High‐Normal Serum Potassium, Calcium, and Magnesium Levels Are Associated With Decreased Risks of Adverse Outcomes After Ischemic Stroke

Background High serum potassium, calcium, and magnesium levels have been reported to be associated with decreased risks of ischemic stroke, whereas their prognostic values in ischemic stroke remain unclear. We aimed to prospectively explore the associations of serum potassium, calcium, and magnesium levels with the prognosis of ischemic stroke. Methods We measured serum potassium, calcium, and magnesium levels at baseline among 5469 patients with ischemic stroke from the Minhang Stroke Cohort study. The primary outcome was the composite outcome of death and major disability (modified Rankin Scale score ≥3) at 3 months after ischemic stroke. Secondary outcomes included major disability, death, and the ordered 7‐level categorical score of the modified Rankin Scale. Results During 3‐month follow‐up, 1834 patients developed the primary outcome. After multivariate adjustment, the adjusted odds ratios of primary outcome for the highest versus the lowest quartile were 0.79 (95% CI, 0.68–0.93; P trend =0.007) for potassium, 0.69 (95% CI, 0.58–0.82; P trend <0.001) for calcium, and 0.83 (95% CI, 0.70–0.99; P trend =0.015) for magnesium. Multivariable‐adjusted restricted cubic spline analyses showed linear dose–response relationships of serum potassium, calcium, and magnesium with the risk of primary outcome (all P for linearity<0.05). Conclusions High‐normal serum potassium, calcium, and magnesium levels were associated with decreased risks of adverse outcomes at 3 months after ischemic stroke, suggesting that serum potassium, calcium, and magnesium might be valuable prognostic biomarkers for ischemic stroke.