Low-dose aspirin use lowers risk for recurrent adverse cardiovascular (CV) events in patients with known CV disease. Its benefit for primary prevention of CV events, especially in low-risk patients (those with 10-year risk <10%), is less clear given the risk for complications, particularly major bleeding. In this Italian study, researchers used a population-based database to identify 186,425 patients (mean age, 69) who took low-dose aspirin (81-83 mg) daily for at least 75 days and matched them to the same number of control patients who had the same bleeding propensity and did not use aspirin. During median follow-up of 5.7 years, 6907 episodes of major bleeding requiring hospitalization in aspirin and control patients occurred; about two thirds of bleeds were gastrointestinal, and one third were intracranial. The incidence rate was 5.58 events per 1000 person-years in aspirin users and 3.60 for nonusers, an excess of 2 per 1000 person-years.

Editorial: This is an observational study, and other factors could not be accounted for, these factors could change the outcome / conclusion of this study. Nevertheless, these are important data. An editorial that accompanied this study in JAMA,  puts these risks into perspective with the calculation that, for 10,000 patients without known cardiovascular (CV) disease followed for 1 year, aspirin would prevent about seven (7) major CV events and would cause four (4) major bleeding events. Not a big benefit! Other data have shown different results, , in 10,000 patients with known CV disease, aspirin use would prevent about 250 major CV events and would cause about 40 major bleeding events.

CITATION(S): 1. De Berardis G et al. Association of aspirin use with major bleeding in patients with and without diabetes. JAMA 2012 Jun 6; 307:2286.

2. Siller-Matula JM. Hemorrhagic complications associated with aspirin: An underestimated hazard in clinical practice? JAMA2012 Jun 6; 307:2318.

3. Journal Watch & Thomas L. Schwenk, MD