Objective: The purpose of this systematic review was 2-fold: first, to perform a comprehensive review of relevant studies on the impact of self-monitoring of blood glucose (SMBG) on HbA1c levels for patients with type 2 diabetes mellitus and, second, to explore mediators and moderators within a self-regulation framework.
Data sources: Five databases-Medline, PsychInfo, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing & Allied Health Literature (CINAHL)-were searched.
Study selection: Cross-sectional, longitudinal, and randomized control trials from 1990 to 2006, which included patients with type 2 diabetes not on insulin, were reviewed. In total, 6,769 studies were screened for inclusion, 89 were retrieved for detailed analysis, and 29 met criteria for inclusion in the review.
Data extraction: Data on the impact of SMBG on HbA1c, potential mediators and moderators, study design and participants, and limitations of each study were retrieved.
Data synthesis: Twenty-nine studies were included in this review: 9 cross-sectional studies, 9 longitudinal studies, and 11 randomized controlled trials. Evidence from the cross-sectional and longitudinal studies was inconclusive. Evidence from randomized controlled trials suggests that SMBG may lead to improvements in glucose control. Very few studies examined potential mediators or moderators of SMBG on HbA1c levels.
Conclusions: SMBG may be effective in controlling blood glucose for patients with type 2 diabetes. There is a need for studies that implement all the components of the process for self-regulation of SMBG to assess whether patient use of SMBG will improve HbA1c levels.