title: What is the relative contribution of blood glucose levels at different time points of the day to HbA1c in Type 1 diabetes?
abstract: OBJECTIVE
  To evaluate the relative contribution of blood glucose levels at different time points of the day to HbA(1c) in Type 1 diabetes.
  
  
  METHODS
  Consecutive home blood glucose records (n = 146) from 71 Type 1 diabetic patients who were on an intensive diabetes therapy programme were examined. Each home blood glucose record included six daily blood glucose profiles over 2 months. The relationship between glycaemic values at each time point and HbA(1c) measured at the end of each record period was analysed.
  
  
  RESULTS
  Significant linear correlations were found between HbA(1c) and glycaemia at each time point of the day (ranged from 0.413 to 0.593), the strongest being with predinner glycaemia (r = 0.593; P = 0.000). Total daily glycaemia, mean preprandial and mean postprandial glycaemia were also significant and linearly correlated with HbA(1c) (r = 0.701; r = 0.686; r = 0.620, respectively; P < 0.0001). Multiple linear regression analysis showed that predinner, prebreakfast and post-breakfast glycaemia correlated significantly and independently with HbA(1c). The model accounted for 47.8% of the variance in HbA(1c).
  
  
  CONCLUSIONS
  Our study shows that among individual time points, prebreakfast and predinner are those with more influence on HbA(1c) in Type 1 diabetes and, to a lesser extent, post breakfast. It also confirms that preprandial glycaemia better predicts overall glycaemic control in Type 1 diabetes than postprandial glycaemia.
authors.affiliation: Department of Endocrinology and Nutrition, University Hospital La Paz, P. Castellana 261, 28046 Madrid, Spain. nataliahillman@terra.es
authors.forename: N
authors.initials: N
authors.lastname: Hillman
authors.forename: L
authors.initials: L
authors.lastname: Herranz
authors.forename: C
authors.initials: C
authors.lastname: Grande
authors.forename: P M
authors.initials: PM
authors.lastname: Vaquero
authors.forename: L F
authors.initials: LF
authors.lastname: Pallardo
mesh_terms: D001786:Blood Glucose / Q000378:metabolism*; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D016014:Linear Models; D019518:Postprandial Period
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin