HIV and Smoking a Lethal Combo for the Lungs
Lifesaving antiretroviral drugs have improved life expectancy to the point that patients now have more to fear from tobacco than HIV, said lead researcher Dr. Krishna Reddy.
"Thanks to antiretroviral medicines, people with HIV are living longer," said Reddy, a pulmonologist and critical care doctor with Massachusetts General Hospital in Boston. "The bad news is that they're living long enough to get cancer."
Based on the new findings, smoking cessation should be a focus of treatment, he and his colleagues said.
More than 40 percent of people with HIV are smokers, a rate more than double that of the general population, Reddy said.
Fatalism and depression among HIV patients often lead them to take up the habit, even though the threat of HIV has decreased significantly for those who take their medication as prescribed, Reddy said.
An evidence review published in The Lancet in May found that HIV patients on antiretroviral therapy stand an excellent chance of reaching old age. For example, average 20-year-olds starting treatment today will live into their mid-60s, the review found.
"In the past, most people didn't live long enough to face the consequences of smoking. Smoking wasn't commonly thought of as a threat to their health," Reddy said. "Unfortunately, there is still a feeling among people with HIV that, 'well, I have HIV, that's what is going to kill me, it doesn't matter if I smoke.'"
Reddy and his colleagues created a computer model to project the risk of lung cancer among people with HIV, taking into account whether they are current or former smokers and how many cigarettes a day they smoke.
Prior studies have shown that HIV infection increases the risk of lung cancer separate from smoking, Reddy said.
Tobacco smoke and HIV both promote inflammation and infections in the lungs, which increase cancer risk. "You put those two together and the risk becomes very high," Reddy said.
The research team found that nearly 25 percent of HIV patients who take their medication but continue to smoke will die from lung cancer. Heavy smokers are at even greater risk, with about 30 percent dying from lung cancer.
Overall, people with HIV who smoke and adhere to their drug regimen are 6 to 13 times more likely to die from lung cancer than HIV/AIDS, depending on how intensely they smoke and whether they are male or female, the researchers reported.
"It turns out that lung cancer is now one of the leading causes of death for people with HIV, particularly among those who are on treatment," Reddy said.
Quitting can drastically alter those odds, researchers found. Only about 8 percent of heavy smokers who quit by age 40 are expected to die from lung cancer, and the odds are even better for moderate and light smokers, the researchers said.
The computer model "makes a very strong case for increased smoking cessation efforts in centers that treat people infected with HIV," said Dr. Norman Edelman, senior scientific advisor for the American Lung Association.
"I think that clinics and centers that take care of patients with HIV should add smoking cessation to their toolbox," Edelman said. "It's just as important as making sure they eat right and are protected from infections by other agents."
Patients and doctors need to adopt a new view of HIV's relative risks in the face of medical breakthroughs, Reddy said.
"Smoking isn't very high on the radar when it comes to people with HIV," Reddy said. "It's often lower down on the priority list, when, in fact, today for a person with HIV who's on treatment the No. 1 cause of death isn't the virus. It's smoking."
The new study was published Sept. 18 in JAMA Internal Medicine.
For more on smoking and HIV, visit the U.S. Department of Health and Human Services.
Posted: September 2017
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