People with HIV on effective antiretroviral treatment who smoke cigarettes may incur more risk of death and reduction in life expectancy from smoking than from HIV/AIDS-related conditions, according to a study described in the November 3 advance edition of the Journal of Infectious Diseases.
“A person with HIV who consistently takes HIV medicines but smokes is much more likely to die of a smoking-related disease than of HIV itself,” lead author Krishna Reddy from the Medical Practice Evaluation Center at Massachusetts General Hospitalsaid in an Infectious Diseases Society of America press release.
As people with HIV live longer thanks to the advent of effective combination antiretroviral therapy (ART) that keeps viral replication under control and CD4 cell counts high, chronic non-HIV/AIDS conditions such as cardiovascular disease and cancer are a growing concern. Ongoing inflammation and immune activation play a role, but HIV-positive people are also more likely to have other risk factors such as smoking.
In the U.S. it is thought that more than 40% of people living with HIV smoke cigarettes — more than twice the rate of the population as a whole — which translates to over 247, 500 smokers in HIV care.
Reddy and colleagues used a computer simulation model of HIV disease progression and treatment, along with age- and sex-specific mortality data, to predict the life expectancy of HIV-positive people based on smoking status.
- The ratio of non-AIDS-related mortality risk for current smokers versus those who never smoked was 2.8, or nearly 3 times higher.
- The ratio for former smokers versus those who never smoked ranged from 1.0 to 1.8, depending on age at the time of smoking cessation.
- Men and women starting HIV care at age 40 with a mean CD4 count of 360 cells/mm3 who continued to smoke lost 6.7 and 6.3 years of life expectancy, respectively, compared to those who never smoked.
- Among people who maintained excellent adherence to HIV treatment, smoking reduced life expectancy by about twice as much as HIV/AIDS (8.6 vs 3.5 years for men and 8.2 vs 4.3 years for women).
- Among people with lower adherence and missed follow-up care — typical of real-world HIV care in the U.S. — life expectancy lost to smoking was similar to that lost to HIV/AIDS, especially for men (6.7 vs 6.9 years for men and 6.3 vs 8.3 years for women).
- However, men who quit smoking when they started HIV care at age 40 regained 5.7 years and women regained 4.6 years.
- Factors associated with greater benefits from smoking cessation included younger age, higher baseline CD4 count, and complete ART adherence.
The study authors estimated that if 10% to 25% of HIV-positive smokers in the U.S. gave up smoking, they could collectively save approximately 106,000 to 265,000 years of lost life.
“HIV-infected U.S. smokers aged 40 years lose >6 years of life expectancy from smoking, possibly outweighing the loss from HIV infection itself,” the researchers concluded.
“Providers caring for HIV-infected people should address smoking during every patient encounter and offer guideline-based behavioral and pharmacologic treatments for tobacco use,” they recommended. “Novel intervention strategies targeting this important population are needed. Smoking cessation should be a major priority in HIV care programs.”
“This study makes clear that we must prioritize smoking cessation among adults with HIV if we want them to have an increase in the quantity (and likely quality) of life,” Keri Althoff from Johns Hopkins Bloomberg School of Public Health wrote in an accompanying editorial. “By showing that smoking cessation results in a greater gain in life expectancy than ART initiation at higher CD4+ T-cell counts or improved adherence to ART, there should be renewed urgency to implement smoking cessation programs, thereby continuing to shift the paradigm of HIV care to the increasingly important prevention of comorbidities after ART initiation.”
“Now that HIV-specific medicines are so effective against the virus itself, we also need to add other interventions that could improve and extend the lives of people with HIV,” Reddy concurred. “We show that even people who have been smoking till age 60 but quit at age 60 have a substantial increase in their life expectancy. So it’s never too late to quit.”
By Liz Highleyman
KP Reddy, RA Parker, E Losina, R Walensky, et al. Impact of Cigarette Smoking and Smoking Cessation on Life Expectancy Among People With HIV: A US-Based Modeling Study. Journal of Infectious Diseases. November 3, 2016 (online ahead of print).
KN Althoff. The Shifting Paradigm of Care for Adults Living With HIV: Smoking Cessation for Longer Life. Journal of Infectious Diseases. November 3, 2016 (online ahead of print).
Infectious Diseases Society of America. For Smokers with HIV, Smoking May Now Be More Harmful than HIV Itself. Press release. November 3, 2016.
Massachusetts General Hospital. Smoking may shorten the lifespan of people living with HIV more than HIV itself. Press release. November 3, 2016.