Decreased Lung Function and All-Cause Mortality in HIV-infected Individuals

Abstract

Rationale: Human immunodeficiency virus (HIV) infection is associated with pulmonary disease and worse lung function, but the relationship of lung function with survival in HIV is unknown.

Objectives: To determine whether lung function is associated with all-cause mortality in HIV-infected individuals.

Methods: HIV-infected participants from cohorts in three locations underwent pre- and post-bronchodilator spirometry and determination of single-breath diffusing capacity of the lung for carbon monoxide (Dl_CO) in 2008-2009, computed tomographic (CT) scanning of the chest for quantitative emphysema and airway measures, and echocardiography for estimated left ventricular systolic and diastolic function and tricuspid regurgitant velocity. Bivariate analysis and multivariable Cox proportional hazards models were used to determine whether decreased lung function was independently associated with increased all-cause mortality. Models were adjusted for covariates including age, sex, body mass index, smoking status, self-reported hepatitis C status, HIV viral levels, CD4⁺ T-cell counts, hemoglobin, antiretroviral therapy, and illicit drug use.

Results: Overall, 396 HIV-infected participants underwent pulmonary function testing. Thirty-two participants (8%) died during a median follow-up period of 69 months. A post-bronchodilator FEV₁-to-FVC ratio less than 0.7 (hazard ratio [HR], 2.47; 95% confidence interval [CI], 1.10-5.58) and a Dl_CO less than 60% (HR, 2.28; 95% CI, 1.08-4.82) were independently associated with worse mortality. Also, hepatitis C (HR, 2.68; 95% CI, 1.22-5.89) and baseline plasma HIV RNA level (HR per ln RNA copies/ml, 1.50; 95% CI, 1.22-1.86) were associated with mortality in HIV-infected participants. The only CT or echocardiographic measure associated with greater mortality in univariate analysis was greater wall thickness of medium-sized airways (HR for wall area percent, 1.08; 95% CI, 1.00-1.18; P = 0.051), but none of the CT or echocardiogram measures were associated with mortality in multivariable analysis.

Conclusions: Airflow obstruction and impaired diffusing capacity appear to be associated with all-cause mortality in HIV-infected persons over an average of 6 years of follow-up. These data highlight the importance of lung dysfunction in HIV-infected persons and should be confirmed in larger cohorts and with extended follow-up periods. Clinical trial registered with www.clinicaltrials.gov (NCT00869544, NCT01326572).

Keywords: HIV; acquired immunodeficiency syndrome; chronic obstructive pulmonary disease.

Figure 1.

(A) Kaplan–Meier survival estimates for post-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV₁/FVC) < 0.7 versus FEV₁/FVC ≥ 0.7 in human immunodeficiency virus (HIV)-infected participants, and (B) Kaplan–Meier survival estimates for single-breath diffusion capacity for carbon monoxide (Dl_CO) < 60% predicted versus Dl_CO ≥ 60% predicted in HIV-infected participants. BD = bronchodilator.