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.