Jim Kling

March 12, 2012

March 12, 2012 (Seattle, Washington) — Advanced and uncontrolled HIV disease is associated with a decline in lung function more rapid than that seen in smokers, according to a study presented here at the 19th Conference on Retroviruses and Opportunistic Infections.

Previous research has suggested a link between HIV and obstructive lung disease (OLD), which can include asthma and chronic obstructive pulmonary disease. For example, a serum HIV viral load higher than 200,000 copies/mL is associated with a 3.4-fold increase in risk for OLD, according to Michael Drummond, MD, assistant professor of medicine at Johns Hopkins University, Baltimore, Maryland.

To determine the impact of HIV infection on lung function over time, the researchers analyzed participants in the Intravenous Experience (ALIVE) study, which is an observational cohort of 4138 HIV-positive and HIV-negative injection drug users in Baltimore. The team analyzed semiannual clinical, laboratory, and spirometric data.

Lung function was measured using forced expiratory volume in 1 second (FEV1). A volume reduction on this test is indicative of OLD.

The investigators obtained 4555 FEV1 measurements from 1064 HIV-infected participants over a median observation period of 2.75 years. The mean age of the cohort was 49 ± 7 years. Overall, 65% of the patients were male, 91% were black, 30% were HIV-positive, and 94% were current or former smokers.

OLD was detected in 16% of patients; there was no significant difference with respect to HIV status. After adjustment for age, sex, race, body mass index, and smoking pattern, the researchers found that HIV-positive subjects had a reduction in absolute FEV1 of 174 mL, compared with HIV-negative subjects (P < .01).

FEV1 declined in HIV-negative subjects at the rate of 23.6 mL/year; this was not significantly different from the decline seen in HIV-positive subjects with an undetectable HIV RNA viral load (35.7 mL/year; P = .06) or with a viral load of 400 to 75,000 copies/mL (29.9 mL/year).

Subjects with an HIV RNA viral load above 75,000 copies/mL experienced a greater annual FEV1 decline than the other groups (99.1 mL/year; P < .01), a relation that remained even after adjustment for antiretroviral therapy.

Subjects with CD4 counts from 100 to 199 cells/mm3 had a more rapid decline in FEV1 (P = .03) than HIV-negative subjects, as did those with CD4 counts below 100 cells/mm3 (P < .01). Subjects with CD4 counts from 100 to 199 cells/mm3 had a more rapid decline in FEV1 than those with CD4 counts of 200 cells/mm3 or higher (P = .05), as did those with CD4 counts below 100 cells/mm3 (P < .01).

"The markers of advanced and uncontrolled HIV infection increase the risk of breathing test abnormalities that are consistent with OLD, and appear to exceed the effect of cigarette smoking," Dr. Drummond said in a press conference.

The study showed an effect on reduced lung function regardless of smoking habits, which has a confounding effect because there is a high prevalence of smoking among people with HIV. "Those with HIV should be specifically counseled on the importance of smoking cessation," Dr. Drummond said.

The link between poorly controlled HIV and lung function decline makes sense because infections can damage lung tissue and the immune system plays a role in the repair of damaged tissue, according to Andrew Carr, MD, PhD, an immunologist at the University of New South Wales, Australia, who attended the conference.

"As the old saying goes: If you don't take the temp, you can't find a fever. We've been very good at exposing some things that are obvious, but [some associations] are less obvious," Dr. Carr told Medscape Medical News.

Dr. Drummond and Dr. Carr have disclosed no relevant financial relationships.

19th Conference on Retroviruses and Opportunistic Infections (CROI): Abstract 126LB. Presented March 7, 2012.

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