Serum Phosphorus and Hypophosphatemia During Therapy of Diabetic Ketoacidosis in Children: Single-Center, Retrospective Cohort 2016-2022.

Objectives: To assess factors associated with serum phosphorus (P) and hypophosphatemia in children with type 1 diabetes mellitus (T1DM) treated for diabetic ketoacidosis (DKA).

Design: Retrospective cohort.

Setting: Community-based PICU in a university-affiliated hospital.

Patients: Patients 1-20 years old with T1DM hospitalized for DKA from July 1, 2016, to July 31, 2022.

Interventions: None.

Measurements and main results: We collected age, sex, duration of T1DM, conscious state at presentation, and most recent glycohemoglobin level. P was tested initially and then every 4 hours. Probability of hypophosphatemia and time to hypophosphatemia and hospital length of stay (LOS) were analyzed via binomial and linear mixed-effects regression analyses, respectively. A total of 852 DKA episodes occurred in 365 patients (46.3% female, median age 14.7 yr), of which 158 (18.5%) episodes were new-onset T1DM. Hypophosphatemia developed during 656 of 852 (77%) episodes, including 49 of 852 (5.8%) episodes of severe hypophosphatemia with median (interquartile range) onset 8.0 hours (4.7-11.9 hr) and 12.0 hours (8.1-17.6 hr), respectively, following initiation of therapy. Higher glycohemoglobin was associated with greater odds of hypophosphatemia (odds ratio [OR], 1.22; p < 0.001). However, lower odds of hypophosphatemia were associated with older age (OR, 0.89; p < 0.01), male (OR, 0.11; p = 0.01), longer T1DM duration (OR, 0.87; p < 0.001), and having initial normal conscious state (OR, 0.18; p < 0.01). Older age (3.0%/yr; p = 0.02), T1DM duration (4.1%/yr; p = 0.01), and initial serum P (23.4%/mg/dL; p < 0.001) were associated with later hypophosphatemia. LOS was shorter with increased T1DM duration (3.6%/yr; p < 0.001) and normal conscious state (33.1% shorter; p < 0.001), but longer with increasing glycohemoglobin (4.0%; p < 0.001). All patients survived with normal neurologic function.

Conclusions: Higher glycohemoglobin was associated with greater odds of hypophosphatemia and longer LOS. Older male, longer duration of T1DM, and conscious at admission were factors associated with lower odds of developing hypophosphatemia and with later onset when it occurred. Hypophosphatemia was associated with longer LOS.