Clinical value of sputum galactomannan testing in the diagnosis of invasive pulmonary aspergillosis among chronic obstructive pulmonary disease patients.

Abstract

Background: Diagnosing invasive pulmonary aspergillosis (IPA) in patients with chronic obstructive pulmonary disease (COPD) remains challenging due to the non-specific nature of imaging findings, the limited sensitivity of current diagnostic methods, and the difficulty of obtaining appropriate clinical specimens.

Objective: To evaluate the diagnostic accuracy of sputum galactomannan (GM) testing in COPD patients with IPA.

Methods: In this multicenter cross-sectional study, COPD patients with suspected IPA and patients with community-acquired pneumonia (CAP) were enrolled. GM testing was performed on sputum, serum, and bronchoalveolar lavage fluid (BALF) samples, while fungal culture was conducted on sputum samples. Diagnostic performance was assessed using the EORTC/MSGERC criteria as the reference standard.

Results: A total of 134 patients were included, comprising the COPD + IPA group (n = 43), the COPD + CAP group (n = 70), and the CAP group (n = 21). The areas under the receiver operating characteristic curve (AUCs) for GM detection in sputum, BALF, and serum were 0.833 (95% CI: 0.753-0.913), 0.884 (95% CI: 0.799-0.970), and 0.659 (95% CI: 0.552-0.766), respectively. The optimal cut-off values for sputum and BALF GM were 1.64 and 1.12, respectively. At these thresholds, sputum GM demonstrated a sensitivity of 79.1% and specificity of 75.7%, while BALF GM showed a sensitivity of 76.5% and specificity of 96.6%.

Conclusion: Sputum GM testing demonstrates significant diagnostic value for IPA in COPD patients and provides a non-invasive alternative with reliable performance, making it a promising tool for preliminary screening and reducing the need for invasive procedures in clinical practice.

The clinical trial registration number: ChiCTR2400089800.