Hypocalcemia in critically ill patients in a teritiary care hospital

Background: Hypocalcemia is frequently encountered in critically ill hospitalized patients. The most accurate measure of true hypocalcemia is ionized calcium level. This study was done to ascertain the frequency, risk factors and outcome in critically ill patients admitted to the ICU with hypocalcemia.
Materials and Methods: This was a single- centre, retrospective, observational study. The population was derived patients admitted to the ICU, the postoperative critical care unit or the high dependency unit at SMHS Hospital were eligible for inclusion. For the purpose of the present study, hypocalcemia was defined as ionized Calcium (iCa++) level less than 1.16 mmol/L. The patients were divided into two groups: hypocalcemic (iCa++ level
<1.16mmol/l) and normocalcemic (iCa++ level between 1.16–1.33 mmol/L).
Both these groups were compared using the log-rank test, and the results are presented as Kaplan-Meier curves.
Results: Of the 170 patients, The mean age of patients admitted was 59.5yrs, with a median of 61yrs. Out of these, 47% were females and 53% male and the mean APACHE score of 19(IQR 14-24). We measured total calcium, albumin corrected calcium and ionised calcium in our study, after an initial assessment. The mean total calcium levels were 8.8g/dl and the mean corrected calcium (corrected for hypoalbuminemia) level 9.2mg/dl. Out of these 47% patients were hypocalcemic (S Ca <8.8mg/dl), 50.1%patients were normocalcemic and 5 patients (2.9%) were hypercalcemic which were excluded from further analysis. Further, the mean admission iCa was 4.2mg/dL (SD) and 88.2% patients were classified as hypocalcemic (iCa <4.7mg/dl). Out of the 85 patients who were normocalcemic on serum calcium measurements 65(76.5%) were hypocalcemic when ionised calcium was measured. Patients with low serum ionized Ca++ values had longer ICU stay and longer mechanical ventilation days, with a higher mortality rate. Conclusion hypocalcemia is usual finding in critically ill patients, and has an adverse effect on disease severity and outcome and also the hospital stay.