Aspirin for Primary Prevention of Cardiovascular Disease Events

Abstract

Aspirin has been used for the prevention and treatment of cardiovascular disease (CVD) for several decades. The efficacy of aspirin for secondary prevention of cardiovascular disease is well established, but the clinical benefit of aspirin for primary prevention of CVD is less clear. The primary literature suggests that aspirin may provide a reduction in CVD events, but the absolute benefit is small and accompanied by an increase in bleeding. For aspirin to be beneficial for an individual patient, the risk of a future CVD event must be large enough to outweigh the risk of bleeding. The estimation of CVD risk is multifaceted and can involve numerous risk scores and assessments of concomitant comorbidities that confer additional CVD risk. Numerous guidelines provide recommendations for the use of aspirin for primary prevention, but they often contradict one another despite being based on the same clinical trials. Additional literature suggests that the presence of comorbidities that increase CVD risk, such as diabetes mellitus, asymptomatic peripheral arterial disease, or chronic kidney disease, does not ensure that aspirin therapy will be beneficial. Ongoing clinical trials may provide additional insight, but until more data are available, an individualized assessment of CVD risk with careful evaluation of risk and benefit should be performed before recommending aspirin therapy for primary prevention of CVD.

The Role of Aspirin in the Prevention of Cardiovascular Disease

“…36 Despite the relatively small reduction in mortality demonstrated in trials of aspirin for primary CVD prevention, there is a clear reduction in the risk of incident CVD events and several organizations, including the American Heart Association (AHA), the American College of Chest Physicians, the U.S. Preventative Task Force (USPSTF), and the European Society of Cardiology (ESC), have concluded that aspirin is beneficial and safe for primary CVD prevention when used properly. 15 Considering the conflicting data, physicians must be cognizant of their role in assessing the potential for benefit and subsequent risk of bleeding in individual patients prior to making recommendations.…”

“…15 For example, the Canadian Cardiovascular Society (CVS) maintains that the number of primary serious cardiovascular events prevented is offset by the risk of bleeding. 10 An additional concern of the CVS is the age of the primary prevention trials, which occurred before the widespread use of other prevention therapies such as statins.…”

“…The role of aspirin for primary CVD prevention remains controversial, however, particularly in Europe, due largely to the potential for major bleeding as an adverse effect. 15 In the last 30 years, nine major trials have examined the benefit of aspirin for primary CVD prevention, including the British Doctors' Trial, 16 Physicians' Health Study, 17 Thrombosis Prevention Trial, 18 Hypertension Optimal Treatment, 19 Primary Prevention Projects, 20 Women's Health Study, 21 Prevention of Progression of Arterial Disease and Diabetes, 22 Japanese Primary Prevention of Atherosclerosis, 23 and Aspirin for Asymptomatic Atherosclerosis 24 trials (table 1). Trial results were published between 1988 and 2010 and included a mix of healthy subjects and subjects with elevated CVD risk based on signs of underlying atherosclerotic disease or the presence of diabetes mellitus.…”

“…Difficulties arise when defining CVD risk, as many scoring systems and other metrics have been developed, but their availability and ease of used varies in different settings. 15,49 For example, the AHA guidelines are based on the Framingham Risk Score, 50 while the ESC uses the Systematic Coronary Risk Evaluation model for cardiovascular disease mortality. 51 The USPSTF recently performed a systematic review of CVD risk assessment tools and found that patient characteristics, such as comorbid diabetes mellitus, also affect the validity of scoring systems.…”

Effect of Low-Dose Aspirin on Primary Prevention of Cardiovascular Events in Japanese Diabetic Patients at High Risk

“…13 The 2 recommendations from the USA and Europe were based on the same meta-analyses, but they gave the results a different interpretation. 17 We have already reported in sub-analyses of the JPAD trial that low-dose aspirin was ineffective in preventing cardiovascular events in diabetic patients at high risk (those with decreased renal function 18 or receiving insulin therapy 19 ). Patients with an estimated glomerular filtration rate (eGFR) <60 ml · min −1 · 1.73 m −2 had a high rate of cardiovascular events, but the preventive effect of aspirin was not observed; in the patients with eGFR 60-89 ml · min −1 · 1.73 m −2 , however, aspirin significantly reduced cardiovascular events.…”