Cheng Li1, Xiaojing Ma1, Jun Yin1, Yifei Mo1, Lei Zhang1, Jingyi Lu1, Wei Lu1, Yuqian Bao1, Robert A Vigersky2, Jian Zhou3, Weiping Jia4. 1. Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai, China. 2. Diabetes Institute of the Walter Reed National Military Medical Center, Bethesda, MD; Medtronic Diabetes, Northridge, CA, USA. 3. Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai, China. Electronic address: zhoujian@sjtu.edu.cn. 4. Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai, China. Electronic address: wpjia@sjtu.edu.cn.
Abstract
AIMS: To investigate the frequency of dawn phenomenon (DP) and its relationship with time in range (TIR) and glycemic variability (GV) using continuous glucose monitoring (CGM). METHODS: 781 subjects of a multicenter CGM study in China were included: those with normal glucose tolerance (NGT n=360); impaired glucose regulation (IGR n=173); newly diagnosed type 2 diabetes mellitus (T2D n=248). Analysis of the magnitude of DP (ΔG) was conducted with the primary definition of 1.11 mmol/L and a secondary definition of 0.56 mmol/L. RESULTS: The frequency of DP was 8.9%, 30.1% and 52.4% in NGT, IGR and T2D group, respectively, using the primary definition. In all three groups, TIR was lower (all P<0.05), coefficient of variation (CV) was higher in DP subgroup (all P<0.05). In DP subgroup of T2D, TIR was 7.0% (1.68h) lower and CV was 3.0% higher, and HbA1c was 0.6% (7 mmol/mol) higher using the primary definition (all P<0.05). CONCLUSIONS: DP was present in a high percent of subjects with NGT and IGR. In newly diagnosed T2D group, the presence of DP was associated with poorer overall glycemic control.
AIMS: To investigate the frequency of dawn phenomenon (DP) and its relationship with time in range (TIR) and glycemic variability (GV) using continuous glucose monitoring (CGM). METHODS: 781 subjects of a multicenter CGM study in China were included: those with normal glucose tolerance (NGT n=360); impaired glucose regulation (IGR n=173); newly diagnosed type 2 diabetes mellitus (T2D n=248). Analysis of the magnitude of DP (ΔG) was conducted with the primary definition of 1.11 mmol/L and a secondary definition of 0.56 mmol/L. RESULTS: The frequency of DP was 8.9%, 30.1% and 52.4% in NGT, IGR and T2D group, respectively, using the primary definition. In all three groups, TIR was lower (all P<0.05), coefficient of variation (CV) was higher in DP subgroup (all P<0.05). In DP subgroup of T2D, TIR was 7.0% (1.68h) lower and CV was 3.0% higher, and HbA1c was 0.6% (7 mmol/mol) higher using the primary definition (all P<0.05). CONCLUSIONS:DP was present in a high percent of subjects with NGT and IGR. In newly diagnosed T2D group, the presence of DP was associated with poorer overall glycemic control.