Optimal Cut-offs Of Body Mass Index And Waist Circumference To Identify Obesity In Chinese Type 2 Diabetic Patients

PurposeIn general population,general obesity usually measured by body mass index(BMI)and abdominal obesity commonly defined by waist circumference(WC).However,patients with type 2 diabetes mellitus(T2DM)are different from the general population,there are few studies to evaluate the accuracy of BMI and WC in diagnosis of obesity in patients with T2DM.This study was aimed to investigate the diagnostic power of traditional BMI or WC cut-off for general or abdominal obesity in Chinese patients with T2DM and to propose the optimal cut-offs.MethodsBMI and WC were measured in 1539 Chinese patients with T2DM,who had detailed body composition data,excluding secondary obesity or diagnosed malignancy.Body fat percentage(BF%)and visceral fat area(VFA)measured by dual-energy x-ray absorptiometry were used to diagnose general(BF%≥25%in men or 35%in women)and abdominal(VFA≥100cm~2)obesity.We evaluated the diagnostic efficacy of traditional BMI and WC cutoffs for obesity and drawn the receive operating characteristic curves to get the optimal cut-offs for the diagnosis of obesity.ResultsIn Chinese patients with T2DM,the optimal BMI with the best sensitivity and specificity was 25 kg/m~2(male:74.6%(95%CI:70.7–78.2%)and 65.1%(95%CI:59.7–70.3%),AUC 0.78(95%CI:0.75–0.81),p<0.05;female:65.8%(95%CI:60.3–71.0%)and 80.3%(95%CI:75.7–84.3%),AUC 0.80(95%CI:0.77–0.83),p<0.05).Similarly,the best WC for defining abdominal obesity was 93 cm(male)and 90cm(female)(male:87.2%(95%CI:84.3–89.8%)and 80.2%(95%CI:74.9–84.8%),AUC 0.91(95%CI:0.88–0.92),p<0.05;female:81.0%(95%CI:76.9–84.6%)and 88.7%(95%CI:83.9–92.4%),AUC 0.92(95%CI:0.90–0.94),p<0.05).ConclusionsFor Chinese patients with T2DM,the BMI or WC cut-offs for the diagnosis of general or abdominal obesity are not completely consistent with those for the general population.They are 25kg/m~2and 93 cm(male)or 90 cm(female),respectively.