S851 Does Low Magnesium in Veterans Make Esophageal Muscle Cramp?

Introduction: Magnesium (Mg) serves an essential role in neuromuscular coordination, allowing for muscle relaxation by removing calcium back into storage. The role of Mg has been well characterized in neurological disorders. Dysphagia is one of the major presenting symptoms of Mg deficiency in addition to muscle cramps and spasms. However, the role of Mg in dysphagia and spastic esophageal disorders, compared to non-spastic or normal esophageal motility, remains unclear. This is the first study to assess whether a low Mg level is associated with spastic esophageal dysmotility, especially in U.S. veterans who are commonly deficient in Mg. Methods: Retrospective database study was conducted at Edward Hines Jr. Veterans Administration (VA) Hospital for all veterans referred for high-resolution manometry (HRM) from 2013-2024 (Medtronic Manoview ESO 3.3 software). Patterns of dysmotility in veterans with low Mg vs normal Mg were compared. Chronic Mg deficiency was defined as a serum Mg <1.7 mg/dL for >1 year duration. Findings were reported as descriptive statistics. Results: Of 476 total patients, 406 patients were men (85.3%), average age was 62.3 years (23-100), 323 White (67.9%), 112 Black (23.5%), 32 unknown (6.7%), 6 Native American (1.3%), and 3 Asian (0.6%). Sixty-seven (0.14%) with incomplete Mg data were excluded from analysis. The most common indication for HRM was dysphagia for both low Mg and normal Mg groups. Of the remaining 409 patients, 22.7% of patients (93 of 409) had Mg deficiency. Average Mg values were 1.61 (median 1.6, range 1.13-2, standard deviation [SD] 0.17) in low Mg vs 2.12 (median 2.1, range 1.73-3.04, SD 0.16) in normal Mg group. Total number of manometric diagnoses is 110 for the 93 with low Mg and 376 for 316 normal Mg with some patients having overlapping motility diagnoses. Conclusion: This study is the first to raise awareness about the role of Mg in esophageal dysmotility, especially in veterans. Twenty-three percent of veterans at our VA presenting for manometry have hypomagnesemia. Normal Mg group was more likely to have normal manometry results. Esophagogastric junction outflow obstruction was the most common manometric diagnosis irrespective of Mg level. Ineffective esophageal motility (IEM) was the second most common diagnosis among both groups. However, among veterans with IEM in the low Mg group, spastic esophageal contractions like hypertensive upper esophageal sphincter (UES) and diffuse esophageal spams (DES) were more prevalent compared to the normal Mg group (hypertensive UES, 31.25% vs 20%; DES, 6.25% vs 0%). These novel associations between low Mg and esophageal spastic dysmotility warrant further studies.