Supplementation with Folic Acid and Cardiovascular Outcomes in End-Stage Kidney Disease: A Multi-Institution Cohort Study

Background: Folate is a water-soluble vitamin and is essential for maintaining cell functions. Dialysis removes folate, and folate deficiency is reported in patients with end-stage kidney disease (ESKD). However, there is no consensus as to the appropriate dosage of folate supplements and their advantages and disadvantages for patients with ESKD. Methods: This study was based on the electronic medical records of the Chang Gung Research Database (CGRD) of the Chang Gung Medical Foundation. We included patients who were diagnosed with ESKD, initiated hemodialysis, and were given folic acid supplements at any point from 1 January 2001 to 31 December 2019. The patients were divided into weekly and daily folic acid supplementation groups. We reduced the effects of confounding through the inverse probability of treatment weighting based on the propensity score. Results: We identified 2081 and 954 newly diagnosed patients with ESKD, who received daily and weekly folic acid supplements. The mean follow-up time was 5.8 years, and the event rates of arteriovenous access thrombosis were 17.0% and 23.6% in the daily and weekly folic acid supplementation groups (sub-distribution hazard ratio = 0.69, 95% confidence interval = 0.61 to 0.77), respectively. Neither group significantly differed in the occurrence of other clinical events, such as major cardiovascular cardiac events (e.g., myocardial infarction and ischemic stroke), all-cause mortality, cardiovascular death, infection death, malignancy, and adverse effects. Conclusion: a daily 5 mg folic acid supplementation might result in a lower event rate of arteriovenous access thrombosis in patients with ESKD than weekly folic acid supplementation. Further prospective studies are warranted to explore the preventive effect of folate on thrombosis.