Impact of Bronchiectasis on Treatment Outcomes in Patients With Nontuberculous Mycobacterial Pulmonary Disease: A 10-Year Retrospective Cohort Study Stratified by Bronchiectasis Severity.

Abstract

Bronchiectasis is the most common comorbidity in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD); however, its influence on treatment outcomes remains insufficiently explored. How does the presence and severity of bronchiectasis affect treatment outcomes in patients with NTM-PD? In this two-phase retrospective cohort study, a historical cohort of 1,587 patients with NTM-PD and a contemporary cohort of 1,095 patients with NTM-PD were included. The Bronchiectasis Severity Index (BSI) was used for severity assessment and stratification of bronchiectasis. Treatment success rates, culture conversion rates, time to culture conversion, and the risk of treatment failure were compared within each cohort among NTM-PD patients without bronchiectasis and those with mild, moderate, or severe bronchiectasis. In both the historical and contemporary cohorts, overall treatment success rates in patients with NTM-PD declined significantly as bronchiectasis severity increased (all P < 0.001). Similarly, overall culture conversion rates decreased significantly, and time to sputum culture conversion was markedly prolonged (log-rank test: all P < 0.001). Among patients with Mycobacterium abscessus-PD, Mycobacterium intracellulare-PD, and Mycobacterium avium-PD, moderate and severe bronchiectasis were independent risk factors for treatment failure (all P < 0.05). For Mycobacterium kansasii-PD, only severe bronchiectasis was a significant risk factor (both cohorts: P < 0.05). Comorbid bronchiectasis adversely affected treatment outcomes in patients with NTM-PD, with progressively worse outcomes observed as its severity increased. The magnitude of this impact varied across different NTM species, highlighting the need for pathogen- and severity-stratified management strategies.