Self-monitoring of blood glucose in non-insulin treated patients with type 2 diabetes: a systematic review and meta-analysis

Abstract

Objective:

To assess the effect of self-monitoring of blood glucose (SMBG) on glycaemic control in non-insulin treated patients with type 2 diabetes by means of a systematic review and meta-analysis.

Research design and methods:

MEDLINE and the Cochrane Controlled Trials Register were searched from inception to January 2009 for randomised controlled trials comparing SMBG with non-SMBG or more frequent SMBG with less intensive SMBG. Electronic searches were supplemented by manual searching of reference lists and reviews. The comparison of SMBG with non-SMBG was the primary, the comparison of more frequent SMBG with less intensive SMBG the secondary analysis. Stratified analyses were performed to evaluate modifying factors.

Main outcome measures:

The primary endpoint was glycated haemoglobin A_1c (HbA_1c), secondary outcomes included fasting glucose and the occurrence of hypoglycaemia. Using random effects models a weighted mean difference (WMD) was calculated for HbA_1c and a risk ratio (RR) was calculated for hypoglycaemia. Due to considerable heterogeneity, no combined estimate was computed for fasting glucose.

Results:

Fifteen trials (3270 patients) were included in the analyses. SMBG was associated with a larger reduction in HbA_1c compared with non-SMBG (WMD −0.31%, 95% confidence interval −0.44 to −0.17). The beneficial effect associated with SMBG was not attenuated over longer follow-up. SMBG significantly increased the probability of detecting a hypoglycaemia (RR 2.10, 1.37 to 3.22). More frequent SMBG did not result in significant changes of HbA_1c compared with less intensive SMBG (WMD −0.21%, 95% CI −0.57 to 0.15).

Conclusions:

SMBG compared with non-SMBG is associated with a significantly improved glycaemic control in non-insulin treated patients with type 2 diabetes. The added value of more frequent SMBG compared with less intensive SMBG remains uncertain.

Key words::

• Blood glucose self-monitoring
• Diabetes mellitus
• type 2
• Haemoglobin A
• glycosylated
• Meta-analysis
• Self care

Transparency

Declaration of funding

This study was supported by the Swiss Diabetes Association and the Swiss Diabetes Foundation (unrestricted grant to S.A.) and the Swiss National Science Foundation (grant 3233B0–115212 to C.S.). The funders had no role in study design, data collection, data analysis, data interpretation or writing of the report.

Declaration of financial/other interests

P.D. serves as a consultant for Roche Diagnostics, has received speaker fees from Bayer and Roche Diagnostics as well as research support from Roche Diagnostics. The other authors have disclosed that they have no relevant financial relationships.

Peer reviewers may receive honoraria from CMRO for their review work. Peer Reviewer 1 has disclosed he/she is a stock holder of Merck & Co. Inc.; Peer Reviewer 2 has disclosed that he/she has no relevant financial relationships.

Acknowledgements

We thank Dr Sharon Brown from the School of Nursing, University of Texas at Austin for checking data extracted from the publication and providing additional information.