Measured Serum Osmolality as a Severity Marker of Pediatric Hyperglycemic Crises

Objective: This study aimed to determine whether measured serum osmolality could serve as a reliable marker for assessing the severity and predicting outcomes of pediatric diabetic ketoacidosis (DKA). Methods: We retrospectively analyzed pediatric patients (<19 y) admitted with hyperglycemic crises from 2009 to 2022. Patients were classified into isolated DKA (serum osmolality ≤320 mOsm/kg) and hyperosmolar DKA (>320 mOsm/kg). Clinical characteristics, laboratory results, severity indicators, and outcomes were compared. We further evaluated diagnostic accuracy between measured serum osmolality and calculated effective osmolality, the current marker used by International Society of Pediatric and Adolescent Diabetes guidelines. Results: Among 135 DKA episodes, hyperosmolar DKA (n = 69, 51.1%) presented more severe clinical features than isolated DKA (n = 66, 48.8%), including higher incidences of altered mental status (43.5% vs 12.1%), intensive care unit (ICU) admission (31.9% vs 12.1%), acute kidney injury (AKI; 58.0% vs 12.1%), and prolonged hospitalization (11 vs 8 days). In multivariate logistic regression, higher measured serum osmolality was significantly associated with altered mental status [odds ratio (OR), 1.048; 95% CI, 1.007-1.090], ICU admission (OR, 1.062; 95% CI, 1.016-1.111), AKI (OR, 1.070; 95% CI, 1.027-1.112), and prolonged hospital stay (OR, 1.032; 95% CI, 1.001-1.064; all P < 0.05). Measured serum osmolality demonstrated superior predictive performance for altered mental status [area under the receiver operating characteristic curve (AUROC), 0.751] and AKI (AUROC, 0.856) compared with calculated osmolality. Conclusion: Measured serum osmolality is strongly associated with clinical severity and outcomes in pediatric DKA. Incorporating it into clinical guidelines may improve risk stratification and management of pediatric hyperglycemic crises.