BACKGROUND: Despite having a pivotal role in numerous physiologic functions, magnesium disorders are rarely considered in clinical practice. This study aimed to explore the burden, predictors, and outcomes associated with magnesium imbalances among critically ill patients admitted to critical care settings with diarrheal disease. METHODS: A retrospective chart analysis was done among critically ill patients with diarrhea aged more than 18 years admitted to the Intensive Care Unit (ICU) of a specialized hospital who had their serum magnesium measured. Data were extracted from an electronic health record system. Serum magnesium levels were measured upon ICU admission. Multivariate multinomial logistic regression analysis was done to find out the associations with clinical variables. RESULTS: There was a higher incidence of hypomagnesemia (34%) than hypermagnesia (5.9%). On multivariate analysis, there were independent associations of hypomagnesemia with sepsis (mOR=6.25, 95% CI: 3.61 to 10.81, p <
0.002), H/O regular medicine intake prior admission (mOR=1.94, 95% CI: 1.18 to 3.18, p = 0.01). On the other hand, hypermagnesemia was independently associated with dehydration (mOR=4.78, p = 0.003, 95% CI: 1.6 to 14.3). Comparing with other electrolyte disorders, hypocalcemia (p <
0.002) was associated with hypomagnesemia. Hypermagnesemia was associated with hypochloremia (p = 0.017), metabolic acidosis (p = 0.014), and hypercalcemia (p = 0.002). CONCLUSION: The high occurrence of dysmagnesemia in our study highlights the need to closely monitor magnesium in critically ill ICU patients, particularly in resource limited settings. This could help prevent serious complications related to magnesium imbalances. Intensivists should remain alert to magnesium disturbances and conduct thorough patient evaluations.