This large systematic review of 301 trials, published in JAMA
compared nine classes of glucose-lowering drugs – given alone or in combination – to treat type 2 diabetes. The researchers analysed data from direct comparisons
and from studies with dummy treatment arms together. Metformin worked best at keeping blood sugar levels under control and remains a good first choice as single
therapy. Overall, the drugs had similar effects on risk of death from cardiovascular causes and overall mortality, though estimates are imprecise because so few
people died in these studies. Risk of other side effects, such as weight gain or risk of low blood sugar did vary between treatments.
Read NIHR review