Brief Report: Alternative Pulmonary Function Measures of Emphysema in People With HIV.

Introduction: People with HIV (PWH) have nearly twice the risk of emphysema than people without HIV. This risk, which has been associated with HIV-mediated changes in the lung immune environment and more extensive radiographic emphysema, may result in different patterns of airflow limitation on pulmonary function testing (PFT) than those traditionally used in people without HIV.

Methods: In this prospective cohort of PWH in Atlanta, Georgia, we analyzed PFT and chest computed tomography data from July 2013 through June 2018. After comparing the prevalence of PFT measures of airflow limitation for those with and without radiographic emphysema, we used binary recursive partitioning to identify PFT measures that differentiated between PWH with and without radiographic emphysema.

Results: Among 167 PWH who had both PFT and computed tomography data during the study period, 89 (53%) had radiographic emphysema. Those with radiographic emphysema were more likely to have airflow limitations on PFTs. Recursive partitioning identified partitions at a forced expiratory volume in 1 second to forced vital capacity ratio (FEV1/FVC) of 0.78 and a residual volume of 116% predicted. These partitions enabled the identification of 84 (94%) PWH with radiographic emphysema, in contrast to the traditional diagnostic criteria of an FEV1/FVC ratio of 0.7, which only identified 49 (55%) of those with radiographic emphysema.

Conclusions: Emphysema in PWH may have different patterns of airflow limitation on PFTs that are not adequately captured by traditional diagnostic criteria. Future studies can seek to validate these findings and determine optimal thresholds for diagnosing HIV-associated emphysema.