Plasma glucose to glycated hemoglobin ratio: Method of differentiating fulminant type 1 diabetes from diabetic ketoacidosis

Objectives: In fulminant type 1 diabetes mellitus (fT1DM), plasma glucose (PG) levels are strongly increased, unlike glycated hemoglobin (HbA_1C) levels, resulting in a sharply increased PG/HbA_1C ratio. We investigated the PG/HbA_1C ratio in fT1DM and tested the accuracy of cutoff points to easily and efficiently differentiate fT1DM from diabetic ketoacidosis (DKA).

Methods: We report 41 cases of fT1DM in which PG/HbA_1C ratio was studied as a novel clinical parameter to predict fT1DM. Clinical and biochemical characteristics were analyzed in 41 fT1DM and 51 DKA patients in China. Receiver-operating characteristic curve analysis was used to identify PG/HbA_1C ratio cutoff points to differentiate fT1DM from DKA.

Results: PG/HbA_1C ratio was significantly higher in fT1DM patients (7.24±2.49mmol/L/%; i.e., 0.88±0.36L/mol) than in DKA patients (2.60±0.69mmol/L/%; i.e., 0.06±0.01L/mol) (P<0.001). PG/HbA_1C ratio exceeded 4.2mmol/L/% (i.e., 0.6 l/mol) in 39 of the 41 fT1DM patients (95.1%), versus only 1 of the 51 DKA patients (1.9%).

Conclusions: PG/HbA_1C ratio is a simple tool that may be useful to identify DKA patients at high risk of fT1DM. PG/HbA_1C ratio with a threshold of≥4.2mmol/L/% (i.e., 0.6L/mol) can be adopted as a new clinical parameter in predicting fT1DM.