Estimated Stroke-Free Survival of Folic Acid Therapy for Hypertensive Adults: Projection Based on the CSPPT

The CSPPT (China Stroke Primary Prevention Trial) demonstrated a significant risk reduction of first stroke in hypertensive patients treated with enalapril plus folic acid compared with those with enalapril alone, but the lifetime stroke-free survival associated with the treatment is unknown. By establishing adjusted models for competing risks and an age-based time scale using data from 19 053 participants of the CSPPT, we estimated lifetime incremental stroke-free survival for enalapril-folic acid versus enalapril alone. Compared with enalapril alone, the enalapril plus folic acid treatment projected a mean lifetime stroke-free survival gain of 1.75 months, with an interquartile range from 0.73 to 2.39 months and the maximum gain up to 12.95 months. Subgroup analyses showed greater gain in stroke-free survival in younger, male patients, those with lower baseline folate levels, higher baseline systolic blood pressure, higher baseline total cholesterol and blood glucose, and with MTHFR (methylenetetrahydrofolate reductase) C677T CT or TT genotype. Overall, besides significant benefit in certain subgroups, enalapril plus folic acid treatment for hypertensive patients is associated with a modest gain in lifetime stroke-free survival, compared with enalapril alone.