Plasma glucose levels throughout the day and HbA(1c) interrelationships intype 2 diabetes - Implications for treatment and monitoring of metabolic control

OBJECTIVE - To evaluate the extent of plasma glucose excursions with meals, the relations between plasma glucose levels at different times of the day, and the relations between the latter and HbA(1c) in non-insulin-treated ty pe 2 diabetic subjects. RESEARCH DESIGN AND METHODS - Daily glucose profiles were assessed in non-i nsulin-treated type 2 diabetic patients. Outpatients at the diabetes clinic (n = 371; one daily plasma glucose profile) and at home (n = 30; five dail y blood glucose profiles over 1 month) as well as inpatients (n = 455; prof ile of plasma glucose on the day of admission) were examined Subjects had p lasma/blood glucose assessment before and 2-3 h after breakfast, lunch, and dinner. HbA(1c) was also measured. RESULTS - After the meals many subjects had glucose levels >8.9 mmol/l (160 mg/dl) and/or glucose excursions >2.2 mmol/l (40 mg/dl). This was also oft en found when HbA(1c) was satisfactory (<7%). The coefficients of simple co rrelation among plasma/blood glucose at different times of the day ranged f rom 0.52 to 0.88. Correlations between HbA(1c) and plasma/blood glucose at different times of the day ranged from 0.44 to 0.67. The strongest correlat ion was between HbA(1c) and mean daily glucose (r = 0.57-0.69). Multiple re gression analyses showed that premeal but not postmeal plasma/blood glucose levels were independent predictors of HbA(1c). CONCLUSIONS - These results suggest that 1) the majority of non-insulin-tre ated type 2 diabetic patients have exaggerated plasma/blood glucose excursi ons with meals, and many of them have higher-than-recommended glucose conce ntrations 2 h after the meals; 2) plasma/blood glucose levels throughout th e day are not as strongly interrelated as one might believed and 3) HbA(1c) is more related to preprandial than postprandial plasma/blood glucose leve ls. These findings have potential implications for treatment and monitoring of metabolic control in type 2 diabetes.