To determine whether the higher rate
of lung cancer seen among HIV patients is due to biological effects of HIV,
surveillance bias or excess smoking, the research team compared the incidence
of lung cancer between patients with HIV and demographically similar but
HIV-negative patients, accounting for smoking and lung cancer stage at
diagnosis. An analytic cohort of 37,294 HIV-infected patients and 75,750
uninfected patients was created by linking data from the Veterans Aging Cohort
Study Virtual Cohort and data from the Veterans Affairs Central Cancer
Registry.
The incidence rates of
pathologically confirmed lung cancer were calculated by dividing numbers of
cases by numbers of person-years at risk. Incidence rate ratios (IRRs) -
adjusted for age, sex, race/ethnicity, smoking prevalence, previous bacterial
pneumonia, and chronic obstructive pulmonary disease - were determined using
Poisson regression.
The results indicated a lung cancer
incidence rate of 204 cases per 100,000 person-years among patients with HIV
(95 percent confidence interval 167-249) and 119 cases per 100,000 person-years
among uninfected patients (95 percent CI 110-129). Lung cancer stage at
presentation did not differ between the two groups; however, the IRR of lung
cancer associated with HIV infection remained significant after multivariable
adjustment (IRR 1.7; 95 percent CI 1.5-1.9).
“In our cohort of demographically
similar HIV-infected and uninfected patients, HIV infection was an independent
risk factor for lung cancer after controlling for potential confounders
including smoking,” the authors concluded. “The similar stage distribution
between the two groups indicated that surveillance bias was an unlikely
explanation for this finding.”
The Friends of AIDS Foundation is
dedicated to enhancing the quality of life for HIV positive individuals and
empowering people to make healthy choices to prevent the spread of the HIV
virus. To learn more about The Friends of AIDS Foundation, please visit: http://www.friendsofaids.org.
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