Hypomagnesemia as a prognostic marker of ischemic stroke

Background: Hypomagnesemia is associated with stroke severity and increased in-hospital mortality in patients with acute ischemic stroke. This study aimed to assess whether serum magnesium concentration could predict functional outcomes of patients with acute ischemic stroke. Methods: A total of 1,006 patients with acute ischemic stroke were analyzed. A serum magnesium level <1.6 mEq/L was defined as hypomagnesemia. Poor functional outcome was defined as a 3-month modified Rankin Scale (mRS) score ≥4. Multivariate logistic regression models were used to determine the effect of hypomagnesemia on the prognosis of ischemic stroke. Furthermore, patients were grouped according to severity and type of stroke. Within each group, subgroup analyses and interaction analyses were performed to determine whether the effect of hypomagnesemia on functional outcomes was still valid under different clinical conditions. Results: The adjusted odds ratio (OR) for poor 3-month mRS in patients with hypomagnesemia was 2.15 (95% confidence interval [CI], 1.16–3.98; P =0.015). Hypomagnesemia was significantly associated with poor 3-month functional outcomes in patients with minor stroke (Initial National Institutes of Health Stroke Scale [NIHSS] score <5: adjusted OR, 4.20; 95% CI, 1.67–10.59; P =0.002). A significant interaction ( P =0.047) was also observed between hypomagnesemia and the severity of the initial NIHSS. Although there was no significant interaction ( P =0.053), hypomagnesemia was significantly associated with poor functional outcomes in the cardioembolic stroke group (adjusted OR, 3.41; 95% CI, 1.24–9.41; P =0.018). Conclusion: Hypomagnesemia was a strong prognostic marker of poor functional outcome in certain subgroups, especially in patients with mild stroke severity and cardioembolic stroke.