Association Between CD4, Viral Load, and Pulmonary Function in HIV.

Purpose: The antiretroviral therapy era has shifted the epidemiology of HIV-associated diseases, increasing the recognition of non-infectious pulmonary complications secondary to HIV. We aimed to determine the association between CD4, viral load, and pulmonary function in individuals with uncontrolled HIV, and determine how changes in these parameters are associated with pulmonary function longitudinally.

Methods: This is a retrospective observational study of individuals with HIV who underwent pulmonary function testing in an urban medical center between August 1997 and November 2015.

Results: Of the 146 participants (mean age 52 ± 10 years), 49% were Hispanic, 56% were men, and 44% were current smokers. CD4 <200 cells/μl was associated with significant diffusion impairment compared to CD4 ≥200 cells/μl (DL 56 vs. 70%, p = <0.01). VL (viral load) ≥75 copies/ml was associated with significant diffusion impairment compared to VL <75 copies/ml (DL 60 vs. 71%, p = <0.01). No difference in FEV1, FEV1/FVC, or TLC was noted between groups. In univariate analysis, CD4 and VL correlated with DL (r = +0.33; p = <0.01; r = -0.26; p = <0.01) and no correlation was noted with FEV, FEV/FVC, or TLC. Current smoking and history of AIDS correlated with DL (r = -0.20; p = 0.03; r = -0.20; p = 0.04). After adjusting for smoking and other confounders, VL ≥75 copies/ml correlated with a 11.2 (CI 95% [3.03-19.4], p = <0.01) decrease in DL. In Spearman's Rank correlation, there was a negative correlation between change in VL and change in DL over time (ρ = -0.47; p = <0.01).

Conclusion: The presence of viremia in individuals with HIV is independently associated with impaired DL. Suppression of VL may allow for recovery in diffusing capacity over time, though the degree to which this occurs requires further investigation.