The correlation between sleep duration and heart failure has been established, yet the majority of studies are observational in nature, rendering causal inference difficult due to confounding variables.

To explore the causal relationship between both inadequate and excessive sleep durations and heart failure using two-sample Mendelian randomization (MR) .

The research data was derived from the genome-wide association study (GWAS) summary database, wherein inadequate sleep duration consisted of 106 192 samples and excessive sleep duration consisted of 34 184 samples. Appropriate single nucleotide polymorphisms (SNPs) were selected as instrumental variables, and two-sample Mendelian randomization analyses were conducted using inverse variance weighted (IVW), weighted median, Weighted mode and MR-Egger regression to evaluate the causal relationship between sleep duration and heart failure, as measured by the odds ratio. Sensitivity analyses were performed using heterogeneity testing, horizontal pleiotropic test, and leave-one-out analysis.

23 SNPs were identified as being associated with inadequate sleep duration, while 5 SNPs were associated with exessive sleep duration. The IVW analysis revealed that inadequate sleep duration was a risk factor for heart failure [OR (95%CI) =2.347 (1.209-4.555), P=0.012]. After removal of SNPs with multiple testing correction, demonstrated the robustness of MR results.

There is a positive causal relationship between short sleep duration and heart failure, that is, short sleep duration increases the risk of heart failure.