Low dose aspirin – pro or con?

The US Preventative Services Task Force now recommends that all 50 to 70 year olds take a low-dose aspirin for preventing cardiovascular disease.
Medical press last week gave this story legs, and I’m puzzled as to why?

Current Australian Heart Foundation guidelines reflect the position that there are no or minimal cardiovascular benefits. In fact, the benefits are outweighed by the bleeding complications, according to the Foundation.

Two detailed reviews were conducted and published in the November 21st 2013 issue of the European Heart Journal. In the first study, the aim was to review the updated evidence for the efficacy and safety of low-dose aspirin in preventing heart attacks in patients who had not experienced a prior heart attack (primary prevention). Results from nine completed primary prevention trials were compiled, and included over 1000,000 participants, with an average follow-up of 6 years.

The analysis showed similar results to the individual studies. There is no benefit, and significant risk. The question needs to asked:

“Why is aspirin used relatively liberally for primary prevention, particularly in countries like the USA, despite these regulatory constraints and medical uncertainties?”

The second review actually provided a better answer to the question because it focused a bit more on the topic of bias in the medical literature. The author noted:

“Many of the published studies of aspirin have a peculiar similarity in that they were clearly neutral, but published as having a positive result”.

In other words, the study showed no overall benefit with aspirin therapy, yet in the reporting of the result, that’s not the message. For example, in the US Physician’s Health Study it was reported that there was a substantial 44% reduction in fatal and non-fatal myocardial infarction with aspirin therapy. However, the real truth is that the total number of fatal myocardial infarctions and sudden deaths was no different in the aspirin group when compared to the placebo group.

Yes, there was a significant decrease in non-fatal heart attacks, but there was NO difference in the number of people dying between these groups.

It was suggested that aspirin conceals rather than prevents heart attacks. It if truly was effective in reducing heart attacks it should also reduce death due to heart attack. The author of the study states that “for primary prevention, aspirin does not”.

What options will you discuss with your patients, or will you happily endorse low-dose aspirin?

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