Clinical characteristics and treatment outcomes of patients with nontuberculous mycobacterial pulmonary disease in South Gyeongsang Province: A single centre experience

Limited data exists on the clinical characteristics and treatment outcomes of patinets with nontuberculous mycobacterial pulmonary disease(NTM-PD) in South Gyeongsang Province, Korea. This retrospective study at Samsung Changwon Hospital enrolled NTM-PD patients from Jan 2019 to Feb 2023, with follow-up until Dec 31, 2023. Treatment outcomes, defined as three consecutive negative cultures, were assessed at six months of treatment. A total of 496 patients were analysed. The median age was 67 years, and 62% were women. The most common phenotype was the non-cavitary nodular bronchiectatic form(NC-NB)(67%), followed by the cavitary nodular bronchiectatic form(C-NB)(15%), and the fibrocavitary form(FC)(14%). Predominant species were <italic>M. intracellulare</italic>(60%), <italic>M. avium</italic>(19%), <italic>M. abscessus subsp. abscessus</italic>(6%), and <italic>M. abscessus subsp. massiliense</italic>(4%). Over a median follow-up duration of 23.8 months, 42% received ≥ six months treatment. The favourable outcomes were higher in the NC-NB(80%) and C-NB(72%) vs. FC(30%). Factors such as male sex(p=0.025), lower body mass index(p=0.015), smear positivity(p=0.003), and serum Aspergillus antigen or antibody positivity (p<0.001) were associated with poorer outcomes. Among 56 patients with extensive or refractory, recurrent NTM-PD, 32% showed immune deficiency, including immunoglobulin(Ig) G subclass 3 (n=13), IgG subclass 4 (n=2), IgG subclass 3 and 4 (n=1), IgM(n=1), and IgG subclass G3 and IgM(n=1) deficiency. NTM-PD patients with FC phenotype exhibited worse treatment outcomes. Serum Aspergillus antigen/antibody positivity could serve as potential biomarkers for NTM-PD prognosis.