Cigarette smoking substantially reduces the lifespan of people living with HIV in the US, potentially even more than HIV itself.
“A person with HIV who consistently takes anti-HIV medicines but smokes is much more likely to die of a smoking-related disease than of HIV,” says Dr Krishna Reddy, of theMassachusetts General Hospital (MGH) division of pulmonary and critical care medicine and the Medical Practice Evaluation Centre, who led the study. “The good news is that quitting smoking can greatly increase lifespan, and it is never too late to quit.”
While only 15% of the general US adult population smokes cigarettes, among people living with HIV the smoking rate is over 40%, and an additional 20% are former smokers. The widespread use of antiviral medications today allows people with HIV to live longer, but smokers with HIV are developing smoking-related diseases – such as lung cancer, heart disease, and chronic obstructive pulmonary disease (COPD, sometimes referred to as emphysema) – at higher rates than are HIV-uninfected individuals.
The researchers used epidemiologic data to estimate the average lifespans of people living with HIV depending on whether they were current, former or never smokers. Extending a validated simulation model of HIV developed by the team, they demonstrated that a person with HIV could lose more than 8 years of life simply because of his or her smoking habits and unrelated to HIV infection. They also found that, if one-quarter of the people receiving care for HIV in the US who smoke were to quit now, more than a quarter million years of life would be saved.
The study found that for a 40-year-old person who receives care for HIV but – as is often the case in the US – does not perfectly follow recommended treatment, smoking shortens his or her expected lifespan by more than 6 years, compared with a non-smoker who is similarly not perfectly adherent to antiviral treatment. For someone who adheres well to anti-HIV medicines, smoking shortens his or her expected lifespan by more than 8 years – about double the impact of HIV itself – compared with a non-smoker who perfectly adheres to treatment. For those who are smokers when they enter treatment for HIV, quitting smoking, particularly at younger ages, was shown to reverse much of the loss of life expectancy.
“Smoking cessation should be a key part of the care of people living with HIV to improve both their lifespan and their quality of life,” says study co-author Dr Travis Baggett, MPH, of the MGH division of general internal medicine division and the Tobacco Research and Treatment Centre.
Dr Rochelle Walensky, of the MGH division of infectious diseases, senior author of the study, says, “It is time to recognise that smoking is now the primary killer of people with HIV who are receiving treatment.”
Reddy adds, “Unfortunately, smoking cessation interventions have not been widely incorporated into HIV care. Given how common smoking is among people with HIV, now is the time to change that.” Reddy is an instructor in medicine, Baggett is an assistant professor of medicine and Walensky is a professor of medicine at Harvard Medical School.
Additional co-authors are Dr Robert Parker, DrNancy Rigotti and Dr Kenneth Freedberg, MGH division of general internal medicine; Dr Elena Losina, Brigham and Women’s Hospital; Dr David Paltiel, Yale School of Public Health; and Dr Milton Weinstein, Harvard TH Chan School of Public Health.
Background: In the United States, >40% of people infected with human immunodeficiency virus (HIV) smoke cigarettes.
Methods: We used a computer simulation of HIV disease and treatment to project the life expectancy of HIV-infected persons, based on smoking status. We used age- and sex-specific data on mortality, stratified by smoking status. The ratio of the non-AIDS-related mortality risk for current smokers versus that for never smokers was 2.8, and the ratio for former smokers versus never smokers was 1.0–1.8, depending on cessation age. Projected survival was based on smoking status, sex, and initial age. We also estimated the total potential life-years gained if a proportion of the approximately 248 000 HIV-infected US smokers quit smoking.
Results: Men and women entering HIV care at age 40 years (mean CD4+ T-cell count, 360 cells/µL) who continued to smoke lost 6.7 years and 6.3 years of life expectancy, respectively, compared with never smokers; those who quit smoking upon entering care regained 5.7 years and 4.6 years, respectively. Factors associated with greater benefits from smoking cessation included younger age, higher initial CD4+ T-cell count, and complete adherence to antiretroviral therapy. Smoking cessation by 10%–25% of HIV-infected smokers could save approximately 106 000–265 000 years of life.
Conclusions: HIV-infected US smokers aged 40 years lose >6 years of life expectancy from smoking, possibly outweighing the loss from HIV infection itself. Smoking cessation should become a priority in HIV treatment programs.
Krishna P Reddy, Robert A Parker, Elena Losina, Travis P Baggett, A David Paltiel, Nancy A Rigotti, Milton C Weinstein, Kenneth A Freedberg, Rochelle P Walensky