Association between serum magnesium levels and severity of acute exacerbations in COPD: a cross-sectional study

Abstract Background Magnesium has an established role in respiratory physiology, but its relationship with the severity of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains unclear. This study evaluated whether serum magnesium levels are associated with exacerbation severity in hospitalized patients with AECOPD. Methods In this cross-sectional study, 149 patients admitted with AECOPD in 2024 were classified into mild, moderate, or severe groups using predefined clinical and laboratory criteria at admission. Serum magnesium, oxygen saturation, arterial pH, and C-reactive protein (CRP) were measured. Group comparisons, correlation analyses, and ordinal logistic regression were performed. Results Hospital length of stay increased across severity categories ( P = 0.006). Serum magnesium did not differ between mild, moderate, and severe AECOPD ( P = 0.357), and hypomagnesemia was uncommon (7.4%) with no association with severity ( P = 0.873). Magnesium was not correlated with oxygen saturation, arterial pH, or CRP and did not independently predict severity in ordinal logistic regression ( P = 0.960). Conclusion Total serum magnesium does not appear to be a reliable marker of AECOPD severity. More physiologically relevant measures, such as ionized or intracellular magnesium, warrant further investigation.