Aspirin, Women, and Second Hand Smoke: New Findings, Familiar Messages

by admin on December 9, 2011

DrSamGirgis.com has the pleasure of hosting the following post by contributing blogger, Dr. Richard Andraws MD, who is a Board Certified Cardiologist

When you think about it, aspirin is the apple of modern medicine: you can’t go wrong with having one every day. It keeps heart attacks and strokes away, or so goes common wisdom. But like any medication, aspirin has potential side effects. As an antiplatelet drug, it effectively thins the blood (though not as much as anticoagulants) and can increase bruising and more serious bleeding. This is particularly the case in the stomach, where it adversely affects the chemicals that create its protective lining.

So we come to the eternal question of risks versus benefits. Who benefits from aspirin therapy? According the American Heart Association and the European Society of Cardiology, it is those persons whose ten year risk of heart attack and stroke exceeds 10% and/or who are older than 65 years. Risk can be calculated using various formulas that take into account blood pressure and cholesterol levels, among other variables. But these guidelines may not be sufficient. Recent research has shown that using aspirin for primary prevention (i.e. in those who have never had a heart attack or stroke) is not as straightforward as once thought. It seems like we may be overusing aspirin, with the associated risk of harm and cost to patients and the healthcare system. When you factor in additional evidence that aspirin has differential effects on men versus women, the shine is definitely off the apple.

Dorresteijn and colleague examine this conundrum in a recent study published in European Heart Journal. This was a retrospective analysis of the Women’s Health Study (WHS). WHS was a large randomized trial of low dose aspirin (100 mg every other day) versus placebo and its effects on adverse cardiovascular outcomes. Over 10 years, the WHS demonstrated a trend toward fewer heart attacks, strokes and death but at a cost of more gastrointestinal bleeding, blood in the urine, nosebleeds and bruising. The current investigators sought to tease out which subgroups would benefit enough from aspirin to make the increased bleeding risk acceptable. They reanalyzed the data using 3 different models of risk and they introduced the novel concept of the “number willing to treat” (NWT). The NWT is a hypothetical construct: the number of patients a doctor would be willing to put on aspirin given the known benefits and risks. If the NWT was low, it means that the risks probably outweigh benefits (the doctor isn’t willing to put a lot of people on aspirin).

They found that only age correlated with benefit—the older the woman was, the more benefit she could derive. Other risk factors didn’t matter. But the benefits never seemed to outweigh the risks no matter how the data were analyzed. The authors conclude that, at least in this relatively healthy cohort of women, the risks of aspirin are prohibitive. Randomized trials of higher risk women are still ongoing, so the case probably isn’t closed yet.

Changing gears, heart failure is an American scourge, accounting for more hospitalizations and costs than any other diagnosis. Mortality is high, especially with advanced cases, and smoking hastens death. But what about secondhand smoke (SHS)? Investigators at the University of California at San Francisco surveyed 204 nonsmoking heart failure patients on their exposure to SHS and assessed their quality of life and functional status. Exposure was defined via a questionnaire and urinary cotinine levels (cotinine is a metabolite of nicotine). Patients then took a validated survey on well being, and some also participated in a 6-minute walk test to assess their functional status. At baseline, patients with and without exposure to SHS were well matched. After adjustment for other factors, patients with exposure had poorer perceptions of their quality of life and did worse on the 6-minute walk. The effects appeared dose related, although they were apparent even at the lowest levels of exposure. The take home message is not surprising: smoking is a significant health risk, even among individuals who are not lighting up.

FURTHER READING

Dorresteijn JAN, Visseren1 FLJ, Ridker PM, et al. Aspirin for primary prevention of vascular events in women: individualized prediction of treatment effects. European Heart Journal 2011; 32: 2962–2969.

 

Weeks SG, Glantz SA, De Marco T, et al. Secondhand smoke exposure and quality of life in patients with heart failure. Arch Intern Med. 2011; 171:1887-1893.

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