BACKGROUND:
Economic modeling guidelines recommend use of ‘half-cycle correction’ to be built into the analysis, to account for the fact that events and transitions can occur at any point during the cycle, not necessarily at the start or end of each cycle. For products indicated for chronic heart failure with reduced ejective fraction (HFrEF) half-cycle correction might be of increased importance to capture effect of survival gains and reduction in hospitalizations.
AIM:
To understand the importance and effect of half-cycle correction in cost-effectiveness analysis for Sacubitril/Valsartan vs Enalapril in HFrEF.
METHODS:
We developed a Markov model that captures mortality and heart failure (HF) and non-HF hospitalizations. US patients with HFrEF similar to those in the PARADIGM-HF trial were included in the model. Risks of all-cause mortality and hospitalization from HF or other reasons were estimated with a 30-year time horizon. Quality of life was based on trial EQ-5D scores. Hospital costs combined Medicare and private insurance reimbursement rates; medication costs included the wholesale acquisition cost for sacubitril/valsartan and enalapril. A discount rate of 3% was used. Sensitivity analyses were performed on key inputs including: hospital costs, mortality benefit, hazard ratio for hospitalization reduction, drug costs, and quality-of-life estimates. Two scenarios, with and without half-cycle correction were tested.
RESULTS:
For the model without half-cycle correction, the undiscounted life years (LYs) for Sacubitril/Valsartan and Enalapril were, 11.27 and 9.77 years, respectively, an increase of 1.46 years (similar to 1.43 years reported in Gaziano 2016 model). Applying the half-cycle correction, the undiscounted LYs for Sacubitril/Valsartan and Enalapril were, 11.23 and 9.73 years, respectively, an increase of 1.50 years. Half-cycle increased the estimates for incremental undiscounted LYs by 3.3%. Similarly, for the model without half-cycle correction, the discounted Quality Adjusted Life Years (QALYs) for Sacubitril/Valsartan and Enalapril were, 7.16 and 6.36 QALYs, respectively, an increase of 0.79 QALYs (similar to QALYs Gaziano 2016 and ICER 2016 model). Applying the half-cycle correction, the discounted QALYs for Sacubitril/Valsartan and Enalapril were, 7.28 and 6.39 QALYs, respectively, an increase of 0.88 QALYs. Half-cycle increased the estimates for incremental QALYs by 11%.
CONCLUSIONS:
For products with long-term incremental gains, half-cycle correction might potentially capture more treatment benefits. Case study of Sacubitril/Valsartan vs Enalapril Heart Failure with Reduced Ejection Fraction shows near 11% impact of incremental QALYs.
