In South Korea, the National Tuberculosis Expert Review Committee (NTBERC) has authorized the use of bedaquiline and delamanid in patients with multidrug-resistant or rifampin-resistant tuberculosis (MDR/RR-TB) since September 1, 2016. We aimed to evaluate the treatment outcomes in patients who used these drugs under NTBERC approval prior to the introduction of short-course all-oral regimens. This nationwide cohort study included patients with pulmonary MDR/RR-TB whose NTBERC-approved treatment included bedaquiline and/or delamanid and was initiated between September 1, 2016, and December 31, 2022. Treatment outcomes were categorized according to 2013 WHO definitions, and the treatment success rate was defined as the proportion of patients in the “cured” and “treatment completed” categories. During the study period, 2,078 patients applied for NTBERC approval, and 1,985 (95.5

Vitamin D modulates antimycobacterial immunity, and its deficiency has been implicated in susceptibility to nontuberculous mycobacterial pulmonary disease (NTM-PD). However, whether baseline vitamin D status influences treatment outcomes remains unclear. We analyzed 485 patients with available baseline serum 25-hydroxyvitamin D [25(OH)D] levels and 6-month culture data from a prospective multicenter cohort (NTM-KOREA) enrolled between April 2022 and August 2025. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. The mean age was 64.0 years, 73.2% were female, and 99 (20.4%) had vitamin D deficiency. The overall 6-month culture conversion rate was 44.9%, with no significant difference between deficient and non-deficient groups (42.4% vs. 45.6%; p = 0.651). In multivariable logistic regression, vitamin D deficiency was not associated with culture conversion (adjusted odds ratio [aOR] 1.091; 95% CI 0.662-1.797; p = 0.733), whereas guideline-based treatment showed a strong positive association (aOR 3.781; 95% CI 1.825-7.832; p < 0.001). Multivariable Cox regression confirmed no association between vitamin D deficiency and time to conversion (adjusted hazard ratio 1.031; 95% CI 0.721-1.475; p = 0.868). Baseline vitamin D deficiency was not independently associated with 6-month culture conversion or time to conversion in treated NTM-PD patients.

Tuberculosis and non-tuberculous mycobacterial pulmonary disease (NTM-PD) are major causes of chronic respiratory morbidity, yet detailed multicenter clinical data remain limited. We established a retrospective multicenter cohort using electronic medical records from 4 national university-affiliated tertiary hospitals in Korea. Eligible participants included patients with tuberculosis registered in the Korean National Tuberculosis Surveillance System and patients who met modified 2007 American Thoracic Society/Infectious Diseases Society of America microbiological criteria for NTM-PD between 2015 and 2024. De-identified, standardized datasets were created using common data specifications and harmonized at a central coordinating center. The cohort included 11,790 patients with tuberculosis and 5,145 patients with NTM-PD. Tuberculosis notifications declined steadily from 1,657 cases in 2015 to 580 cases in 2024, whereas NTM-PD showed an overall upward trend despite a modest decrease in the final year. Mycobacterium avium complex accounted for 78.7% of NTM-PD cases, with M. intracellulare and M. avium as the predominant species. Macrolide-based multidrug regimens were used consistently throughout the study period. This cohort profile describes the registry design, case definitions, data structure, and key baseline findings; the registry provides a platform for future clinical, epidemiological, and health-services research on mycobacterial disease in Korea.

Background Cavity on chest radiograph is recognized as an independent risk factor for recurrence in pulmonary tuberculosis (TB), but evidence supporting extended treatment in these patients remains limited, particularly in real-world data from Korea. Methods We performed a retrospective analysis using data from a multicenter prospective cohort of patients with pulmonary tuberculosis enrolled at 18 Korean institutions, comparing recurrence rates between standard treatment (≤200 days) and extended treatment (>200 days) among drug-susceptible pulmonary TB patients with cavity on chest radiograph. Results Among 159 patients, 58 (36.5%) received standard treatment and 101 (63.5%) received extended treatment. Baseline sputum smear positivity was higher in the extended group (29.3% vs. 56.4%, p = 0.002), but 2-month culture positivity (6.3% vs. 4.4%, p > 0.999) and time to culture conversion (8.00 ± 3.91 vs. 7.45 ± 3.73 weeks, p = 0.454) were similar. Recurrence during post-treatment follow-up occurred in 4 patients (2.5%) and did not differ between groups (3.4% vs. 2.0%, p = 0.966). Treatment interruption due to adverse drug reactions was more frequent with extended treatment (1.7% vs. 7.9%, p = 0.204), while overall adverse event rates were comparable. In a fixed-time analysis using Firth’s penalized logistic regression, extended treatment showed a numerically lower risk of recurrence, although statistical significance was not reached (adjusted odds ratio [aOR], 0.07; 95% confidence interval [CI], 0.01–1.06; p = 0.056). Among covariates, low body mass index was associated with recurrence, but this estimate was very imprecise and should be interpreted with caution. Conclusion Cavity on chest radiograph alone may not be sufficient to justify routine extension of treatment beyond 200 days. Because only four recurrence events were observed, the adjusted association favoring extended treatment was imprecise and should be interpreted as exploratory rather than definitive. Larger prospective studies that systematically capture microbiologic response and detailed radiologic disease burden are needed to identify which patients with cavitary disease may benefit from individualized treatment extension.

Mycobacterium avium complex pulmonary disease (MAC-PD) frequently recurs after treatment but predictors of recurrence remain unclear. We retrospectively analysed patients with successfully treated MAC-PD from two tertiary centres. Chest CT findings-including bronchiectasis, cellular bronchiolitis, cavity, nodule and consolidation scores-were assessed before and after treatment. Multivariable competing risk regression analyses were performed to identify factors associated with recurrence. Among 538 patients, 216 (40.1%) experienced recurrence. A higher post-treatment cellular bronchiolitis score was independently associated with recurrence (adjusted subdistribution HR 1.64, 95% CI 1.46 to 1.84; p<0.001). A score ≥3 was associated with increased recurrence risk in both nodular bronchiectatic and fibrocavitary phenotypes. Residual cellular bronchiolitis on post-treatment CT demonstrated the strongest predictive performance and may serve as a radiological marker of recurrence risk.

Evidence on the association between nutritional status and clinical characteristics in nontuberculous mycobacterial pulmonary disease (NTM-PD) remains limited. We investigated this association and its impact on longitudinal outcomes in a nationwide cohort. We analysed 627 patients from the NTM-KOREA cohort study who had initiated antibiotic therapy for NTM-PD. Baseline nutritional status was assessed using the Prognostic Nutritional Index (PNI) and Mini Nutritional Assessment Short Form (MNA-SF) tools. Clinical characteristics, physical function, and health-related quality of life (HRQOL) using Quality of Life Questionnaire–Bronchiectasis (QOL-B) were evaluated. Longitudinal analyses were performed at 6 and 12 months after therapy initiation. In the baseline anlysis group (N = 627; mean age: 64.3 ± 9.7 years; females: 73.7

The standard treatment for drug-susceptible tuberculosis (TB) is a 6-month short-course regimen; however, extended courses are often used in clinical practice. We aimed to identify factors associated with extended treatment in patients with drug-susceptible TB. We conducted a prospective cohort study across 18 institutions in the Republic of Korea between July 2019 and June 2023 and enrolled patients with drug-susceptible TB who received the standard short-course regimen (isoniazid, rifampin, pyrazinamide, and ethambutol) and achieved treatment success at end of therapy. Patients were categorised by treatment duration: less than 200 days (standard treatment group) and more than 200 days (extended treatment group). Of 854 patients, 334 (39.1

BACKGROUND:Small cell lung cancer (SCLC) is called 'smoker's disease' because it is strongly associated with smoking and most cases occur in smokers. However, it can also occur in never smokers. We investigated the clinical features of never smokers with SCLC and compared their treatment outcomes with those of smokers with SCLC. METHODS:We retrospectively reviewed the clinical data of patients who had proven SCLC and had received chemotherapy at a single cancer center between July 2002 and April 2021. RESULTS:Of 1,643 patients, 1,416 (86.2%) were enrolled in this study. A total of 162 (11.4%) and 1,254 (88.6%) patients were never smokers and smokers, respectively. There were more female never smokers than smokers (n=130; 80.2% vs. 79, 6.3%, p=0.000), and the incidence of ischemic heart disease was lower among never smokers than among smokers (4/1,416, [2.5%] vs. 83/1,416 [6.6%], p=0.036). Never smokers showed less symptoms at diagnosis than smokers (80.9% vs. 87.2%, p=0.037); however, they showed more toxicity after first-line treatment (61.7% vs. 47.8%, p=0.001). The objective response rate (ORR) was significantly higher in never smokers (74.1% vs. 59.6%, p=0.000). In the multivariate analysis, never smoking and second-line treatment were associated with a better ORR. However, progression-free survival and overall survival were not significantly different between never smokers and smokers. CONCLUSION:In conclusion, never smokers accounted for 11.4% of patients with SCLC. They had distinguishing clinical characteristics and showed better chemotherapeutic responses than smokers.

The evaluation of health-related quality of life (HRQOL) is gaining importance among patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). We assessed whether the BACES score reflects HRQOL and associated factors in these patients. Data were collected from the nationwide NTM-KOREA prospective cohort of patients with NTM-PD who started antibiotic treatment and included symptoms, Quality of Life-Bronchiectasis (QOL-B) questionnaire, nutritional status using the Mini Nutritional Assessment-Short Form (MNA-SF) and Prognostic Nutritional Index (PNI), physical activity, body composition, spirometry, handgrip strength, and 6-min walking distance. Multivariate linear and logistic regressions were used for analysis. As the BACES score increased, so did the odds (adjusted odds ratio [95% confidence interval]) of cough (1.24 [1.04-1.48]), dyspnea (1.69 [1.28-2.27]), weight loss (1.78 [1.36-2.36]), and malnutrition, defined as MNA-SF score ≤ 7 (1.71 [1.21-2.45]), and PNI < 45 (2.14 [1.66-2.81]). The QOL-B respiratory symptom score (estimate: -2.259, P = 0.002) and 6-min walking distance (estimate: -18.015, P < 0.001) were negatively associated with the BACES score. Moreover, the odds of adipopenia (1.08 [1.03-1.13]), possible sarcopenia (1.80 [1.35-2.45]), and sarcopenia (2.09 [1.48-3.03]) increased in women. The BACES score can estimate HRQOL and associated conditions at antimicrobial treatment initiation in patients with NTM-PD.

Background Growing concern has emerged regarding the disease burden and longterm outcomes associated with post-tuberculosis lung disease (PTLD). This study is designed to assess the long-term effects of tuberculosis (TB) on lung health and quality of life, aiming to fill the critical evidence gap in PTLD research. Methods This investigation utilizes a nationwide, prospective, multicenter observational cohort design. Seven tertiary healthcare centers in Korea will recruit at least 350 participants in the treatment-phase group (with a minimum of 50 participants per site) between June 2025 and December 2026. Eligible participants are individuals aged ≥19 years who are either in the course of anti-TB treatment (treatment-phase group), or have previously completed treatment for pulmonary TB (post-treatment group). Exclusion criteria are diagnosis limited to extrapulmonary TB, age <19 years, or refusal to provide consent. Data will be gathered at baseline and annually for up to 5 years until December 2031. Baseline assessments will capture demographic characteristics, TB-related clinical history, relevant comorbidities, and medication use. Initial laboratory evaluations will cover blood analysis, urinalysis, and electrocardiographic measurements. Comprehensive clinical evaluations include symptom scoring, spirometry, chest imaging, and administration of quality of life questionnaires. Annual follow-up will involve repeating spirometry, chest imaging, and quality of life assessments. No additional interventions beyond routine clinical care will be mandated by the study protocol. All collected data will be anonymized and managed securely, adhering to both institutional and ethical regulatory standards (ClinicalTrials.gov: NCT06946784). Conclusion This will be the first nationwide observational cohort investigating PTLD in Korea, delivering key real-world evidence to inform national and international post-TB management policies.

BACKGROUND:Bacterial co-infection has been associated with adverse outcomes in patients with COVID-19. Streptococcus pneumoniae is a common cause of community-acquired pneumonia and may contribute to poor clinical outcomes when co-detected in COVID-19 patients. This study aimed to investigate the clinical significance of pneumococcal positivity in hospitalized patients with COVID-19. METHODS:We conducted a retrospective analysis of adult patients hospitalized with COVID-19 at two tertiary care centers. Pneumococcal positivity was defined by either a positive urinary antigen test or multiplex real-time polymerase chain reaction. Disease severity of COVID-19 pneumonia was assessed using the pneumonia severity index and CURB-65 scoring systems. Propensity score matching and multivariable logistic regression were used to adjust for confounders and identify independent risk factors for mortality. RESULTS:Among 280 patients, 65 pneumococcus-positive patients were matched with 65 pneumococcus-negative patients after propensity score matching. In the overall matched cohort, pneumococcal positivity was not significantly associated with in-hospital mortality. However, in patients with severe disease (n = 156), defined as pneumonia severity index >130 or CURB-65 ≥ 3, mortality was significantly higher in pneumococcus-positive patients (n = 39) than in pneumococcus-negative patients (53.8% vs. 29.1%, p = 0.009). In the multivariable analysis of this subgroup, pneumococcal positivity (odds ratio, 4.050; 95% confidence interval, 1.285-12.765; p = 0.017) and high-flow oxygen therapy (odds ratio, 6.510; 95% confidence interval, 1.847-22.944; p = 0.004) were independently associated with mortality. CONCLUSION:Detection of S. pneumoniae by urinary antigen test or multiplex polymerase chain reaction was associated with increased mortality in patients hospitalized with severe COVID-19.

Background: This study aimed to determine whether a shorter high-dose rifampicin regimen is non-inferior to the standard 6-month tuberculosis regimen. Methods: This multicenter, randomized, open-label, non-inferiority trial enrolled participants with respiratory specimen positivity by Xpert MTB/RIF assay or Mycobacterium tuberculosis culture without rifampicin-resistance. Participants were randomized at 1:1 to the investigational or control group. The investigational group received high-dose rifampicin (30 mg/kg/day), isoniazid, and pyrazinamide until culture conversion, followed by high-dose rifampicin and isoniazid for 12 weeks. The control group received the standard 6-month regimen. The primary outcome was the rate of unfavorable outcomes at 18 months post-randomization. The non-inferiority margin was set at <6% difference in unfavorable outcomes rates. The study is registered with ClinicalTrials.gov (NCT04485156) Results: Between 4 November 2020 and 3 January 2022, 76 participants were enrolled. Of these, 58 were included in the modified intention-to-treat analysis. Unfavorable outcomes occurred in 10 (31.3%) of 32 in the control group and 10 (38.5%) of 26 in the investigational group. The difference was 7.2% (95% confidence interval, infinity to 31.9%), failing to prove non-inferiority. Serious adverse events and grade 3 or higher adverse events did not differ between the groups. Conclusion: The shorter high-dose rifampicin regimen failed to demonstrate non-inferiority but had an acceptable safety profile.

Background Although OM-85 may lessen respiratory symptoms and reduce acute exacerbations in chronic obstructive pulmonary disease (COPD), proof of its overall effectiveness remains incomplete. Methods This prospective, observational, single-arm study was conducted at four university hospitals in South Korea from June 2022 to December 2023. Adults with spirometry-confirmed COPD who were prescribed OM-85 were enrolled, and followed for 6 months (3-months treatment, 3-months observation). Symptoms and health-related quality of life were assessed using the modified Medical Research Council scale, COPD Assessment Test (CAT), and St. George’s Respiratory Questionnaire (SGRQ). Acute exacerbations and adverse events were recorded. Results Of the 323 patients analyzed (mean age 73.3±7.8 years; 83.9% male), 39.0% had baseline CAT ≥10. Patients in this group experienced markedly greater and sustained improvements in both CAT and SGRQ scores compared with those with CAT <10 (p for interaction <0.001 for both), and the magnitude of these changes exceeded the minimal clinically important difference (CAT: −3.21±3.85; SGRQ: −10.42±14.87 at 6 months), indicating clinically meaningful symptom relief. Among these patients, achieving SGRQ responder status at 6 months was negatively associated with an increased frequency of acute exacerbations (odds ratio, 0.246; 95% confidence interval, 0.050 to 1.207; p=0.084), showing a nonsignificant trend. OM-85 was well tolerated, with only mild, reversible drugrelated adverse events. Conclusion OM-85 treatment resulted in meaningful improvements in symptoms and healthrelated quality of life, particularly among patients with more severe baseline symptoms, and was in general well tolerated.

BACKGROUND:Depression is common in the elderly and has been linked with poor tuberculosis treatment outcomes. METHODS:We conducted a prospective multicenter cohort study of adult aged ≥ 65 years with active tuberculosis in the Republic of Korea between 2020 and 2022. Sociodemographic and clinical data were obtained by interview. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with a score ≥10 indicating a depressive episode. Logistic regression analyses were conducted to identify factors associated with depressive episodes and evaluate their association with treatment outcomes. RESULTS:Among the 361 elderly individuals with active tuberculosis who completed the questionnaire, 69 (19.1%) were classified as having a depressive episode. Depressive episodes were significantly associated with unemployment, higher comorbidity burden, and the presence of tuberculosis-related symptoms such as cough and constitutional symptoms. Functional impairment was reported in 39.6% (143/361) of all participants and increased with the greater severity of depressive symptoms. Suicidal ideation was observed in 19.7% (71/361) of all participants and was independently associated with alarming tuberculosis symptoms. Among the participants with rifampin-susceptible tuberculosis, those with depressive episodes had significantly lower treatment success rates (64.7% vs. 79.1%, p = 0.012). In multivariable logistic regression analysis, depression remained independently associated with reduced odds of treatment outcomes (adjusted odds ratio, 0.478; 95% confidence interval, 0.261-0.878). CONCLUSIONS:In elderly individuals with tuberculosis, depressive episodes are associated with functional impairment, suicidal ideation, and poor treatment outcomes. Routine mental health assessments at tuberculosis diagnosis may help improve clinical outcomes in aging populations.

Roflumilast, a phosphodiesterase 4 (PDE4) inhibitor, reduces neutrophilic airway inflammation and exacerbations in chronic obstructive pulmonary disease (COPD). However, the effect of coexisting bronchiectasis on its efficacy remains unclear. This study evaluates the long-term impact of roflumilast use in this population. A retrospective cohort study was conducted using data from 2,181 COPD patients. Of them, 180 had bronchiectasis confirmed on CT, with 162 not using roflumilast and 18 receiving it. Baseline data, including demographics, symptom scores, pulmonary function, and biomarkers, were collected. Patients were followed for one year to assess exacerbations and mortality, and survivors were monitored for up to three years for symptom and pulmonary function changes. Multivariate logistic regression was performed to determine predictors of exacerbations. Moderate and severe exacerbations occurred more frequently in the roflumilast group, but mortality did not differ between groups. Roflumilast users showed significant improvements in post-bronchodilator forced expiratory volume in one second (FEV1) (p=0.028), as well as in the ratio of forced expiratory volume in one second to the forced vital capacity (FEV1/FVC) ratio (p=0.015) compared to no roflumilast group. In multivariate analysis, roflumilast use was independently associated with a higher exacerbation risk (p=0.004, OR=14.643, 95% CI: 2.36-90.848). While roflumilast improved pulmonary function and symptoms in COPD patients with bronchiectasis, it was also linked to a higher risk of exacerbations. These findings suggest caution in its use for this population, and further randomized controlled trials are needed to assess its safety and efficacy.

INTRODUCTION:Guideline-discordant low-dose computed tomography (LDCT) screening may cause lung cancer (LC) overdiagnosis, but its extent and consequences are unclear. This study aimed to investigate the prevalence of self-initiated, non-reimbursed LDCT screening in a predominantly non-smoking population and its impact on LC epidemiology and healthcare utilization. METHODS:This nationwide cohort study analyzed data from Korea's National Health Information Database and 11 academic hospital screening centers (1999-2022). The overall analysis encompassed the entire Korean population. For non-reimbursed LDCT screening prevalence, which the National Health Information Database does not capture, a separate analysis was conducted on a cohort of 1.7 million adults to extrapolate nationwide rates. Outcomes included trends in self-initiated, non-reimbursed LDCT screening, LC incidence, mortality, stage and age at diagnosis, 5-year survival, and LC-related healthcare utilization, including surgeries and biopsies. Joinpoint regression assessed trend changes. RESULTS:Self-initiated, non-reimbursed LDCT screening during health check-ups increased from 29% to 60% in men and 7% to 46% in women, despite only 2.4% of men and 0.04% of women qualifying for risk-based screening. In women, localized-stage LC incidence nearly doubled (age-standardized incidence rate: from 7.6 to 13.7 per 100,000), whereas distant-stage incidence decreased (age-standardized incidence rate: from 16.1 to 15.0 per 100,000). LC mortality declined (age-standardized mortality rate: from 23.3 to 19.8 per 100,000), whereas 5-year survival rates improved substantially. LC diagnoses in women shifted towards earlier stages and younger ages. Lung surgeries for both malignant and benign lesions, frequently lacking nonsurgical biopsies, increased sharply in women. CONCLUSIONS:Widespread guideline-discordant LDCT screening correlates with LC overdiagnosis and increased healthcare utilization, particularly in women. Randomized controlled trials are needed to assess the risks and benefits of screening in low-risk populations to determine its efficacy and consequences.

Background Improving health-related quality of life (HRQOL) has emerged as a priority in the management of nontuberculous mycobacterial pulmonary disease (NTM-PD). We aimed to evaluate HRQOL and its changes after 6 months' treatment in patients with NTM-PD.Methods The NTM-KOREA is a nationwide prospective cohort enrolling patients initiating treatment for NTM-PD in 8 institutions across South Korea. We conducted the Quality of Life-Bronchiectasis (QOL-B) at 6-month intervals and evaluated baseline scores (higher scores indicate better quality of life) and changes after 6 months' treatment. Multivariate logistic regression was performed to identify factors associated with improvement in the QOL-B physical functioning and respiratory symptoms domains.Results Between February 2022 and August 2023, 411 patients were included in the analysis. Baseline scores (95% confidence interval [CI]) for physical functioning and respiratory symptoms were 66.7 (46.7-86.7) and 81.5 (70.4-92.6), respectively. Among 228 patients who completed the QOL-B after 6 months' treatment, improvements in physical functioning and respiratory symptoms were observed in 61 (26.8%) and 71 (31.1%) patients, respectively. A lower score (adjusted odds ratio; 95% CI) for physical functioning (0.93; 0.91-0.96) and respiratory symptoms (0.92; 0.89-0.95) at treatment initiation was associated with a greater likelihood of physical functioning and respiratory symptom improvement, respectively; achieving culture conversion was not associated with improvement in physical functioning (0.62; 0.28-1.39) or respiratory symptoms (1.30; 0.62-2.74).Conclusions After 6 months of antibiotic treatment for NTM-PD, HRQOL improved in almost one-third, especially in patients with severe initial symptoms, regardless of culture conversion.Clinical Trials Registration ClinicalTrials.gov identifier: NCT03934034. After 6 months of antibiotic treatment for nontuberculous mycobacterial pulmonary disease, health-related quality of life improved in almost one-third of patients, particularly in patients with severe initial symptoms, regardless of culture conversion.