Quantitative computed tomography body composition analysis for risk stratification in bronchiectasis

Nutritional status and sarcopenia are established contributors to morbidity and mortality in chronic respiratory diseases. This study aimed to assess the prevalence and impact of body composition features extracted from computed tomography (CT) in patients with non-CF bronchiectasis. We analysed data from 112 patients. Muscle and subcutaneous fat area and density were assessed by semi-automatic segmentation at the level of the 12th thoracic vertebra using the mediastinal window of routine chest CT scans. Clinical and functional features were compared between patients with and without body composition abnormalities. Associations between CT-derived body composition parameters and clinical outcomes were explored. The majority of patients were female (86/112, 77%) and the median age was 66 years (56–74). Myosteatosis (low muscle density) affected 75 of 112 (66%) patients. Patients with myosteatosis (MSp) were older than those without (wMSp), median age 70 (61–77) vs. 58 (45–69) years (p < 0.001), and had lower FEV1, 81 (69–95) vs. 89 (78–101) % pred. (p = 0.038) and MEF50, 48 (25–66) vs. 61 (44–74) % pred. (p = 0.043). The incidence of non-tuberculous mycobacteria (NTM) pulmonary disease was higher in MSp compared to wMSp (19% vs. 3%; p = 0.043). Muscular density negatively correlated with the Bronchiectasis Severity Index (r = − 0.32; p = 0.012), FACED (r = − 0.38; p = 0.03) and E-FACED (r = − 0.35; p = 0.007) scores. Myosteatosis was not related to gender, radiological extension of bronchiectasis, bacterial colonization or laboratory data. Myosteatosis is highly prevalent in patients with bronchiectasis and is associated with worse airflow obstruction, higher disease severity, and increased frequency of NTM pulmonary disease, independently from BMI. Abnormal body composition as defined by CT assessment may provide clinically relevant information beyond traditional anthropometrics and complement existing severity scores for risk stratification in patients with bronchiectasis.