“An aspirin a day keeps the doctor away,” an age-old adage revised to support stroke prevention, may no longer be relevant in light of new data presented at the European Society of Cardiology (ESC) Scientific Congress 2018 in Munich, Germany. Of course we have known for some time—and data continue to support us—that aspirin is highly effective in secondary prevention of cardiovascular disease (ie, in patients who have already had an adverse vascular event). However, aspirin’s benefit in primary prevention is controversial and its use has generally been recommended for those who are considered at particularly high risk for CVD, such as patients with diabetes, smokers, or those with multiple CV risk factors. (There are also observational data that show a lower risk of colon cancer with aspirin therapy.)
Results of 2 large randomized controlled trials looking at the benefit of aspirin in primary prevention were presented at ESC: ASCEND (A study of cardiovascular events in diabetes ) and ARRIVE (Aspirin to reduce risk of initial vascular events. ASCEND assessed 15 480 persons with diabetes with no baseline cardiovascular disease whereas ARRIVE assessed 12 546 patients who had multiple cardiovascular risk factors and were deemed at “moderate cardiovascular risk.” Notably, ARRIVE excluded patients with diabetes and those at high risk for bleeding.
ASCEND trial design, baseline characteristics, primary outcomes and brief discussion are summarized as follows:
- Design: 40+y with diabetes and no CV disease
- Characteristics: mean age 63y, 63% male, 83% overweight, 62% with HTN, 25% on insulin
- Randomized to: ASA 100 mg daily or placebo
- Mean followup: 7.4y
- Primary efficacy outcome: first serious vascular event (MI, CVA, TIA, death from vascular cause) excluding ICH.
- Reduction in event rate of 1.1%, RR 0.88 (0.79 - 0.97), p=0.01. NNT = 91.
- Primary safety outcome: 1st major bleeding event (ICH, GIB, bleeding in eye, other
- Increase in event rate of 0.9%, RR 1.29 (1.09 - 1.52), p=0.003. NNH=128.
Next: ASCEND conclusions