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Two new reviews of glitazones

The Journal of the American Medical Association (JAMA) has published two meta analyses, the first reviewing the long-term cardiovascular risks of rosiglitazone and the second reviewing the effect of pioglitazone on ischaemic cardiovascular events.

Concerns have been raised about the cardiovascular safety of rosiglitazone following the publication of a meta analysis in the New England Journal of Medicine.

The new rosiglitazone analysis extracted data from 4 studies after screening 140. Studies were required to be randomised controlled studies of at least 12 months duration of rosiglitazone in the treatment or prevention of type 2 diabetes. The study was required to monitor for cardiovascular events and provided numerical data for adverse events.

This study found statistically significant increases in myocardial infarction (RR 1.42; 95% CI 1.06-1.91; P = 0.02) and heart failure (RR 2.09; 95% CI 1.52-2.88; P < 0.001).

No statistical difference was found in terms of the risk of cardiovascular mortality.

This analysis adds more weight to the assertion that rosiglitazone is implicated in causing cardiovascular events.

In the same issue of JAMA a second analysis examines the effect of pioglitazone on ischaemic cardiovascular events. This analysis was conducted independently using a database administered by the drug manufacturer. The database holds individual patient-level data collected during pioglitazone clinical trials. It includes data from 19 trials for over 16,000 patients.

A composite outcome of death, myocardial infarction or stroke was statistically less likely in patients taking pioglitazone (RR 0.82; 95% CI 0.72-.094; P = 0.005). The individual components of the primary outcome were also reduced and by a similar magnitude, although it is unclear if these reductions were statistically significant in the abstract. An expected increase in heart failure was also seen (RR 1.41; 95% CI 1.14-1.76; P = 0.002).

Action: As previously recommended, rosiglitazone use should be restricted. Clinicians may wish to consider changing patients who are currently taking rosiglitazone to a sulphonylurea or pioglitazone.