Forty studies were included in the review varying in duration from 3 months to 4 years. Eight of the studies actually contained cardiovascular endpoints as a primary or secondary endpoint with the remaining 32 studies contained this information by reporting serious adverse events.
The analysis found a statistically significant reduction in cardiovascular mortality when comparing treatment with metformin with other active treatments or placebo. There was also an increased risk of cardiovascular morbidity and mortality associated with rosiglitazone but this finding was not significant.
The authors conclude that, "Larger, long-term studies taken to hard end points and better reporting of cardiovascular events in short-term studies will be required to draw firm conclusions about major clinical benefits and risks related to oral diabetes agents".
Action: This analysis confirms current recommendations. Metformin is the first line hypoglycaemic and rosiglitazone should be avoided where alternatives exist.