The identification of
type 1 diabetes in diabetic subjects receiving
insulin therapy is sometimes difficult. The purpose of this study is to evaluate whether results of professional continuous
glucose monitoring can improve the identification of
type 1 diabetes.From 2007 to 2012, 119 adults receiving at least twice-daily
insulin therapy and professional continuous
glucose monitoring were recruited.
Type 1 diabetes was diagnosed by endocrinologists according to American Diabetes Association standards, including a very low
C-peptide level (<0.35 pg/mL) or the presence of
diabetic ketoacidosis. Continuous
glucose monitoring was applied for 3 days.Among 119 subjects, 86 were diagnosed with
type 1 diabetes. Subjects with
type 1 diabetes were younger (33.8 vs 52.3 years old, P < 0.001), had lower body mass index (BMI, 21.95 vs 24.42, P = 0.003), lower serum
creatinine (61.77 vs 84.65 μmol/L, P = 0.001), and higher estimated glomerular filtration rate (108.71 vs 76.48 mg/mL/min/1.73m2, P < 0.001) than subjects with
type 2 diabetes. Predictive scores for identification of
type 1 diabetes were constructed, including age, BMI, average mean amplitude of
glucose excursion in days 2 and 3, and the area under the curve of nocturnal hyperglycemic and
hypoglycemic states. The area under the receiver operating characteristic curve was 0.90. With the cutoff of 0.58, the sensitivity was 86.7% and the specificity was 80.8%. The good performance was validated by the leave-one-out method (sensitivity 83.3%, specificity 73.1%).Professional continuous
glucose monitoring is a useful tool that improves identification of
type 1 diabetes among diabetic patients receiving
insulin therapy.