Thiamine plays a crucial role for normal cardiac function, as severe vitamin B1 (thiamine) deficiency leads to congestive heart failure. Thus, patients undergoing diuretic treatment might have compromised heart function. Several small-scale studies were conducted with conflicting results".

The aim of this study was to determine the effects of thiamine supplementation on cardiac function among patients with heart failure with reduced ejection fraction receiving optimal medical therapy versus optimum medical therapy alone.

This was a meta-analysis of randomized, double-blind, placebo-controlled trials

Studies for inclusion were searched using PubMed, Google Scholar, Cochrane, EMBASE, and other databases. Gray literature was also explored. Review Manager version 5.3 was used to analyze data. The mean difference and 95% confidence interval were estimated using random-effects model. χ2 and I 2 were computed to assess heterogeneity.

After the analysis of the combined effects of five studies with 218 subjects, the pooled results showed no significant effect on the left ventricular ejection fraction in heart failure patients when given thiamine supplementation with a P value of 0.04.

Based on this limited group of studies, there is insufficient information to suggest that thiamine supplementation has a positive effect on left ventricular ejection fraction in heart failure patients. Further large-scale clinical trials are needed to determine the optimum dose, duration, and route of thiamine in patients with heart failure.