OXFORD, UNITED KINGDOM. It is estimated that over 50 million Americans now take a daily aspirin in an attempt to ward off a stroke or heart attack. There is evidence that aspirin is somewhat effective in preventing a second stroke. It is estimated that one second stroke can be avoided for every 100 stroke patients treated with aspirin for a year. The evidence of benefit is somewhat murkier when it comes to prevention of a first heart attack. Here 555 people must be treated with aspirin for a year in order to claim the prevention of one heart attack.
Unfortunately, aspirin is not innocuous. It can cause serious bleeding in the gastrointestinal tract and can aggravate existing ulcers. The estimated death rate from gastrointestinal bleeding is 12 per cent. Researchers at Oxford University have just released the results of a very large study aimed at establishing the magnitude of aspirin-related bleeding incidents. They carefully studied the results of 24 major randomized clinical trials involving almost 66,000 participants. They conclude that when treated for a year 2.47 per cent of aspirin takers develop gastrointestinal bleeding as compared to 1.42 per cent among placebo takers. Put in terms of the 50 million Americans now taking aspirin this means that the excess incidence of gastrointestinal bleeding attributable to aspirin would be 525,000 and the excess mortality would be 63,000 every year.
The researchers also investigated whether lower dosages of aspirin would be safer. They found that they were not. The incidence of gastrointestinal bleeding among low-dose aspirin takers was 2.30 per cent compared with 1.45 per cent for placebo takers. Somewhat surprisingly, the study also found that enterically-coated or otherwise modified formulations were no safer than standard aspirin. The increase in gastrointestinal bleeding among users of modified formulations was 93 per cent as compared to 68 per cent for all aspirin users and 59 per cent for low-dose users.
The researchers conclude that patients and their physicians need to consider the trade-off between the
benefits and harms of long term aspirin use.
Dr. Martin Tramer of the Geneva University Hospitals in Switzerland wholeheartedly agrees with this
conclusion and adds, "It may be more appropriate for some people to eat an apple rather than an aspirin a