Low Serum Calcium Predicts Higher Stroke Severity: A Hospital-Based Study of Nihss Score Determinantslow Serum Calcium Predicts Higher Stroke Severity: A Hospital-Based Study of Nihss Score Determinants

Background: Ischemic stroke is a leading cause of global mortality and long-term disability, accounting for the majority of all stroke cases. The severity of neurological impairment in acute stroke directly influences clinical outcomes and recovery potential. Recent evidence suggests that systemic calcium dysregulation may contribute to ischemic brain injury. As an accessible and cost-effective laboratory marker, serum calcium has the potential to aid early prognostic assessment in acute stroke. Objective: To assess the association between serum calcium levels and stroke severity, as measured by the NIH Stroke Scale (NIHSS), in patients with acute ischemic stroke. Methods: This cross-sectional study was conducted at the Department of Neurology, Pakistan Institute of Medical Sciences (PIMS), Islamabad, from August 2024 to February 2025. A total of 1201 adult patients (≥18 years) with CT or MRI-confirmed acute ischemic stroke presenting within 24 hours of symptom onset were enrolled. Serum calcium levels and other biochemical parameters were assessed within 12 hours of hospital admission. NIHSS scores were assigned by certified neurologists within 24 hours of presentation. Multivariate linear regression analysis was used to determine the independent association between serum calcium and NIHSS scores, adjusting for age, serum albumin, blood pressure, serum electrolytes, and length of hospital stay. Results: The mean serum calcium level was 8.71 ± 0.54 mg/dL, while the average NIHSS score was 15.27 ± 5.83. Among the cohort, 36% had calcium levels ≤8.5 mg/dL. A significant inverse correlation was found between serum calcium and stroke severity (r = –0.31, p = 0.00047). In multivariate regression, serum calcium remained an independent predictor of NIHSS score (β = –3.3, 95% CI: –5.2 to –1.4, p = 0.001). Conclusion: Lower serum calcium levels are independently associated with greater neurological impairment in acute ischemic stroke, supporting its utility as a prognostic biomarker in clinical practice.