Gaziano JM, et al. - Researchers performed a study to test the safety as well as the efficacy of aspirin vs placebo in patients with a moderate estimated risk of a first cardiovascular event. They observed that the event rate was much lower than expected, which is probably reflective of contemporary risk management strategies, making the study more representative of a low-risk population. Therefore, the role of aspirin in primary prevention among patients at moderate risk could not be addressed.

Methods

• ARRIVE is a randomised, double-blind, placebo-controlled, multicentre study done in seven nations.
• Eligibility criteria included patients were aged 55 years (men) or 60 years (women) and older and had an average cardiovascular risk, deemed to be moderate on the basis of the number of specific risk factors.
• Patients at high risk of gastrointestinal bleeding or other bleeding, or diabetes were excluded.
• For this analysis, patients were randomly assigned (1:1) with a computer-generated randomisation code to receive enteric-coated aspirin tablets (100 mg) or placebo tablets, once daily.
• After that, patients, investigators, and others involved in treatment or data analysis were masked to treatment allocation.
• A composite outcome of time to first occurrence of cardiovascular death, myocardial infarction, unstable angina, stroke, or transient ischaemic attack was the primary efficacy endpoint.
• Haemorrhagic events and incidence of other adverse events were safety endpoints, and were analyzed in the intention-to-treat population.

Results

• Twelve thousand, five hundred forty-six patients were enrolled and randomly assigned to receive aspirin (n=6270) or placebo (n=6276) at 501 study sites between July 5, 2007, and Nov 15, 2016.
• Findings revealed that median follow-up was 60 months.
• The primary endpoint occurred in 269 (4·29%) patients in the aspirin group vs 281 (4·48%) patients in the placebo group (hazard ratio [HR] 0·96; 95% CI 0·81–1·13; p=0·6038) in the intention-to-treat analysis.
• It was observed that gastrointestinal bleeding events (mostly mild) occurred in 61 (0·97%) patients in the aspirin group vs 29 (0·46%) in the placebo group (HR 2·11; 95% CI 1·36–3·28; p=0·0007).
• It was noted that the overall incidence rate of serious adverse events was similar in both treatment groups (n=1266 [20·19%] in the aspirin group vs n=1311 [20·89%] in the placebo group.
• In both treatment groups (n=5142 [82·01%] vs n=5129 [81·72%] in the placebo group), the overall incidence of adverse events was similar.
• Data reported that the overall incidence of treatment-related adverse events was low (n=1050 [16·75%] vs n=850 [13·54%] in the placebo group; p < 0·0001).
• They found that there were 321 documented deaths in the intention-to-treat population (n=160 [2·55%] vs n=161 [2·57%] of 6276 patients in the placebo group).