Introduction: Self-monitoring of blood glucose (SMBG) is a crucial element of clinical care in type 1 diabetes, but it may not provide adequate glucose control. A newer alternative approach is continuous glucose monitoring (CGM) system, which allows a more thorough metabolic control. However, the results of trials comparing CGM with SMBG are inconsistent.
Objectives: Based on a systematic review and meta-analysis, we aimed to assess the efficacy and safety of various CGM systems compared with SMBG.
Methods: We searched major medical databases up to June 2011 for randomized controlled trials comparing CGM and SMBG in type 1 diabetes. Studies of at least 12-week duration were included. Weighted mean difference (WMD) or standardized mean difference (SMD) was calculated for continuous measures and dichotomous data were expressed as odds ratio (OR) or risk ratio.
Results: We identified 14 relevant trials including a total of 1268 type 1 diabetic patients, of whom 670 were randomized to the CGM group and 598 to the SMBG group. Patients using CGM had a greater decrease in hemoglobin A1c (HbA1c) from baseline compared with those using SMBG (WMD -0.26% [-0.34; -0.19]). We found that the magnitude of the effect was similar in the subset of children and adolescents (WMD -0.25% [-0.43; -0.08]) to that in adults (WMD -0.33% [-0.46; -0.2]). Only real-time devices for CGM improved glycemic control (WMD -0.27% [-0.34; -0.19]). The percentage of patients achieving target HbA1c was higher in the CGM group (OR 2.14 [1.41; 3.26]). Pooled results from 4 studies revealed a reduction in hypoglycemic events in the CGM group (SMD -0.32 [-0.52; -0.13]).
Conclusions: CGM, partcicularly its real-time system, has a favorable effect on glycemic control and decreases the incidence of hypoglycemic episodes in both adult and pediatric patients with type 1 diabetes.