Phosphate abnormalities and outcomes among admissions to the intensive care unit: A retrospective multicentre cohort study

Purpose: We investigated the effect of serum phosphate abnormalities at intensive care unit (ICU) admission on risk of death and length of stay in critically ill patients. Materials and methods: A retrospective cohort of patients admitted to three adult ICUs in Queensland, Australia from April 2014 to 2019 was studied. Hypophosphataemia, normophosphataemia and hyperphosphataemia were defined as serum phosphate level of < 0.8, 0.8-1.5 and > 1.5 mmol/L respectively. Univariable and logistic regression analyses were performed to investigate the association between the phosphate groups and the risk of death. Measurements and main results: We included 13,155 patients in the analysis, of which 1424 (10.8%) patients had hypophosphataemia and 2544 (19.3%) hyperphosphataemia. The mean admission phosphate level was 1.25 (SD, +/- 0.43) mmol/L. Both hypophosphatemia (OR 1.29; 95% CI, 1.02-1.64; p = 0.034) and hyperphosphataemia (OR 1.39;95% CI, 1.15-1.68; p = 0.001) at admission were independently associated with increased risk of death after adjusting for covariables using logistic regression analysis. Conclusion: Hypophosphatemia and hyperphosphatemia were both independently associated with an increased case fatality rate and ICU length of stay in a large multicentre ICU cohort. (c) 2021 Published by Elsevier Inc.