Hypomagnesemia and 30-day mortality in the emergency department: A large-scale propensity-matched analysis

Am J Emerg Med. 2026 Sep 8;110:349-354. doi: 10.1016/j.ajem.2026.09.016. Online ahead of print.

ABSTRACT

BACKGROUND: The incidence and mortality associated with hypomagnesemia (HM) in emergency department (ED) patients is poorly described. We explore the epidemiology and prognosis of HM (Mg + ≤1.6 mg/dL) in ED patients using a national database.

METHODS: This study utilized data from the TriNetX Research Network, from 110 participating healthcare organizations. We included patients aged ≥18 years who presented to the ED between 1/1/25 and 12/31/25. Patients were dichotomized into those with HM (Mg + ≤1.6 mg/dL) and normal controls (Mg + 1.7-2.2 mg/dL). To reduce confounding, 1:1 propensity score matching (PSM) was performed based on age, sex, race, ethnicity, and common comorbidities. The primary outcome was death within 30 days of the index ED visit.

RESULTS: Of 1,246,550 eligible ED patients, 164,663 (13.2%) had HM. HM patients were older than controls (mean 59.1 vs. 55.9 years) and more likely to be female (57.2% vs. 55.6%). HM was significantly more common in patients with hypertension, diabetes, AKI/CKD, alcohol use disorder, malnutrition, and chronic diuretic use (all p < 0.001). After PSM for demographic and clinical variables, the risk of 30-day mortality remained more than 70% higher in those with HM (3.2% vs. 1.9%, OR 1.7, 95% CI 1.7-1.8).

CONCLUSIONS: This real-world, observational study found that ED patients with hypertension, diabetes, AKI/CKD, alcoholic use disorder, malnutrition, and chronic diuretic use were more likely to have HM. After PSM, hypomagnesemia was associated with greater 30-day mortality, with an absolute increase of 1.3% or relative increase of 70%.

PMID:42748530 | DOI:10.1016/j.ajem.2026.09.016