Cost utility analysis of erythropoietin for anemia treatment in hemodialysis patients at Siriraj Hospital

Abstract

The purpose of this study was to evaluate the cost utility analysis of EPO for maintaining the different hemoglobin target levels in anemic hemodialysis patients in routine clinical practice. In cost utility analysis (CUA), there were two important variables involved: cost and utility of HD patients using erythropoietin (EPO). Face-to-face interview using KDQOL-SF (SF-36 and kidney disease specific questionnaire) and EQ-5D was conducted during November-December 2009 with 152 hemodialysis patients. The mean SF-6D score was 0.748±0.139 showing significantly higher than EQ-5D (0.704±0.341), and VAS (0.684±0.191) scores. Pearson’s correlation coefficients between utility scores with kidney disease specific questionnaires illustrated that all three utility scores were correlated well with the symptoms and problems dimension, but had low association with the burden and effects of kidney disease on daily life dimension. The SF-6D presented better agreement with kidney specific scales than EQ-5D and VAS. The average utility scores of SF-6D were significantly different across Hb levels (ANOVA, p=0.005) while other utility scores were not significant different (p>0.05). These findings implied that SF-6D could, to a certain extent, reflect HRQoL status of hemodialysis patients and might be used as the input parameter in the analysis. Another input parameter was transitional probabilities that were obtained mainly from a systematic review and meta-analysis. The data showed that using EPO for maintaining the different Hb levels did not indicate a significant effect on increasing cardiovascular (CV) events or CV mortality rate in HD patients without the history of CV events but showed a significant effect on increasing CV mortality rate in HD patients with CV history. The direct medical cost was estimated based on the reference price of the Siriraj hospital and direct non-medical costs were from the structured questionnaire interviews. After derived all input parameters, the Markov model was used to estimate the incremental cost and Quality Adjusted Life Year (QALY) associated with EPO treatment for maintaining hemoglobin levels of >9-10, >10-11, >11-12, and >12 g/dl, comparing with 9 g/dl and adopting both the hospital and the societal perspectives. All future costs and outcomes were discounted at the rate of 3% per annum. When providing EPO to raise the Hb level up to >10 to 11 g/dl, up from the initial Hb of less than 9 g/dl, yields the minimum incremental cost per QALY in the hospital and societal perspective about 492,808.59 and 609,997.53 Baht per QALY, respectively. From PSA, Hb level >10 to 11 g/dl was the optimal choice at the willingness to pay (WTP) at 420,000-1,285,000 and 503,750-1,512,500 Baht with the probability of cost effective was 31.43-96.17%, and 29.32-95.94% for the hospital and the societal perspectives, respectively. The findings should be proposed to policy decision makers to set up the guideline for appropriate and cost-effective use of EPO in the hospital as well as to establish the reimbursement criteria for EPO use at the national level.