Contributors to diffusion impairment in HIV-infected persons

Area of Science:

• Pulmonary Medicine
• Infectious Diseases
• Cardiovascular Medicine

Background:

• Abnormal diffusing capacity is prevalent in individuals with HIV, even among non-smokers.
• The underlying causes of impaired lung diffusing capacity in HIV are not fully understood, particularly in those who have never smoked.

Purpose of the Study:

• To investigate associations between lung diffusing capacity for carbon monoxide (D(LCO)) % predicted and various clinical, radiological, and inflammatory markers in HIV-infected individuals.
• To stratify these associations based on smoking history (ever-smokers vs. never-smokers).

Main Methods:

• Cross-sectional analysis of 158 HIV-infected individuals without acute respiratory symptoms.
• Assessed D(LCO) % predicted, spirometry (FEV1, FEV1/FVC), radiographic emphysema, cardiovascular markers (TRVJ, NT-proBNP), and sputum cell counts.
• Stratified analyses by smoking history.

Main Results:

• Overall, 34.8% of participants had significantly reduced D(LCO) (<60% predicted).
• In ever-smokers, lower D(LCO) correlated with lower FEV1 % predicted and increased radiographic emphysema.
• In never-smokers, D(LCO) correlated with FEV1, sputum neutrophils, and sputum lymphocytes, but not radiographic emphysema.

Conclusions:

• Airway obstruction, emphysema, and inflammation are key factors influencing D(LCO) in HIV.
• Never-smokers with HIV may exhibit a distinct pattern of diffusing capacity impairment.
• A multifactorial interplay likely contributes to widespread diffusing capacity abnormalities in HIV infection.