A study published on BMJ claims that intake of both
metformin, an oral glucose lowering drug, and insulin instead of insulin alone
may not benefit patients suffering from type 2 diabetes.
The researchers say the combination leads to better blood
sugar control, less weight gain and less need for insulin. However, they also
suggest that more trials are needed to provide firm evidence about the long
term benefits and harms of the combination and specifically about the risks of
Metformin, the glucose lowering drug, is currently
recommended by guidelines for patients with type 2 diabetes starting on
The authors of the study, from the Copenhagen Trial Unit, Steno Hospital,
and the Copenhagen
reviewed 2217 patients in total, all of whom had type 2 diabetes and were over
18 years old.
The reporting of patient important outcomes, such as total
mortality and deaths from cardiovascular disease, was very sparse among the
Twenty trials reported that levels of HbA1c (a measure of
average blood sugar levels over time) were reduced with the combined use of the
drugs. Body mass index (BMI) and weight gain were also significantly reduced by
metformin plus insulin by an average of 1.6 kg.
The authors say that, owing to the risk of severe hypoglycemic
attack increasing with the use of metformin plus insulin, there should be
further research on the long term benefits and harms of the combination of the
In this week's BMJ podcast Trish Groves (BMJ's deputy
editor) talks to first author Bianca Hemmingsen about how the researchers were
able to draw on more data than previous analyses, and how they looked at
mortality and major complications rather than surrogate outcomes like weight
and blood glucose levels. Dr Hemmingsen discusses the lack of evidence for
answering whether insulin and metformin or insulin alone is best for patients,
and how trials are urgently needed.