ALB and Hypocalcemia: Therefore, our study intends to analyze the eICU-CRD v2.0 database in order to 1) identify the prevalence and distribution of the calcium abnormalities of ICU patients in in the United States and 2) investigate the effect of albumin-corrected calcium levels, particularly mild hypocalcemia and hypercalcemia, on the 30-day in-hospital mortality of ICU patients by using a multicenter observational cohort study.