Characteristics associated with progression in patients with of nontuberculous mycobacterial lung disease : a prospective cohort study

BACKGROUND Patients with distinctive morphotype were more susceptible to nontuberculous mycobacterial lung disease (NTM-LD). However, little is known about the association between body morphotype and progression of NTM-LD. The aim of this study was to elucidate predictors of NTM-LD progression, focusing on body morphotype and composition. METHODS Data from patients with NTM-LD who participated in NTM cohort which started in 1 July 2011 were analyzed. Patients with more than 6 months of follow up were included for analysis. NTM-LD progression was defined as clinician-initiated anti-NTM treatment, based on symptomatic and radiologic aggravation. Body morphotype and composition was measured at entry to the cohort using bioelectrical impedance analysis. RESULTS NTM-LD progressed in 47 out of 150 patients with more than 6 months of follow up. Patients with middle (adjusted hazard ratio [aHR], 2.758; 95% confidence interval [CI], 1.112-6.843) or lowest tertile (aHR, 3.084; 95% CI, 1.241-7.668) of abdominal fat ratio had a higher risk of disease progression compared with the highest tertile. Other predictors for disease progression were presence of cavity on chest computed tomography (aHR, 4.577; 95% CI, 2.364-8.861), and serum albumin level <3.5 g/dL (aHR, 12.943; 95% CI, 2.588-64.718). CONCLUSIONS Progression of NTM-LD is associated with body composition. Lower abdominal fat ratio is an independent predictor of NTM-LD progression. TRIAL REGISTRATION ClinicalTrials.gov, NCT01616745 Registered 25 March 2012.