What is the most common cause of hypophosphatemia in hospitalized patients?

In the context of hospitalized patients, the most common cause of hypophosphatemia is indeed related to continuous glucose infusion. When patients receive a high amount of carbohydrates, such as through intravenous glucose infusion, insulin is stimulated to promote glucose uptake into cells. This process not only lowers blood glucose levels but also drives phosphate into the cells as part of the metabolic process, increasing the intracellular demand for phosphate. This can lead to a decrease in serum phosphate levels, resulting in hypophosphatemia.

Continual glucose intake, especially in high amounts, can cause what is known as refeeding syndrome in susceptible individuals, which further complicates the phosphate metabolism. Consequently, monitoring phosphate levels in patients receiving such treatments is crucial to prevent hypophosphatemia and its associated complications, such as muscle weakness, respiratory failure, and hemolysis.

Other causes of hypophosphatemia—such as malnutrition, acute kidney injury, or excessive phosphate intake—can also occur but are not as prevalent in the setting of hospitalized patients, particularly when dealing with those receiving intravenous nutrition or high doses of glucose. Therefore, the metabolic shifts caused by insulin release during continuous glucose infusion make it the most common cause of hypophosphatemia in this population.