Vitamin D deficiency and severity of non-cystic fibrosis bronchiectasis: a systematic review.

Introduction: Vitamin D deficiency is common in cystic fibrosis (CF) and may be linked to disease severity. We aimed to investigate the association between vitamin D deficiency and severity in non-CF bronchiectasis.

Methods: A systematic search of PubMed and Scopus (up to December 2024) identified relevant studies. After screening 170 articles, seven met the inclusion criteria. Study quality was assessed using NIH tools.

Results: Patients with non-CF bronchiectasis had significantly lower serum 25-hydroxyvitamin D (25OHD) levels compared to healthy controls. In one study, median 25OHD was 24.7 nmol/L in patients vs. 45.3 nmol/L in controls. Another reported mean levels of 14.7 ± 9.6 ng/mL vs. 19.8 ± 6.9 ng/mL, respectively. Disease severity was assessed using validated and semi-structured measures, including the bronchiectasis severity index (BSI), number of exacerbations, pulmonary function tests (PFTs), radiological scores (Bhalla, modified Reiff), and health-related quality-of-life (HRQL) tools. Most studies reported worse severity outcomes in vitamin D-deficient patients.

Conclusions: Although vitamin D deficiency appears to be associated with more severe non-CF bronchiectasis, heterogeneity between studies limits definitive conclusions. Future studies should incorporate standardized tools such as the eFACED score to better characterize disease severity.