costs were calculated using unit wholesale acquisition cost multiplied by the number of units or micrograms while comparing the following dosing regimens: EPO 3 times weekly, EPO once weekly, and DARB once weekly. Pharmacy costs included dispensing and delivery costs, while nursing costs incorporated administration time costs; all were calculated by estimated fractional hours per activity multiplied by hourly wages. The total frequency of erythropoiesis stimulating therapy administrations was determined based on the average hospital length of stay. The first erythropoiesis stimulating therapy dose was assumed to occur on day 3 of hospitalization. For total inpatient costs, a weighted average was calculated across disease states. One-way sensitivity analyses were conducted by varying length of stay, day of initial erythropoiesis stimulating therapy dose, pharmacy and nursing costs, and once-weekly DARB dose.

EPO 3 times weekly was the least costly regimen across all disease states evaluated. Threshold analysis indicated that the cost of once-weekly DARB regimens would have to be reduced by 37% to equal the cost of EPO 3 times weekly for an average length of stay. Sensitivity analyses did not considerably affect the results.

EPO 3 times weekly was found to be the least costly erythropoiesis stimulating therapy regimen for nephrology and oncology inpatients for the average length of stay as well as most other lengths of stay considered. Once-weekly EPO was the least costly erythropoiesis stimulating therapy regimen for several other lengths of stay, while once-weekly DARB was never found to be the least costly regimen.