A new study among older patients, confirms previous research that Avandia (rosiglitazone), a drug for Type 2 diabetes, is associated with an increased risk of heart failure and death, as compared to Takeda's Actos (pioglitazone).

The Canadian researchers say, in view of their findings it is difficult to justify the use of rosiglitazone for most patients, when it seems to have no substantial advantage over pioglitazone.

David Juurlink and colleagues of Sunnybrook Health Sciences Centre, Toronto writing about their findings in the British Medical Journal say, given the accumulating evidence that treating with rosiglitazone is harmful, including the lack of a distinct clinical advantage for pioglitazone or Actos, it is reasonable to question the justification of continuing to use rosiglitazone in treatments.

Once Glaxo's second biggest-selling product, Avandia's sales dropped significantly after a U. S. study linked it to an increased risk of heart attack, two years ago.

However, the Canadian study found no significant difference between Avandia and Actos' risk of heart attack.

Juurlink and colleagues using an insurance claims database, analyzed six year records (April 2002 and March 2008) for nearly 40,000-patients aged 66-plus, concluding that for every 93-patients taking Avandia instead of Actos, there was one additional cardiovascular event or death each year.

Reinforcing the Canadian study's message, two British-based experts confirm so-called thiazolidinedione drugs should not be given to patients with heart failure, a condition wherein the heart struggles to pump enough blood around the body.

However, contradicting the study's findings, Corinne de Vries, University of Bath and David Russell-Jones, University of Surrey say the claim that Actos is safer than Avandia is not fully supported, as differences between patients could have led to distortion in the data.

Also contesting the findings, Glaxo says they did not reflect the evidence of two randomised controlled trials that found no differences in heart failure, in their comparison of Avandia and Actos.

Glaxo, in order to compare the effect of the two drugs is enrolling patients into a long-term clinical trial that will also look at cardiovascular outcomes.