Magnesium supplementation does not reduce risk of tachyarrhythmias

Magnesium supplementation to treat hypomagnesemia does not appear to have any beneficial effect on the risk of tachyarrhythmias, according to a study.

The study involved intensive care unit (ICU) patients undergoing serum magnesium testing at 93 ICUs across the US and Europe. The primary outcome was ventricular or supraventricular tachyarrhythmia in the 24 h after magnesium testing. The occurrence of hypotension or death was the secondary outcome.

Researchers performed a fuzzy regression discontinuity design, wherein study outcomes were compared between patients just either side of the eligibility cutoff for magnesium supplementation. This comparison was performed across a range of treatment cutoffs in current use, ranging from 1.6 to 2 mg/dL.

The analysis included 478,901 24-h treatment windows from 171,727 ICU patients (mean age 63 years, 42.4 percent female). Magnesium supplementation had no significant effect on the occurrence of tachyarrhythmia, with a risk difference of 0.1 percent (95 percent confidence interval [CI], −4.2 to 6.9). This finding was consistent across all the cutoff levels evaluated.

Similarly, there was no evidence of an association between magnesium supplementation and the occurrence of hypotension (risk difference, 1.2 percent, 95 percent CI, −0.9 to 17.7) or death (risk difference, 1.4 percent, 95 percent CI, −0.6 to 5.3).