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Diabetes Medications and New Drugs

Avandia (Rosiglitazone) and the risk of heart attacks

Introduction

The blood glucose lowering drug Avandia, also known has Rosiglitazone has recently come under scrutiny over concerns that it may increase the risk of having a heart attack in people with diabetes.

This document examines the evidence and will give you the current state of knowledge on the subject so that you can make an informed decision. It is not our intention to advise you whether you should change your current treatment, but rather to place some of the facts at your disposal so that you may come to a reasonable conclusion.

Why the recent concern about Avandia?

The concerns with regard to Rosiglitazone and heart attacks stemmed from June 2007 with the publication of a research paper in a highly regarded Medical Journal, the New England Journal of Medicine. This paper concluded that Rosiglitazone or Avandia is associated with a small but significant increase in the risk of myocardial infarction.

Was the study of Avandia and heart attacks properly conducted?

It is important to understand that the research on Avandia and heart attacks was not based on a separate study on this subject. It was instead based on a statistical analysis of multiple research studies which were designed to look at other aspects of the drug. This type of analysis is called a ‘meta-analysis’.

What were the conclusions of the research into Avandia and myocardial infarction?

The authors pooled the results of 42 short-term clinical trial and found that patients taking Avandia were 43% more likely to have a heart attack or to have blocked coronary arteries than other patients.

These figures sound very alarming – what does ‘43% more likely’ mean?

If you have diabetes, your overall risk of having a heart attack is higher than in someone who does not have diabetes. In these studies of a total of fifteen and a half thousand patients on Avandia, there were 86 heart attacks and 39 deaths, compared with 72 heart attacks and 22 deaths among 12 thousand patients who didn’t take the drug.

As you would appreciate, the comparison of two different groups such as this, is not straightforward and the authors used statistical (mathematical) methods to reach their conclusions.

Have any other studies made similar claims?

A study published in the Journal of the American Medical Association (JAMA) pooled results from four long-term studies of Avandia. The authors of this paper concluded that Avandia raised the risk of having a heart attack by 42%.

Are there any flaws in this research?

The company which manufactures Avandia, Glaxo Smith Kline makes the argument that this method of statistical analysis of several unrelated studies, is inherently flawed.

The following flaws have been identified in the original paper.

  • only 11 of the 42 studies were peer-reviewed (i.e. scrutinized by other experts in the field)
  • 26 of the studies were not published in journals
  • most of the studies were ‘short’ – i.e. less than six months in duration
  • only three of the studies exceeded a year in duration

The package insert with my medication states that Avandia may cause heart problems

It has been known for a long time that both drugs in this group including Actos (Pioglitazone) contribute to fluid retention. This fluid retention may lead to heart failure in people who have a predisposition to this condition. It is important to recognise that the risk of heart failure and the risk of heart attacks or myocardial infarction are two completely separate issues. The increased chance of developing heart failure does not necessarily mean you will have an increased risk of having a heart attack.

What are the drug regulatory authorities doing?

The FDA (Food and Drug Administration) which is the American regulatory body which governs drug companies and licenses their products has examined in detail all the evidence relating to Avandia and the risk of heart attacks.

The FDA convened a group of expert panellists who voted that the drug increases the risk of heart attacks. However they also voted almost unanimously that the benefits of being on the drug outweighted the risks and recommended that it should remain on the market.

Is further evidence likely to become available?

The results of RECORD, a large clinical trial designed specifically to study cardiovascular outcomes with Rosiglitazone are currently awaited.

I am currently taking Avandia. Should I stop?

If you are taking Avandia or AvandaMet which is controlling your diabetes, it is not advisable to stop this medication without discussion with your doctor. Having read and understood the above information, should you feel your risk of having a heart attack is unacceptably high, make an appointment to see your doctor who will modify your treatment accordingly.

 

Dr Nishan Wijenaike
West Suffolk Diabetes Service
Bury St Edmunds
September 2007

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