BACKGROUND: The incidence of Mycobacterium kansasii pulmonary disease (MK-PD) was increasing worldwide. However, limited research was conducted on how to improve the cure rate and evaluate treatment efficacy for patients. We aimed to identify key factors that could improve the cure rate in patients with MK-PD. METHODS: In this retrospective cohort study, the medical records of patients with MK-PD, registered with Shanghai Pulmonary Hospital between January 2016 and December 2020, were collected. These included data on demographics, as well as clinical, radiological, microbiological, drug resistance, and drug regimen information, and treatment outcomes. Multivariate logistic regression analysis was conducted to identify risk factors for treatment failure in patients. RESULTS: This study included 129 patients, of whom 100 (77.5 %) were treated successfully. Logistic regression analysis identified non-absorption of pulmonary cavities as an independent risk factor for treatment successful (odds ratio: 7.9, 95 %confidence interval: 1.7-36.2, p = 0.008). The overall cure rate for patients with absorption of pulmonary cavities (APC) was 93 %
55 % of patients began resorption within 6 months of the start of treatment (the cure rate was 95 %). The APC rate of patients with MK-PD negatively correlated with the number of comorbidities (p = 0.009)
that was, the more comorbidities, the more difficult the cavity absorption and the lower the cure rate. CONCLUSIONS: The absorption of pulmonary cavities was the key to the cure rate for patients with MK-PD. Early changes in cavities helped identify the effect of treatment and guide doctors in optimizing treatment plans to improve patient cure rates.