Optimal Cut-Offs of Body Mass Index and Waist Circumference to Identify Obesity in Chinese Type 2 Diabetic Patients

Qinying Zhao; Xiangjun Chen; Jinshan Wu; Lilin Gong; Jinbo Hu; Shumin Yang; Qifu Li; Zhihong Wang

doi:10.2147/DMSO.S251574

Optimal Cut-Offs of Body Mass Index and Waist Circumference to Identify Obesity in Chinese Type 2 Diabetic Patients

Diabetes Metab Syndr Obes. 2020 Jun 3:13:1899-1909. doi: 10.2147/DMSO.S251574. eCollection 2020.

Authors

Qinying Zhao^#¹, Xiangjun Chen^#¹, Jinshan Wu¹, Lilin Gong¹, Jinbo Hu¹, Shumin Yang¹, Qifu Li¹, Zhihong Wang¹

Affiliation

¹ Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.

^# Contributed equally.

Abstract

Purpose: The prevalence of general obesity (commonly defined by body mass index (BMI) in kg/m²) and abdominal obesity (commonly assessed by waist circumference (WC)) has increased rapidly in China. The aim of this study was to investigate the diagnostic accuracy of traditional cut-offs for BMI or WC to identify general or abdominal obesity in Chinese type 2 diabetic patients and propose optimal cut-offs.

Patients and methods: BMI and WC were obtained from 1539 type 2 diabetic patients. Body fat percentage and visceral fat area measured by dual-energy x-ray absorptiometry were set as the gold standard to identify general and abdominal obesity. We assessed the diagnostic power of traditional cut-offs for BMI and WC to define obesity, and analyzed receive operating characteristic (ROC) curves to obtain the optimal cut-offs to identify obesity in Chinese type 2 diabetic patients.

Results: In Chinese type 2 diabetic patients, the optimal BMI was 25 kg/m² with the best trade-off between sensitivity and specificity (men: 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; women: 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) in both genders. The optimal WC was 93 cm in men and 90 cm in women with the best trade-off between sensitivity and specificity (men: 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; women: 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).

Conclusion: For the Chinese patients with type 2 diabetes, the optimal cut-offs for BMI or WC to identify general or abdominal obesity need to be reconsidered.

Keywords: body mass index; diagnostic test; dual-energy X-ray absorptiometry; type 2 diabetes; waist circumference.

Grants and funding

This work was supported by the National Natural Science Foundation of China (grant number 81700754); the Technological Innovation and Application Development Project of Chongqing (grant number cstc2019iscx-msxmX0207); Chongqing Science and Health Joint Medical Research Project (grant number 2018GDRC004); High-end Medical Talents of Middle-aged and Young People in Chongqing (yuweiren (2015)49). Bethune Merck diabetes research fund (grant number G2018030).The author reported non-financial interests in this work.