Acute Decrease in Serum Magnesium Level after Ischemic Stroke May Not Predict Decrease in Neurologic Function James E. Siegler, MD,* Amelia K. Boehme, MSPH,†‡ Karen C. Albright, DO, MPH,†‡xjj Sami Bdeir, MD,*{ Anoop K. Kar, BA,* Leann Myers, PhD,# T. Mark Beasley, PhD,** and Sheryl Martin-Schild, MD, PhD* Background: Higher serum levels of magnesium (Mg(21)) may contribute to im- proved outcome following ischemic stroke, and this may be related to vessel recanali- zation. Patients with low or normal serum magnesium levels during the acute phase of ischemic stroke may be more susceptible to neurologic deterioration (ND) and worse outcomes. Methods: All patients who presented to our center within 48 hours of acute ischemic stroke (July 2008 to December 2010) were retrospectively identified. Patient demographics, laboratory values, and multiple outcome measures, including ND, were compared across admission serum Mg(21) groups and change in Mg(21) from baseline to 24-hour groups. Results: Three hundred thirteen patients met inclu- sion criteria (mean age: 64.8 years, 42.2% female, 64.0% black). Mg(21) groups at base- line were not predictive of poor functional outcome, death, or discharge disposition. Patients whose serum Mg(21) decreased during the first 24 hours of admission were also not at greater odds of ND or poor outcome measures compared with patients with unchanging or increasing Mg(21) levels. Conclusions: Our results suggest that patients who have low Mg(21) at baseline or a reduction in Mg(21) 24 hours after ad- mission are not at a higher risk of experiencing ND or poor short-term outcome. On- going prospective interventional trials will determine if hyperacute aggressive magnesium replacement affords neuroprotection in stroke. Key Words: Stroke— ischemia—magnesium—neurologic deterioration—neuroprotection. Ó 2013 by National Stroke Association Background Magnesium (Mg(21)) ions are known to block gluta- matergic N-methyl-D-aspartate receptors in the central nervous system during instances of glutamate neurotox- icity 1 such as acute ischemic stroke. 2 Low Mg(21) at the time of stroke may accelerate penumbral compromise and result in more severe stroke presentations 3 or early From the *Stroke Program, Department of Neurology, Tulane Uni- versity Hospital, New Orleans, Louisiana; †Department of Epidemiol- ogy, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama; ‡Comprehensive Stroke Center, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama; xHealth Services and Outcomes Research Center for Out- come and Effectiveness Research and Education; jjCenter of Excellence in Comparative Effectiveness Research for Eliminating Disparities Minority Health and Health Disparities Research Center; {Damascus University, College of Medicine, Damascus Governornate, Syria; #Department of Biostatistics and Bioinformatics, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA; and **Department of Biostatistics, School of Public Health, University of Alabama, Birmingham, AL. Received February 18, 2013; revision received April 17, 2013; accepted May 26, 2013. Disclosures: The project described was supported by award num- bers 5 T32 HS013852-10 from the Agency for Healthcare Research and Quality, 3 P60 MD000502-08S1 from the National Institute on Mi- nority Health and Health Disparities and the National Institutes of Health, and 13PRE13830003 from the American Heart Association (AHA). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Agency for Healthcare Research and Quality, AHA, or the National Institutes of Health. J.E.S. received a student scholarship in stroke and cerebrovas- cular disease through the AHA for the purpose of this study. Address correspondence to Sheryl Martin-Schild, MD, PhD, Stroke Program at Tulane University Hospital, Department of Psychiatry and Neurology, 1415 Tulane Avenue, New Orleans, LA 70112. E-mail: smartin2@tulane.edu. 1052-3057/$ - see front matter Ó 2013 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2013.05.030 Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2013: pp 1-6 1