Magnesium Depletion Score and Its Potential as an Indicator of Chronic Magnesium Deficiency in Critically Ill Patients

Chronic latent magnesium (Mg) deficiency is a subclinical chronic depletion of Mg body stores. Although this deficiency contributes significantly to morbidity and mortality in critically ill patients, its diagnosis remains difficult because current clinical practice lacks a simple, rapid, and reliable single measurement to detect its presence. The magnesium depletion score (MgDS) is a recently developed scoring system to aid clinical prediction of chronic Mg deficiency. This clinical parameter is easily calculated from several factors: chronic use of diuretics and proton pump inhibitors, alcohol abuse, and kidney disease. These MgDS factors lead to a negative Mg metabolic balance and eventual Mg depletion, primarily due to urinary wasting. The main goal of this review was to investigate the existing literature on the MgDS and consider its potential clinical usefulness as a preliminary indicator of chronic latent Mg deficiency in the critically ill. We searched PubMed to conduct a narrative literature review on the MgDS and its potential use in critically ill patients. The identified references spanned the period from inception in August 2021 through August 21, 2026. We identified 80 relevant papers reporting statistically significant associations between the MgDS and various chronic diseases. These included 77 observational clinical studies, 28 cohort studies (24 prospective and 4 retrospective), 49 cross-sectional studies, and 1 systematic review and meta-analysis. Basic research articles were not found, and case reports were excluded. Most studies used data from the National Health and Nutrition Examination Survey (NHANES). Strong correlations link the MgDS to increased risk of many health conditions, including cardiovascular (17 studies), respiratory (6 studies), neuropsychiatric (11 studies), metabolic (22 studies), urogenital (11 studies), rheumatic (5 studies), and some immune-mediated and age-related diseases (7 studies). These findings confirm that chronic Mg deficiency can lead to a wide range of clinical consequences, chronic conditions, and adverse events. Since its introduction, the MgDS has proved to be a promising clinical indicator of chronic latent Mg deficiency. However, a literature search did not reveal any clinical studies on the MgDS in critically ill patients. After evaluating the advantages and disadvantages of using the MgDS, the authors believe that combining the MgDS with serum total Mg2+ and ionized Mg2+ levels could provide a valid assessment of Mg2+ status and significantly improve detection of negative Mg2+ balance associated with various acute and chronic diseases in the critically ill. Moreover, incorporating the MgDS as a prognostic indicator into critical care clinical practice would improve risk stratification and patient management, thereby reducing the adverse health effects of chronic Mg2+ deficiency.