Trending Clinical Topic: Aspirin

Ryan Syrek


October 29, 2021

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A proposed change to recommendations for cardiovascular disease (CVD) prevention, along with studies on associations between aspirin and other conditions, resulted in this week's top trending clinical topic. New draft recommendations from the US Preventive Services Task Force (USPSTF) on the use of aspirin for primary CVD prevention limit the population in which it should be considered (see Infographic below).

The USPSTF states that low-dose aspirin in adults aged 40-59 years who have ≥ 10% 10-year CVD risk has a small net benefit and that the decision to use the medication should be made individually. Besides the recommendations for CVD prevention, the USPSTF also changed the previous recommendation of aspirin for prevention of colorectal cancer, given evidence generated from large primary CVD prevention trials. The draft recommendations will be available for public comment until November 8. Once it is finalized, the recommendation will replace the 2016 USPSTF recommendation on aspirin use to prevent CVD and colorectal cancer.

Some critics are concerned by the draft statement. Melissa Walton-Shirley, MD, a clinical cardiologist in Nashville, Tennessee, says that although she has no issue with the data, the public statement is incomplete at best and dangerous at worst. "As physicians, we understand how best to apply this information, but most lay people, some at significant cardiovascular risk, closed their medicine cabinets this morning and left their aspirin bottle unopened on the shelf," she wrote. "Some of these patients have never spent an hour in the hospital for cardiac-related issues, but they have mitigated their risk for myocardial infarction by purposely poisoning their platelets daily with 81 mg of aspirin. And they should continue to do so." She believes, at a minimum, the statement should have included a suggestion to consult a physician before discontinuing aspirin therapy.

A recent meta-analysis on aspirin in CVD prevention found support for a controversial "polypill concept." That refers to fixed-dose combinations of inexpensive generic cardiovascular drugs, whether or not in a single pill. A new patient-level analysis of three large, randomized trials included more than 18,000 participants, arguably enough to also examine whether adding aspirin to a mix of at least two hypertension medications and a statin made any difference to clinical outcomes across the trials (TIPS-3, HOPE-3, and PolyIran). Together, the trials suggest a highly significant 38% drop in risk for the meta-analysis primary endpoint — a composite of cardiovascular death, myocardial infarction, stroke, or arterial revascularization — in participants on the fixed-dose regimens, for a number needed to treat (NNT) of 52. Moreover, "The largest effects were with fixed-dose combination strategies that included aspirin," with a 47% drop in the primary endpoint and a smaller NNT of 37, said Philip Joseph, MD, Population Health Research Institute, Hamilton, Canada, when presenting the study during the all-virtual European Society of Cardiology Congress 2021. On the other hand, fixed-dose combination drug therapy also produced a significant primary endpoint benefit when aspirin wasn't included, observed Joseph, who is lead author on the study's report published August 29 in The Lancet.

In terms of aspirin's role in other conditions, a recent study found that aspirin and heparin increase bleeding risk during endovascular therapy (EVT). New data showed that treatment with acetylsalicylic acid (ASA) or heparin was associated with an increased risk for symptomatic intracranial hemorrhage (sICH) in patients with ischemic stroke undergoing EVT. The investigators conducted the multicenter, randomized, controlled MR CLEAN-MED trial to evaluate the effect of intravenous ASA and heparin, alone or in combination, during EVT for acute ischemic stroke. The ASA group had a significantly increased risk for sICH compared with the no-ASA group (14% vs 7.2%; adjusted odds ratio [aOR], 1.95). The rate of sICH was 11% in the group that received low-dose heparin; it was 26% in the group that received moderate-dose heparin (aOR, 6.05). The mortality rate was 23% in the low-dose group and 47% in the moderate-dose group (aOR, 5.45).

A separate study also found benefit of low-dose aspirin in women with systemic lupus erythematosus who are at risk for preeclampsia. In a prospective, real-world study of 190 pregnancies in 148 women, aspirin starting around 16 weeks' gestation was associated with a lower risk for preeclampsia than was no aspirin use (aOR, 0.21; P < .05). The overall rate of preeclampsia in the study population was 13.2%. Rates in each of the four treatment groups were 15.4% with aspirin alone, 7.7% with hydroxychloroquine alone, 14% with both drugs, and 14.5% with neither.

From new recommendations regarding CVD prevention to other potential risks and benefits, possible practice-changing news resulted in aspirin become this week's top trending clinical topic.

Read more on heart disease prevention.


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