Associations Between Anemia and Obstructive Sleep Apnea in Patients with Cystic and Non-Cystic Bronchiectasis: A Prospective Cross-Sectional Study.

Background: Anemia and obstructive sleep apnea (OSA) are prevalent comorbidities in bronchiectasis and may share overlapping pathophysiological mechanisms. However, their combined impact on clinical outcomes in bronchiectasis remains underexplored. We aimed to investigate the associations between anemia, OSA, and clinical characteristics in patients with bronchiectasis, including cystic fibrosis (CF) and non-CF subtypes. Methods: 70 adults with bronchiectasis (35 CF-related, 35 non-CF) underwent polysomnography. Anemia was defined using standard hemoglobin < 13 g/dL for men and <12 g/dL for women. Clinical, nutritional, and sleep-related variables were assessed, and associations with anemia were evaluated. Results: Anemia was present in 24.3% of participants. Compared to non-anemic patients, those with anemia had significantly higher rates of female sex (38.5% vs. 6.5%, p = 0.002), nutritional problems (47.1% vs. 20.8%, p = 0.034), OSA prevalence (94.1% vs. 54.7%, p = 0.003), and annual hospitalizations (1.41 ± 0.41 vs. 0.43 ± 0.10, p = 0.002). In multivariate analysis, female sex (OR: 12.32; 95% CI: 3.12-45.96; p = 0.002) and OSA (OR: 4.70; 95% CI: 2.67-45.29; p = 0.007) remained independent predictors of anemia. Subgroup analysis showed a significant univariate association between OSA and anemia in CF patients (p = 0.045), while hospitalization frequency was an independent predictor of anemia in non-CF bronchiectasis (p = 0.040). Conclusions: Anemia in bronchiectasis is independently associated with female sex and OSA, with additional exploratory subgroup findings. These findings indicate an association between OSA and anemia within bronchiectasis populations; however, the cross-sectional design precludes conclusions regarding directionality or causality.