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Low-Dose Aspirin Doesn't Increase Brain Hemorrhage Risk

Randomized trials of aspirin prophylaxis have indicated that aspirin may confer a small risk for intracerebral hemorrhage, which might partly offset its beneficial effects. However, most of these studies have had small numbers of cases of intracerebral hemorrhage and little power to identify subgroups at risk. Australian investigators performed this case-control study to more clearly define the risk for intracerebral hemorrhage in people taking aspirin. During a two-year period, 331 confirmed cases of primary intracerebral hemorrhage and 331 age- and sex-matched controls were identified in one city.

Five percent of cases and 6 percent of controls reported regular use of low doses of aspirin (1,225 mg/wk or less), while 6 percent and 3 percent, respectively, reported use of moderate to high doses (more than 1,225 mg/wk). After controlling for such confounders as hypertension, cholesterol level, diabetes, previous cardiovascular disease, body-mass index, exercise, alcohol intake, and smoking, the odds ratio for intracerebral hemorrhage was 0.86 with low doses of aspirin, a nonsignificant difference. Moderate to high doses yielded a significantly higher rate of stroke (odds ratio, 3.05). Subgroups defined by confounders had no evidence of an increased risk. An analysis of the use of other nonsteroidal anti-inflammatory drugs yielded similar results.

Comment: While these findings may be influenced by the recall bias and confounding typical of case-control studies, the results suggest that regular use of low-dose aspirin is not associated with an increased risk for cerebral hemorrhage.

— KI Marton

Published in Journal Watch General Medicine April 23, 1999

Citation(s):

Thrift AG et al. Risk of primary intracerebral haemorrhage associated with aspirin and non-steroidal anti-inflammatory drugs: Case-control study. BMJ 1999 Mar 20 318 759-764.

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