The Correlation of Hypokalemia and Hypomagnesemia in ICU Patients: A Cross Sectional Study

AIM & OBJECTIVES: The study aims to examine the correlation between hypomagnesemia and hypokalemia, determine if there is a critical potassium level where magnesium deficiency is more likely, and analyze the severity of hypokalemia in ICU patients with hypomagnesemia. MATERIALS AND METHODS: This cross-sectional descriptive study was conducted in the ICU of Jaslok Hospital from October 2022 to April 2024. Adult ICU patients (aged 18 years and older) with potassium levels (serum potassium ≤ 3.5 mEq/L) were included and serum magnesium levels were sent. Patients on antacids or magnesium supplements were excluded. A total of 91 patients were selected using systematic random sampling, based on a prior study showing 62% hypomagnesemia in hypokalemic patients. Data, including demographics and lab results, were extracted from electronic medical records. Statistical analyses included chi-square, Pearson correlation, and receiver operating characteristic (ROC) curve analysis. RESULTS: Hypomagnesemia prevalence was 64.84%. ROC analysis for potassium as a predictor of hypomagnesemia showed an area under the curve (AUC) of 0.652, with a potassium cut off of ≤3.1 mEq/L, sensitivity of 52.54%, and specificity of 75%. The positive predictive value (PPV) was 79.5%, and the negative predictive value (NPV) was 46.2%. The Pearson correlation coefficient between potassium and magnesium was 0.463 (p < 0.0001), indicating a moderately positive correlation and statistically significant relation between magnesium and potassium. CONCLUSION: This study shows a significant association between hypomagnesemia and hypokalemia in ICU patients, with potassium ≤3.1 mEq/L as a critical marker for predicting hypomagnesemia. These findings emphasize the need for careful electrolyte monitoring in critically ill patients.