Newsline THE USE OF ASPIRIN as a primary prevention for atherosclerotic cardiovascular disease (ASCVD) in high-risk patients has been controversial.Aspirin is known to lower the risk of heart attack and stroke, but it also may increase the risk of major bleeding episodes. In a new study, researchers have found no evidence that the use of aspirin for higher-risk primary prevention is beneficial. The findings were published in The American Journal of Medicine. The study authors used a database to examine all prospective randomized clinical trials (RCTs) that tested aspirin as a primary prevention method for ASCVD. A total of 12 RCTs that compared aspirin with nonaspirin (either placebo or control) for primary ASCVD prevention were identified (n=145,435).
Patients treated with aspirin had a statistically significant reduction in ASCVD events compared with no aspirin (4.7 vs 5.3 events per 1000 patient-years). Despite the beneficial effects, the authors found a statistically significant increase in major bleeding events for patients treated with aspirin compared with control patients (2.5 vs 1.8 events per 1000 patient-years). “These results trended toward an increased benefit for aspirin in higher-risk patients, but this finding did not meet statistical significance,” the researchers reported. In studies published prior to 2010 (n=7) and during or after 2018 (n=5), aspirin use resulted in a statistically significant reduction of ASCVD events. Researchers found that aspirin had a greater treatment effect in older trials
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Assessing Safety of Aspirin in High-Risk Patients With Atherosclerotic CV Disease
A significant increase in major bleeding events was seen with aspirin therapy.
compared with newer trials. The study authors found no heterogeneity of treatment effect between higher vs lower doses of aspirin and major bleeding events. “Despite the thought that aspirin for primary prevention may still be useful for those at high risk for ASCVD, insufficient randomized data currently exist to recommend aspirin in this group,” concluded the authors.
Antibiotic Use May Reduce Efficacy of Hormonal Oral Contraceptives THE EFFICACY OF hormonal contraceptives may be reduced with use of antibiotics, according to a study published online in BMJ Evidence-Based Medicine. Jeffrey K. Aronson, MBChB, DPhil, from Oxford University and Robin E. Ferner, MD, from the University of Birmingham, both in the United Kingdom, examined whether antibiotics impair the effectiveness of oral contraceptives in a database review of Yellow Card reports to the UK Medicines and Healthcare products Regulatory Agency. Data were included from spontaneous reports of suspected adverse drug reactions in people taking antibacterial drugs (74,623), enzyme-inducing medicines (32,872), or control medicines (65,578).
The researchers found that unintended pregnancies were 7 and 13 times more commonly reported with antibiotics and enzyme inducers (positive controls), respectively, compared with control medicines. Congenital abnormalities were not more common with antibiotics, but were reported 7 times more often with enzyme inducers. Diarrhea was not identified as a confounding factor. “This evidence suggests that there is an interaction of antibacterial drugs with hormonal contraceptives, which can potentially impair the effectiveness of the contraceptives,” the authors write. “The precautionary principle dictates that women taking hormonal contraceptives should be advised to take extra contraceptive precautions when a short course of an antibacterial drug is added.”
6 THE CLINICAL ADVISOR • OCTOBER 2020 • www.ClinicalAdvisor.com
