Glucose monitoring may not be cost effective

How much does self-monitoring of blood glucose improve the control of type 2 diabetes?

Checking blood glucose is an important part of the management of patients injecting insulin. Many patients with type 2 diabetes do not take insulin, so monitoring may be less important.

A group of international researchers has pooled the data from trials ofglucose monitoring in type 2 diabetes. The effect of monitoring was primarily assessed by changes in the concentrations of HbA1c.

There were six randomised controlled trials which were suitable for meta-analysis. These trials included 2552 patients with a mean age of 60 years who had had diabetes for a median of 36 months.

At baseline, the patients’ average HbA1c was 8.3% and their body mass index was 30.9kg/m2.

The trials lasted for 6–12 months during which HbA1c declined irrespective of whether glucose was monitored or not. 

Although the reduction was bigger in patients who self monitored, it was only 0.25% more than the fall in the control group at six months and 0.23% more at 12 months.

The favourable effect of self-monitoring was not significant inpatients under 45 or over 75 years-old. There was also no significant effect if the baseline HbA1c was 10% or more.

Self-monitoring had no significant effect on serum cholesterol. It also did not influence the control of systolic and diastolic blood pressure.

As 0.5% is a clinically relevant change in HbA1c, the small benefits of testing may be outweighed by its cost. The meta-analysis suggests that monitoring should not be routine.

Dr John Dowden