February 19, 2010

Smoking Cessation Reduces Cardiovascular Disease Risk in HIV

The risk of developing various forms of cardiovascular disease in people living with HIV decreases with time upon stopping cigarette smoking, according to new data from the D:A:D study reported on Thursday, February 18, at the 17th Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco. Though the results may not come as a surprise, they are among the first to show that smoking cessation has a positive affect on the lives of HIV-positive people.

The rate of cigarette smoking is considerably higher among people living with HIV compared with that in the general population. There is no shortage of data proving that smoking cessation drastically reduces the risk of having a heart attack, stroke or other cardiovascular-related health problem—and that quitting also reduces the need for an invasive coronary artery procedure within one to two years. But little is known about the improved odds in people living with HIV who manage to break their cigarette habits.

To explore the positive effects of smoking cessation on cardiovascular health in people living with HIV, Kathy Petoumenos, PhD, of the National Center in HIV Epidemiology and Clinical Research at the University of New South Wales in Sydney and her colleagues analyzed data being collected in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study, involving more than 33,000 HIV-positive people participating in one of 11 cohorts in the United States, Europe and Australia.

The analysis included more than 27,000 HIV-positive people without a history of cardiovascular disease before enrolling in D:A:D and who provided information about their smoking habits. About 25 percent reported never having smoked, whereas 35 percent were smokers and continued to smoke throughout the study. Nearly 20 percent reporting quitting before enrolling in D:A:D, and an additional 25 percent quit smoking at some point during the study.

Petourmenos’s group looked at four cardiovascular disease “events” among their group of non, current and former smokers during the past 10-plus years of D:A:D follow-up: a myocardial infarction (MI), or heart attack; coronary heart disease (CHD), defined as an MI plus invasive coronary artery procedure; cardiovascular disease, defined as CHD plus removal of plaques from the carotid artery or a stroke; or death from any cause.

About three quarters of the participants were men; roughly 50 percent were white; and the average age upon entering D:A:D was 40. Injection drug users were more likely to be current or past smokers than non-smokers. Rates of high blood pressure, elevated cholesterol and triglyceride levels and obesity—all risk factors for heart disease—were similar between current, past and nonsmokers.

Generally speaking, current smokers were almost four times as likely to experience an MI compared with those who have never smoked. Among those who quit before entering D:A:D, the risk compared with those who never smoked remained elevated—a risk increase around 1 and a half times.

As for those who quit smoking while participating in D:A:D, the risk of a heart attack decreased by about a third after one to years and by half after three years.

Similar declines were also observed for rates of other cardiovascular events, though there was still a lingering risk of these events after three years, compared with those who had never smoked. For example, the risk of CVD among patients who stopped smoking during the follow-up period decreased from 132 percent within the first year of stopping to 49 percent after three-plus years since stopping smoking.

Petoumenos also pointed out that ex-smokers, including those who quite before enrolling in D:A:D and those who stopped smoking while participating in the study, faced a higher risk of non-AIDS cancers compared with nonsmokers (17 percent for both smokers who quit before enrolling and while particing in D:A:D versus 10 percent of those who never smoked). This has been a consistent finding of D:A:D over the years and points to a long-lasting effect of cigarette smoking on the overall health and survival of people living with HIV.

In concluding its report, the study authors repeat a message that has so frequently been offered by others: “Smoking cessation efforts should be a priority in the management of HIV-infected individuals.”

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