The prognostic impact of magnesium in acute heart failure is different according to the presence of diabetes mellitus

Catarina Cidade-Rodrigues; Filipe M Cunha; Catarina Elias; Marta Carreira; Isaac Barroso; Paulo Bettencourt; Patrícia Lourenço

doi:10.1097/j.pbj.0000000000000197

The prognostic impact of magnesium in acute heart failure is different according to the presence of diabetes mellitus

Porto Biomed J. 2022 Dec 1;7(6):e197. doi: 10.1097/j.pbj.0000000000000197. eCollection 2022 Nov-Dec.

Authors

Catarina Cidade-Rodrigues¹, Filipe M Cunha¹, Catarina Elias², Marta Carreira², Isaac Barroso³, Paulo Bettencourt^{4

5

6}, Patrícia Lourenço^{2

5

6

7}

Affiliations

¹ Endocrinology Department, Centro Hospitalar do Tâmega e Sousa, Penafiel, Portugal.
² Internal Medicine Department, Centro Hospitalar e Universitário do São João, Porto, Portugal.
³ Clinical Pathology Department, Centro Hospitalar e Universitário do São João, Porto, Portugal.
⁴ Internal Medicine Department, Hospital CUF, Porto, Portugal.
⁵ Faculty of Medicine, University of Porto, Porto, Portugal.
⁶ Cardiovascular R&D Unit (UnIC), Faculty of Medicine, University of Porto, Porto, Portugal.
⁷ Heart Failure Clinic, Internal Medicine Department, Centro Hospitalar e Universitário do São João, Porto, Portugal.

Abstract

Background: Hypermagnesemia predicts mortality in chronic heart failure (HF); however, in acute HF, magnesium does not seem to be outcome-associated. Diabetes mellitus (DM) frequently associates with altered magnesium status. We hypothesized that DM might influence the prognostic impact of magnesium in acute HF.

Methods: This is a retrospective cohort study of hospitalized patients with acute HF. Patients without data on admission serum magnesium were excluded. Follow-up: 1 year from hospital admission. Primary end point: all-cause mortality. Patients were divided according to median serum magnesium (1.64 mEq/L). The Kaplan-Meier survival method was used to determine survival curves according to magnesium levels. The analysis was stratified according to the presence of DM. A multivariable Cox regression analysis was used to study the prognostic impact of magnesium.

Results: We studied 606 patients. The mean age was 76 ± 12 years, 44.1% were male, 50.7% had DM, and 232 (38.3%) died during follow-up. Median magnesium was 1.64 (1.48-1.79) mEq/L. Patients with magnesium ≥1.64 mEq/L had higher 1-year mortality [141 (46.4%) vs 91 (30.1%), P < .001]. After adjustments for age, sex, history of atrial fibrillation, systolic blood pressure, heart rate, ischemic etiology, B-type natriuretic peptide, estimated glomerular filtration rate, alcohol consumption, antihyperglycaemic agents or glycated hemoglobin, admission glycemia, New York Heart Association class IV, and severe left ventricle systolic dysfunction, serum magnesium ≥1.64 mEq/L was associated with higher mortality only in patients with DM: HR 1.89 (95% confidence interval: 1.19-3.00), P = .007, and 1.27 (95% confidence interval: 0.83-1.94) and P = .26 for non-DM patients. The results were similar if magnesium was analyzed as a continuous variable. Per 0.1 mEq/L increase in magnesium levels, patients with DM had 13% increased risk of 1-year mortality.

Conclusions: Higher magnesium levels were associated with worse prognosis only in HF patients with DM.

Keywords: diabetes mellitus; heart failure; magnesium; prognosis.