Simplifying the Evaluation of Children With New Onset Diabetes: Utility of Pancreatic Autoantibodies for Diabetes Type Classification and Use of Serum Bicarbonate to Diagnose and Classify Diabetic Ketoacidosis.

Abstract

Objectives: To assess whether routinely measuring pancreatic autoantibodies (PAA) in pediatric new onset diabetes (NODM) is necessary, and to evaluate serum bicarbonate (HCO3) as a substitute for venous pH (vpH) in the diagnosis of diabetic ketoacidosis (DKA). Methods: Retrospective analysis of all patients with NODM admitted to Boston Children's Hospital from 10/1/07-7/1/13. Logistic regression was used to develop a clinical score to classify diabetes type. Linear and logistic regression were used to assess serum HCO3 as a predictor of vpH and DKA, respectively. Results: Of 1089 patients (45.1% female, 76.7% white, age 10.6±4.5 years), < 6% had a change in diagnosis of diabetes type following PAA panel results. A scoring system using weight z-score, age and race had 91.7% sensitivity and 82% specificity to predict type 1 diabetes. In a subset of 690 patients (19.4% DKA), HCO3 predicted vpH using the formula vpH=6.81301+(0.17823*ln[HCO3]); R2 0.75 (p<0.001), DKA and severe DKA (c-statistic 0.97 [95% CI 0.96-0.99, p<0.001] and 0.99 [95% CI 0.991-0.999, p<0.001], respectively). Conclusions: A simple scoring system may reduce to ~15% the number of PAA measurements needed to classify diabetes type. Serum HCO3 concentration alone can substitute for vpH to diagnose DKA and classify severity in children with NODM.