Use of the Continuous Glucose Monitoring System to Guide Therapy in Patients With Insulin-Treated Diabetes: A Randomized Controlled Trial

OBJECTIVE To show improved glycemic control in patients with insulin-treated diabetes after adjustments to the diabetes management plan based on either continuous glucose monitoring using the Continuous Glucose Monitoring System (CGMS) or frequent self-monitoring of blood glucose (SMBG) using a home blood glucose meter. PATIENTS AND METHODS From January to September 2000, patients aged 19 to 76 years with insulin-treated diabetes were assigned to insulin therapy adjustments based on either CGMS or SMBG values. At the end of the study, patients in both groups used the CGMS for 3 days; these values were used to calculate measures of hypoglycemia. Repeated-measures analysis of variance with post hoc comparisons were used to test differences in hemoglobin A 1c levels and hypoglycemia between the 2 study groups. RESULTS A total of 128 patients were enrolled in the study. Nineteen discontinued study participation, leaving 51 in the CGMS group and 58 in the SMBG group. No significant differences were noted in demographics or baseline characteristics between the 2 groups. There were no significant differences in hemoglobin A 1c levels between the CGMS group and the SMBG group at baseline (9.1%±1.1% vs 9.0%±1.0%, P =.70), and both groups showed statistically significant ( P >.001) and similar ( P =.95) improvement in hemoglobin A 1c levels after 12 weeks of study. However, the CGMS group had a significantly shorter duration of hypoglycemia (sensor glucose, ≤60 mg/dL) at week 12 of the study (49.4±40.8 vs 81.0±61.1 minutes per event, P =.009). CONCLUSION Use of the CGMS to guide therapy adjustments in patients with insulin-treated diabetes reduces the duration of hypoglycemia compared with therapy adjustments guided by SMBG values alone.