Rates and Risk Factors of Progression in Patients with Nontuberculous Mycobacterial Pulmonary Disease: Secondary Analysis of a Prospective Cohort Study

BackgroundThe clinical course of nontuberculous mycobacterial pulmonary disease (NTM-PD) is varied, and a watchful waiting management strategy is appropriate for a subset of patients. Understanding disease progression and risk factors for progression is essential for deciding on an appropriate follow-up strategy.Research QuestionWhat is the rate of NTM-PD progression, and what are the predictors of progression?Study Design and MethodsPatients with NTM-PD who were enrolled in a prospective observational cohort study between July 1, 2011, and December 31, 2022 were included in this analysis. Clinical, bacterial, laboratory, and radiographic data were collected at enrollment and then regularly during follow-up. NTM-PD progression was defined as either the initiation of treatment or the clinician’s intention to treat. The rate of progression was calculated and the predictors for progression were analyzed.ResultsOf the 477 patients enrolled, NTM-PD progressed in 192 patients over a median follow-up of 5.4 years. The incidence of NTM-PD progression was 11.0 cases per 100 person-years (95% confidence interval [CI] 9.5–12.7). The proportion of patients experiencing disease progression was 21.4% at 1 year, 33.8% at 3 years, and 43.3% at 5 years. The final multivariable analysis model identified female sex (adjusted hazard ratio [aHR] 1.69, 95% CI 1.19–2.39), elevated erythrocyte sedimentation rate (aHR 1.79, 95% CI 1.31–2.43), percent predicted forced expiratory volume in 1 second (aHR 0.89, 95% CI 0.82–0.96), and the presence of a cavity (aHR 2.78, 95% CI 2.03–3.80) as predictors of progression.InterpretationAbout half of patients with NTM-PD experienced progression during an observation period of more than 5 years. Patients with risk factors for progression should be observed closely.Trial registrationClinicalTrials.gov; No.: NCT01616745; URL: www.clinicaltrials.gov