Canadian Avandia study restates cardio risk in elderly

According to a new Canadian study, older patients who took GlaxoSmithKline's (GSK) type II diabetes pill Avandia (roseglitazone) had a higher risk of heart attacks, congestive heart failure and death than those on other diabetes treatments.

The study of 160,000 patients conducted by researchers at the Institute for Clinical Evaluative Science followed subjects aged over 65 years for four years. Older patients were not represented well in previous studies, according to study head, Dr Lorraine Lipscombe, an endocrinologist and researcher at the Institute for Clinical Evaluative Science.

The study, which was funded by the Ontario government and published in the Journal of the American Medical Association (JAMA), examined how older patients responded to Avandia or Japanese-headquartered Takeda's Actos (pioglitazone), compared with those on other diabetes treatments.

The US labelling for Avandia and Actos have carried a "black box" warning against their use in patients with advanced congestive heart failure. The Canadian study found Avandia raised heart failure risk even in patients with no history of the condition, suggesting the heart failure warning was inadequate.

Approximately eight per cent of patients were hospitalised for congestive heart failure or a heart attack during the study. Compared with patients on other diabetes treatments, those on only Avandia or Actos had a 60 per cent higher risk of congestive heart failure and a 40 per cent higher heart attack risk. They also had a 29 per cent higher risk of death.

According to Dr Lipscombe, the increased heart risks observed in the Avandia/Actos group were predominantly in patients taking Avandia. She stated that the results did not indicate that Actos was safer, but that the study might have enrolled fewer Actos patients to detect a higher risk.

In a statement to the US media, a spokeswoman for GSK said the problems with the study were obvious with regard to the CHF (congestive heart failure) findings. Avandia and Actos had well-documented and similar CHF events, yet this study somehow finds an increase in these events with Avandia compared with Actos, she added.

Steven Nissen, the Cleveland Clinic's chief of cardiovascular surgery, who initially raised concerns in his own investigation, said the Canadian study was independent, not funded by industry and had a huge sample size, adding it was real-life data.

The FDA has asked GSK to compare Avandia's heart attack risk with those of other diabetes treatments, but the trial itself is not expected to complete until March 2014.