Risk of primary intracerebral haemorrhage associated with aspirin and non-steroidal anti-inflammatory drugs: case-control study.

OBJECTIVE To examine the association between use of aspirin or other non-steroidal anti-inflammatory drugs and intracerebral haemorrhage. DESIGN Case-control study. SETTING 13 major city hospitals in the Melbourne and metropolitan area. SUBJECTS 331 consecutive cases of stroke verified by computed tomography or postmortem examination, and 331 age (+/- 5 years) and sex matched controls who were community based neighbours. INTERVENTIONS Questionnaire administered to all subjects either directly or by proxy with the next of kin. Drug use was validated by reviewing prescribing records held by the participants' doctors. MAIN OUTCOME MEASURES Previous use of aspirin or other non-steroidal anti-inflammatory drugs. RESULTS Univariate analysis showed no increased risk of intracerebral haemorrhage with low dose aspirin use in the preceding 2 weeks. Using multiple logistic regression to control for possible confounding factors, the odds ratio associated with the use of aspirin was 1.00 (95% confidence interval 0.60 to 1. 66, P=0.998) and the odds ratio associated with the use of other non-steroidal anti-inflammatory drugs was 0.85 (0.45 to 1.61, P=0. 611) compared with respective non-users in the preceding fortnight. Moderate to high doses of aspirin (>1225 mg/week spread over at least three doses) yielded an odds ratio of 3.05 (1.02 to 9.14, P=0. 047). There was no evidence of an increased risk among subgroups defined by age, sex, blood pressure status, alcohol intake, smoking, and the presence or absence of previous cardiovascular disease. CONCLUSIONS No increase in risk of intracerebral haemorrhage was found among aspirin users overall or among those who took low doses of the drug or other non-steroidal anti-inflammatory drugs. These data provide evidence that doses of aspirin usually used for prophylaxis against vascular disease produce no substantial increase in risk of intracerebral haemorrhage.