The breath print represents a novel biomarker of malnutrition in pulmonary arterial hypertension: A proof of concept study.

Background The breath print is a quantitative measurement of molecules in exhaled breath and represents a new frontier for biomarker identification. It is unknown whether this state-of-the-art, noninvasive method can detect malnutrition. We hypothesize that individuals with malnutrition will present with a distinguishable breath print. Methods We conducted a retrospective chart review on patients with previously analyzed breath samples to identify malnutrition. Breath was analyzed by selected-ion flow-tube mass spectrometry. Registered dietitians conducted a retrospective chart review to collect malnutrition diagnosis and nutritional status indicators. Patients were categorized into one of four groups: pulmonary arterial hypertension (PAH), PAH with malnutrition (PAH-Mal), Control, and Control with malnutrition, based on malnutrition diagnosis present in the patient's chart. Principle component analysis was conducted to characterize the breath print. A logistic regression model with forward selection was used to detect the best breath predictor combination of malnutrition. Results 74 subjects met inclusion criteria (PAH:52; PAH-Mal:10; Control:10; Control-Mal:2). 1-octene (PAH-Mal 5.1±1.2, PAH 12.5±11.2; p = 0.005) and ammonia (PAH-Mal 14.6±15.8, PAH 56.2±64.2; p = 0.013) were reduced in PAH-Mal compared to PAH. The combination of 1-octene (p = 0.010) and 3-methylhexane (p = 0.045) distinguished malnutrition in PAH (ROC AUC: 0.8549). Conclusions This proof-of-concept study provides the first evidence that the breath print is altered in malnutrition. Larger, prospective studies are needed to validate these results and establish whether breath analysis may be a useful tool to screen for malnutrition in the clinical setting. Clinical relevancy statement Early identification and intervention combats malnutrition. However, malnutrition screening practices are hindered by a lack of a malnutrition biomarker. The breath print describes the molecules released in the exhaled breath and is a novel "tissue" to identify biomarkers of disease. This report identifies that the breath print is altered in patients with malnutrition and implicates potential for its use as a malnutrition screening biomarker. This article is protected by copyright. All rights reserved.