title: Using continuous glucose monitoring to assess contributions of premeal and postmeal glucose levels in diabetic patients treated with metformin alone.
abstract: OBJECTIVE
  This study aimed to determine the contributions of basal excess glycaemia (BEG) and prandial excess glycaemia (PEG) to overall excess glycaemia in type 2 diabetes (T2D) patients treated with metformin alone.
  
  
  METHODS
  Outpatients with T2D treated with metformin alone (n=46) who underwent continuous glucose monitoring (CGM) were divided into tertiles according to glycated haemoglobin (HbA1c) levels. For each CGM trace, the glucose area under the curve (AUC)>5.5mmol/L was expressed as the AUCoverall, representing overall excess glycaemia. The sum of glucose AUCs above the premeal glucose level at 4h after breakfast, lunch and dinner was expressed as the AUCpeg, representing PEG. The contribution of PEG to overall excess glycaemia was calculated as (AUCpeg/AUCoverall)×100%. The contribution of BEG was calculated as [(AUCoverall-AUCpeg)/AUCoverall]×100%. Factors related to PEG contribution were also analysed.
  
  
  RESULTS
  BEG constituted more than half the overall excess glycaemia in all HbA1ctertiles. The contribution of PEG was negatively correlated with HbA1cand mean glucose values before each meal. Prebreakfast and predinner glucose values were the dominant factors affecting PEG contribution and was independent of HbA1c.
  
  
  CONCLUSIONS
  In patients treated with metformin alone, BEG was the major contributor to excess glycaemia at HbA1clevels ≥7.7%, while PEG and BEG contributions were similar and stable below this level. For HbA1clevels ≥7.7%, add-on therapy to metformin should preferentially target control of BEG, whereas targeting both BEG and PEG could be of equivalent importance with lower HbA1clevels.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: S-D
authors.initials: SD
authors.lastname: Lin
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: S-L
authors.initials: SL
authors.lastname: Su
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Wang
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: S-T
authors.initials: ST
authors.lastname: Tu
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan. Electronic address: 67781@cch.org.tw.
authors.forename: S-R
authors.initials: SR
authors.lastname: Hsu
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D062407:Meals; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D008687:Metformin
keywords: Basal glycaemia; Continuous glucose monitoring; Metformin; Prandial glycaemia; Type 2 diabetes