Identifying Metabolomic Biomarkers of Lung Function Decline in People with HIV.

Background: Pulmonary complications in people living with HIV (PWH) have shifted away from infectious disease and towards chronic disease. HIV is an independent risk factor for chronic obstructive pulmonary disease (COPD), with PWH developing COPD younger and declining faster in pulmonary function. As an accelerated decline is associated with greater mortality, there is a need to identify individuals at high risk of longitudinal decline.

Setting: 59 adults with HIV enrolled from the Pittsburgh Lung HIV study cohort.

Methods: Targeted metabolite profiling was performed on baseline bronchoalveolar lavage fluid (BALF, n=35) and serum samples (n=54) using liquid chromatography-high resolution mass spectrometry. Longitudinal pulmonary function tests (median 3 measurements over 2.95 years with a follow-up interval of 1.34 years) were used to determine rates of decline. Predictive modeling and feature selection algorithms identified baseline clinical and metabolomic factors associated with longitudinal decline across forced expiratory volume, forced vital capacity, and diffusing capacity of the lung.

Results: Predictive models found the BALF metabolome to successfully predict outcomes more consistently than serum. Key BALF metabolites such as elevated carnitine and reduced pyruvate predicted greater risk of longitudinal decline. Low serum citrate levels were a robust predictor of decline across multiple tests. Probabilistic graphical models supported direct relationships between these metabolites and lung function decline.

Conclusion: Baseline metabolomic profiling, especially using BALF, can help identify PWH at risk for accelerated lung function decline. Key metabolic pathways related to glucose oxidation, fatty acid metabolism, and amino acid metabolism underlie observed lung function changes.