Objective: To perform a meta-analysis of randomized controlled trials (RCTs) and systematic reviews evaluating the efficacy of self-monitoring of blood glucose (SMBG) levels among patients with diabetes mellitus (DM).
Study design: Meta-analysis of RCTs among patients with DM not taking insulin comparing patients with SMBG versus those without SMBG and reporting results as change in glycosylated hemoglobin (A1C) values.
Methods: Prior systematic reviews and a PubMed search were used to identify studies. Data were extracted by trained physician reviewers working in duplicate. Trials were classified according to duration of the intervention, and random-effects meta-analysis was used to pool results.
Results: Three trials of SMBG of 3 months' duration were too heterogeneous to pool. Nine other trials were identified. Five trials of SMBG of 6 months' duration yielded a pooled effect estimate of a decrease in mean A1C values of -0.21% (95% confidence interval [CI], -0.38% to -0.04%). Four trials that reported outcomes of 1 year or longer yielded a pooled effect estimate of a decrease in mean A1C values of -0.16% (95% CI, -0.38% to 0.05%). Three trials reported hypoglycemic outcomes, which were increased in the patients using SMBG, although this mostly involved asymptomatic or mild episodes.
Conclusions: At most, SMBG produces a statistically significant but clinically modest effect in controlling blood glucose levels in patients with DM not taking insulin. It is of questionable value in helping meet target values of glucose control.