Feeding-associated hypophosphatemia in critically ill patients. A multicentre, observational study

Feeding-associated hypophosphataemia in critically ill patients is a well-recognised phenomenon that has been associated with adverse outcomes. However, the research has been limited by various definitions and small sample sizes.

A multicentre retrospective cohort study of critically ill patients from six intensive care units in Queensland, Australia. Feeding-associated hypophosphataemia was defined as a decrease of >0.16 mmol.L^-1 and a phosphate nadir of 0.80 ≤ mmol.L^-1 within 24 h of nutrition commencement.

A total of 10,672 patients, with a mean age of 56 ± 17 years and a mean Acute Physiology and Chronic Health Evaluation III score of 63 ± 27, were included. On the day of nutrition commencement, 7801 (73 %) patients were invasively ventilated, and 7053 (66 %) were on vasopressor support. Within 24 h of nutrition, 1298 (13 %) developed moderate to severe feeding-associated hypophosphataemia. Crude hospital mortality was higher in the moderate/severe feeding-associated hypophosphatemia group compared to the control group (18 % vs. 14 %, p < 0.001). Caloric quantity (aOR = 1.06; 95 %CI [1.02, 1.10]), feeding commenced within 48 h of admission (aOR = 1.56; 95 %CI [1.28, 1.91]) and receiving insulin on the day of feeding start (aOR = 1.22; 95 %CI [1.07, 1.40]) were independently associated with developing feeding-associated hypophosphataemia. After adjustment for confounders, moderate-severe feeding-associated hypophosphataemia was independently associated with an increased risk of 30-day hospital mortality (HR = 1.30; 95 %CI [1.08 to 1.56]).

In a large group of critically ill patients, almost one in seven patients experienced moderate to severe hypophosphatemia after starting to consume calories. The dose of caloric intake and early nutrition initiation were linked to its development. Additionally, moderate to severe hypophosphatemia was independently associated with a higher risk of 30-day hospital mortality.