A DECISION-ANALYSIS COMPARING 3 DOSAGE REGIMENS OF SUBCUTANEOUS EPOETIN IN CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

Epoetin (recombinant human erythropoietin; EPO) therapy adds a signifi cant cost to the management of end-stage renal disease, the majority o f the extra expense being attributable to its acquisition cost. In a J apanese multicentre, randomised, prospective study, a significant dose -dependent response was documented with epoetin given subcutaneously ( SC) once a week or once every 2 weeks to patients receiving continuous ambulatory peritoneal dialysis. Three different dosages were studied over 5 months in patients with a haematocrit (Hct) of 0.28 or less, na mely 6000U (107 U/kg), 9000U (167 U/kg) and 12 000U (211 U/kg). Epoeti n was given weekly for the first 2 months until the target Hct value o f 0.33 was reached. The rates of response were 81, 85 and 100% with th e 6000U, 9000U and 12 000U regimens, respectively. Subsequently, respo nders were maintained at the target Hct for an additional 3 months, wi th the administration frequency eventually being reduced to fortnightl y or 4-weekly. Patients in the epoetin 6000U and 9000U groups who did not respond after 2 months' treatment underwent induction and maintena nce with the 12 000U regimen. During the maintenance phase, patients r eceiving the epoetin 6000U and 9000U dosages required weekly (54 and 6 4%, respectively) or fortnightly (46 and 36%, respectively) injections . Patients receiving the 12 000U regimen were found to require weekly (9%), fortnightly (73%) or 4-weekly (18%) injections. Using these data , we performed a decision analysis that quantitatively incorporated th e probability of attaining and maintaining target Hct levels in all pa tients (i.e. the effectiveness of epoetin), and direct costs as a func tion of both cumulative doses and injections required in all 3 strateg ies over 5 months. Decision analysis indicated that the most cost-effe ctive SC epoetin strategy in patients undergoing peritoneal dialysis i s epoetin 6000U weekly for 2 months, followed by maintaining the targe t Hct with weekly or 2-weekly epoetin 6000U for the next 3 months. Non responders should restart epoetin therapy using the 12 000U strategy. The 9000U and 12 000U strategies were associated with similar costs, b ecause the economic advantages associated with the lower administratio n frequency of the 9000U regimen compared with the 6000U regimen were offset by its higher cumulative acquisition cost. In other words, deci sion analysis indicated that the most cost-effective strategy was to u se the lowest effective dose, reserving the highest dosage for patient s who do not respond after 2 months. The superiority of this strategy was confirmed by a sensitivity analysis performed on the cost of drug administration, which was varied from zero to $US60 per dose. In addit ion, consistent results were obtained when the analysis was extended t o cover a 1-year treatment period with all 3 strategies.