JAMA Internal Medicine Author Interviews Magnesium Supplementation and Tachyarrhythmias
Dec 8, 2025
In this enlightening discussion, Robert Golden, a McGill University emergency physician, dives into his research on magnesium supplementation and its impact on tachyarrhythmias. He reveals the surprising lack of evidence to support routine magnesium use in preventing these heart rhythm issues. Alongside him, Jason H. Wasfy, a Harvard cardiologist, highlights the strengths and limitations of observational studies versus randomized trials. Together, they explore the implications for clinical practice and propose future research directions.
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No Clear Benefit Near Reference Cutoffs
- Routine magnesium repletion for values just outside reference ranges showed no clear reduction in tachyarrhythmias.
- Confidence intervals were wide, so large effects cannot be fully excluded but large benefits are unlikely.
Using Cutoffs As Natural Experiments
- Regression discontinuity exploits treatment cutoffs to compare nearly identical patients on either side of a threshold.
- This method can address unmeasured confounding better than conventional observational approaches.
Treatment Often Mirrors Severity
- Observational data often confounds treatment with severity because clinicians give interventions to sicker patients.
- This makes naive comparisons misleading unless methods account for unmeasured confounding.