Incidence of and factors associated with hypophosphatemia in children and adolescents receiving cancer treatment: a single-center, retrospective study

The aim of this study was to determine the incidence of hypophosphatemia and identify factors associated with high-risk hypophosphatemia in children and adolescents with cancer. Patients aged 0-18 years who developed hypophosphatemia during treatment for cancer in our hospital between January 2021 and March 2023 were enrolled. Hypophosphatemia was defined as a serum phosphorus level < 2.5 mg/dL. The high-risk group for symptomatic hypophosphatemia was defined as patients with a serum phosphorus level of 1.5-1.9 mg/dL lasting for 2 weeks or more and patients with a serum phosphorus level < 1.5 mg/dL. During the study period, 48 of 253 (19%) patients developed a total of 108 episodes of hypophosphatemia. Symptomatic episodes were more frequent in the high-risk group (n = 31; 84% vs. 39%). Elevated total bilirubin level (> 0.50 mg/dL) (adjusted odds ratio (OR), 3.60; 95% confidence interval (CI), 1.37-9.48) and stem cell transplantation (adjusted OR, 4.83; 95% CI, 1.69-13.81) were found to be potential baseline predictors of high-risk hypophosphatemia in the logistic regression model. Fasting, diarrhea, and vomiting after initiation of treatment were also associated with the development of high-risk hypophosphatemia. Conclusions: The incidence of hypophosphatemia was relatively high in children and adolescents receiving treatment for cancer. The results suggest that baseline characteristics and therapy-related toxicities may be associated with the development of high-risk hypophosphatemia.