Smoking masks the long-term benefits of HAART on lung function
Simon Collins, HIV i-Base
A poster by Jan Gerstoft and colleagues from Copenhagen University Hospital looked at the interaction between changes in lung function in relation to smoking and HIV treatment.
Between October 2000 and November 2001, 63 HIV-positive patients had initial lung function assessed by a panel of tests (including forced expired volume, functional vital capacity, peak flow, residual volume [RV%] and total capacity and diffusing capacity/alveolar volume [DLCO/VA%]), with follow-up assessments a median of 4.5 years later (range 3.8-4.7 years).
Most participants (87%) were already on HAART at baseline for a median of about five years (range 16-79 months) with all but two on HAART at the follow-up visit (with 85% and 89% of these patients having viral load <100 copies/mL at each time point, respectively).
Some abnormal lung function parameters were present at baseline in both smoking (n=30) and non-smoking (n=33) participants, and some were further reduced in smokers. Specifically, DLCO/VA% was decreased in both groups, with lung function compatible with early obstructive lung disease. At follow-up these levels normalised in non-smokers and improved in smokers to the baseline levels of the non-smoking group. However, results for residual volume, which returned to normal for non-smokers, increased further in the smoking group.
The researchers concluded that this study showed that HAART was beneficial for lung status and that HIV-related changes can reverse over time in non-smokers. However, smoking masks many of these potential benefits.
As most participants had already been on HAART for many several years at baseline, and results were not divided by HAART use and viral load, the study did not quantify the extent and timeline of the benefits due to antiretroviral therapy. Nevertheless, the suggested positive impact of HAART on lung function is important and the results reinforce the importance of smoking cessation.
Ref: Gerstoft J et al. Changes of lung function in an optimally treated HIV population: a 4.5 year follow up study. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract H-1561.