Sputum glucose as a marker of disease severity in adult patients with cystic fibrosis

Rationale: In translational medicine the research on systemic and local biomarkers for disease activity in cystic fibrosis (CF) is still an unmet need. Sputum glucose is one of the most promising and it has already been evaluated in different chronic lung diseases. This study aimed to investigate if sputum glucose was associated with clinical markers of lung disease severity in CF adults. Methods: This was an observational, prospective study of consecutive adults with CF enrolled at the Adult CF Center in Milan, Italy, between April and June 2017. Patients with a diagnosis of CF according to last guidelines underwent glucose evaluation on sputum during stable state and demographics, clinical and microbiological data were collected. Sputum glucose assay uses the glucose oxidase-peroxide reaction for the determination of glucose concentrations. CF-related diabetes (CFRD) was evaluated as a confounder through stratification. Results: A total of 28 patients (median age 33 years; females 64%) were enrolled; median BMI was 22, median FEV1 %predict was 76% and 29% had CFRD. Glucose was identified in sputum of all patients with a median level of 13.36 uM (6.72-24.09). Sputum glucose was significantly higher in patients with 3+ exacerbation (PEx)/year in comparison to those with no PEx (P Conclusion: Sputum glucose seems to act as a biomarker of disease severity which may complement patient clinical assessment and be a target for treatment.