Frequency of SMBG correlates with HbA1c and acute complications in children and adolescents with type 1 diabetes

The aim of this study was to correlate the frequency of self-monitoring of blood glucose (SMBG) to the quality of metabolic control as measured by hemoglobin A1c (HbA1c), the frequency of hypoglycemia and ketoacidosis, and to see whether the associations between SMBG and these outcomes are influenced by the patient's age or treatment regime. We analyzed data from the DPV-Wiss-database of 26 723 children and adolescents aged 0-18 yr with type 1 diabetes recorded during 1995-2006. Variables evaluated were gender, age at visit, diabetes duration, therapy regime, insulin dose, body mass index-standard deviation scores (BMI-SDS), HbA1c, rate of hypoglycemia, and ketoacidosis. In the youngest age group of children under the age of 6 yr, the frequency of SMBG was the highest compared with that in children aged 6-12 yr or children aged > 12 yr: 6.0/d vs. 5.3/d vs. 4.4/d (p < 0.001). Frequency of SMBG differed significantly also in the different groups of treatment (p < 0.001), but only for the continuous subcutaneous insulin infusion (CSII) group the frequency was considerably higher: 5.3/d (CSII) vs. 4.7/d (multiple daily injections) vs. 4.6/d (conventional therapy). Adjusted for age, gender, diabetes duration, year of treatment, insulin regimen, insulin dose, BMI-SDS, and center difference, SMBG frequency was significantly associated with better metabolic control with a drop of HbA1c of 0.20% for one additional SMBG per day (p < 0.001). Increasing the SMBG frequency above 5/d did not result in further improvement of metabolic control. A higher frequency of SMBG measurements was related to better metabolic control. But only among adolescents aged > 12 yr, metabolic control (HbA1c) improved distinctively with two or more blood glucose measurements.