HIV Infection and Emphysema

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The summary below is from the full report titled "Increased Susceptibility to Pulmonary Emphysema among HIV-Seropositive Smokers.". It is in the 7 March 2000 issue of Annals of Internal Medicine (volume 132, pages 369-372). The authors are P.T. Diaz, M.A. King, E.R. Pacht, M.D. Wewers, J.E. Gadek, H.N. Nagaraja, J. Drake, and T.L. Clanton.

What is the problem and what is known about it so far?

Emphysema is a condition in which the bronchial tubes and lungs become damaged over time, resulting in shortness of breath. Smoking is nearly always the main cause of emphysema. Emphysema usually does not develop until people are in their 50s or 60s. An accelerated form of emphysema has been reported in some young persons infected with the human immunodeficiency virus (HIV), which is the virus that causes AIDS. However, those reports did not compare persons infected with HIV directly with persons without HIV infection.

Why did the researchers do this particular study?

The researchers wanted to see whether persons with HIV infection, particularly those who smoke, are at greater risk for emphysema than persons, including smokers, without HIV infection.

Who was studied?

The study included 114 persons with HIV infection. The comparison group included 44 people without HIV infection who were of similar age and who had similar smoking habits as the persons with HIV infection.

How was the study done?

All of the people in the study had special, highly sensitive CT scans of their chests to look for evidence of emphysema. They also underwent a procedure called bronchoalveolar lavage in which doctors insert a small tube down into the airways that lead to the lungs (bronchial tubes) and take specimens of washings that contain cells and fluid.

What did the researchers find?

Only 2% of the persons without HIV infection had emphysema, whereas 15% of the persons with HIV infection had this condition. Among HIV infected persons who had smoked the equivalent of a pack of cigarettes per day for 12 or more years, 37% had emphysema compared to 0% in the comparison group who had smoked a pack per day for this length of time. The researchers also found higher levels of certain immune cells in the airway fluids of people with HIV infection than they did in the comparison group.

What were the limitations of the study?

The study included a relatively small number of people, especially in the comparison group. The presence of immune cells in the airway fluid suggests that HIV may play a role in the development of emphysema but does not prove that it does.

What are the implications of the study?

HIV infection may accelerate the development of emphysema associated with smoking. HIV-infected smokers should consider this as a further reason to avoid smoking.