Renal function, serum magnesium levels and mortality in COVID-19 patients with type 2 diabetes

Patients with type 2 diabetes (T2D) and Latin American subjects in particular are at an increased risk of developing severe COVID-19 and mortality. Altered renal function and lower magnesium levels have been reported to play important roles in the pathophysiology of T2D. The aim of the study was to investigate the relationship between renal function, serum magnesium levels and mortality in T2D patients with COVID-19. In this retrospective study, we characterized 118 T2D and non-diabetic subjects hospitalized with COVID-19. Patients were clinically characterized and electrolyte, renal function and inflammatory markers were evaluated. Patients were grouped according to their estimated glomerular filtration rate (eGFR <60 mL/min per 1.73 m²). T2D patients had lower eGFR and serum magnesium levels when compared to non-diabetics (59.7 ± 32.8 vs. 78.4 ± 33.8 mL/min per 1.73 m², P = 0.008 and 1.9 ± 0.3 vs. 2.1 ± 0.3 mEq/L, P = 0.012). Survival was worse in T2D patients with eGFR levels less than 60 mL/min per 1.73 m² as estimated by Kaplan-Meier analyses (log-rank test <0.0001). The Cox model for T2D patients showed that eGFR (HR 0.970, 95% CI 0.949 to 0.991, P = 0.005) and magnesium (HR 8.025, 95% CI 1.226 to 52.512, P = 0.030) were associated with significantly increased risk of death. Reduced eGFR and magnesium levels were associated with increased mortality in our population. These results suggest that early assessment of kidney function, including magnesium levels, may assist in developing effective treatment strategies to reduce morbidity and mortality among Latin American COVID-19 patients with T2D.