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ART Helps Bring Lungs Up to Par in Nonsmokers, But Not Smokers
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49th ICAAC (Interscience Conference on Antimicrobial Agents and Chemotherapy), September 12-15, 2009, San Francisco
Mark Mascolini
The researchers conclude that "on a lung level, smoking definitely masks many of the beneficial effects of proper HIV treatment."
Signals of early obstructive lung disease in nonsmokers improved over an average 4.5 years of effective antiretroviral therapy (ART) in Denmark [1]. But in smokers one marker of lung function worsened despite a good response to antiretrovirals, and other markers improved only to the point seen in nonsmokers at the first lung-function checkup.
Danish clinicians measured lung function in 63 HIV-infected people in 2000 and 2001, then repeated the tests an average 4.5 years later (range 3.8 to 5.7) between July 2005 and March 2007. These 33 nonsmokers and 30 smokers attended the HIV outpatient clinic at a Copenhagen hospital.
More than 80% of both groups were men, and at the first lung-function visit nonsmokers did not differ significantly from smokers in age (mean 43.3 years overall), CD4 count (mean 520), HIV duration (median 105 months), percentage on antiretrovirals (mean 89%), antiretroviral duration (mean 58 months), viral load below 100 copies (mean 75%), or viral load in people with unsuppressed viremia (median 45,500 copies). Smokers had a significantly lower body mass index (mean 22.6 versus 24.0 kg/m(2), P = 0.040) and a significantly lower systolic blood pressure (mean 124.4 versus 133.1 mm Hg, P = 0.037).
At the follow-up visit, 32% of the group were taking two nucleosides and a nonnucleoside, 27% were taking two nucleosides and one or two protease inhibitors (PIs), 16% were taking one drug from each of the first three classes, 10% were taking three nucleosides and one PI, and the rest were taking other combinations. The most used "third drugs" were efavirenz (37%), lopinavir (16%), saquinavir (16%), and nevirapine (13%). The most-prescribed nucleosides were lamivudine (83%), zidovudine (51%), and abacavir (44%). Only 19% were taking tenofovir at this point, and only 3% were not taking antiretrovirals.
Lung function tests and comparative status at the first visit included:
· FEV1% (forced expired volume in the first second): similar in smokers and nonsmokers
· FVC% (functional vital capacity): similar in smokers and nonsmokers
· PEF% (peak flow): similar in smokers and nonsmokers
· RV% (residual volume): similar in smokers and nonsmokers
· TLC% (total lung capacity): similar in smokers and nonsmokers
· DLCO/VA% (diffusing capacity divided by alveolar volume): reduced in smokers versus nonsmokers
· FEV1%FVC (FEV1 as percentage of FVC): reduced in smokers versus nonsmokers
Between the first and second lung-function visits, neither FEV1% nor PEF% changed in either group. FVC% increased from 100.1% to 104.5% in nonsmokers (P = 0.005) and from 99.5% to 103.1% in smokers (P = 0.023). TLC% decreased from 102.8% to 92.3% in nonsmokers (P < 0.001) and from 101.0% to 93.0% in smokers (P < 0.001). FEV1%FCV fell from 83.0% to 78.3% in nonsmokers (P < 0.001) and from 76.5% to 71.8% in smokers (P < 0.001). DLCO/VA% rose from 80.7% to 100.4% in nonsmokers (P < 0.001) and from 63.8% to 79.3% in smokers (P < 0.001).
RV% was the only measure that went in different directions in nonsmoker and smokers, dropping from 109.9% to 98.3% in nonsmokers (P = 0.004) and climbing from 108.8% to 122.8% in smokers (P = 0.046).
The researchers rate initial lung function findings for the whole group as "somewhat compatible with signs of early obstructive lung disease." At the follow-up visit, DLCO/VA% rose back to normal in nonsmokers, while in smokers it inched back to about the initial point recorded in nonsmokers.
Overall, the investigators think "4.5 years of modern HIV management seemed to reduce the obstructive component observed in the initial examination." But they were surprised by the disparate change in RV%. In nonsmokers that measure fell to normal at the follow-up exam, but among smokers it rose further into the abnormal range. The researchers conclude that "on a lung level, smoking definitely masks many of the beneficial effects of proper HIV treatment."
Reference
1. Kristoffersen US, Lebech A, Gerstoft J, et al. Changes of lung function in an optimally treated HIV population: a 4.5 year follow up study. 49th ICAAC (Interscience Conference on Antimicrobial Agents and Chemotherapy). September 12-15, 2009. San Francisco. Abstract H-1561.
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