A prospective, randomized, double-blind, placebo-controlled, multicenter study of thiamin plus folic acid in the treatment of cognitive impairment in patients undergoing maintenance hemodialysis.

This prospective, randomized, double-blind, placebo-controlled trial investigated the efficacy and safety of thiamin and folic acid for cognitive impairment in maintenance hemodialysis (MHD) patients. A total of 215 MHD patients aged 18-75 with cognitive impairment were randomized to receive either oral thiamin (90 mg/day) plus folic acid (30 mg/day) or a placebo for 96 weeks. The primary endpoint was the change in the Alzheimer's Disease Assessment Scale-Cognitive section (ADAS-Cog) score. After 96 weeks, the treatment group showed a significant improvement in ADAS-Cog scores (from 21.25 ± 9.2 to 15.07 ± 8.38, p < 0.001), whereas the placebo group showed a non‑significant improvement (from 24.53 ± 11.01 to 26.53 ± 14.43, p = 0.077). The treatment group also demonstrated significantly increased blood levels of thiamin (from 5.59 ± 0.95 to 18.21 ± 3.91 ng/mL) and folate (from 12.37 ± 4.62 to 63.33 ± 16.02 ng/mL), and a reduction in homocysteine levels (from 4709.06 ± 353.15 to 2962.68 ± 158.87 ng/mL, p < 0.001), with no significant changes in the placebo group. While mortality was similar between the two groups (12.1% vs. 12.0%, p = 0.978), the incidence of adverse events was significantly lower in the treatment group (31.8% vs. 62.0%, p = 0.0017), particularly cardiovascular and cerebrovascular events (13.1% vs. 25.9%, p = 0.001). The study concludes that combined thiamin and folic acid supplementation improves cognitive function in MHD patients with a favorable safety profile.