Association between magnesium oxide use and readmission risk in patients with heart failure and constipation.

Background: Constipation is frequently observed in patients with chronic heart failure and has been linked to a heightened risk of adverse heart failure outcomes. Although laxatives are commonly prescribed, the optimal choice for individuals with heart failure remains uncertain. We evaluated the association between magnesium oxide use and heart failure prognosis in patients with chronic heart failure.

Methods: A retrospective observational study was conducted on patients admitted to our hospital for heart failure between January 2020 and December 2023 who were continued to be prescribed the same laxatives after discharge. Patients who received magnesium oxide for regular use were categorized into the magnesium oxide group, while all other patients comprised the nonmagnesium oxide group. The primary endpoints were heart failure-related readmission and all-cause mortality, while the secondary endpoint was a composite of both. Propensity scores were calculated based on baseline patient characteristics and used to perform 1:1 nearest-neighbor matching.

Results: During the study period, 171 outpatients with heart failure were prescribed laxatives after hospital discharge, with 74 patients included in the magnesium oxide group. Using propensity score matching, a cohort of 41 matched pairs was established. After matching, the analysis showed that the hazard ratio (HR) for first readmission within 360 d was 0.33 (95% confidence interval [CI]: 0.10-0.92, p = 0.035). Additionally, the combined risk of first readmission and all-cause mortality was associated with an HR of 0.30 (95% CI: 0.11-0.82, p = 0.019).

Conclusion: Magnesium oxide was strongly associated with a lower risk of readmission and/or death in patients with heart failure who were prescribed laxatives.

Trial registration: N/A. Cases were registered retrospectively.