Cost-effectiveness of folic acid therapy for primary prevention of stroke in patients with hypertension

Abstract

Background: For hypertensive patients without a history of stroke or myocardial infarction (MI), the China Stroke Primary Prevention Trial (CSPPT) demonstrated that treatment with enalapril-folic acid reduced the risk of primary stroke compared with enalapril alone. Whether folic acid therapy is an affordable and beneficial treatment strategy for the primary prevention of stroke in hypertensive patients from the Chinese healthcare sector perspective has not been thoroughly explored. Methods: We performed a cost-effectiveness analysis alongside the CSPPT, which randomized 20,702 hypertensive patients. A patient-level microsimulation model based on the 4.5-year period of in-trial data was used to estimate costs, life years, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) for enalapril-folic acid vs. enalapril over a lifetime horizon from the payer perspective. Results: During the in-trial follow-up period, patients receiving enalapril-folic acid gained an average of 0.016 QALYs related primarily to reductions in stroke, and the incremental cost was $706.03 (4553.92 RMB). Over a lifetime horizon, enalapril-folic acid treatment was projected to increase quality-adjusted life years by 0.06 QALYs or 0.03 life-year relative to enalapril alone at an incremental cost of $1633.84 (10,538.27 RMB), resulting in an ICER for enalapril-folic acid compared with enalapril alone of $26,066.13 (168,126.54 RMB) per QALY gained and $61,770.73 (398,421.21 RMB) per life-year gained, respectively. A probabilistic sensitivity analysis demonstrated that enalapril-folic acid compared with enalapril would be economically attractive in 74.5% of simulations at a threshold of $37,663 (242,9281 RMB) per QALY (3x current Chinese per capita GDP). Several high-risk subgroups had highly favorable ICERs < $12,554 (80,976 RMB) per QALY (1x GDP). Conclusions: For both in-trial and over a lifetime, it appears that enalapril-folic acid is a clinically and economically attractive medication compared with enalapril alone. Adding folic acid to enalapril may be a cost-effective strategy for the prevention of primary stroke in hypertensive patients from the Chinese health system perspective.