S21: Young Investigator Award Oral Presentation

"Background and Aims: Although international nontuberculous mycobacterial pulmonary disease (NTM-PD) guidelines highlight symptom presence at diagnosis, the clinical characteristics of asymptomatic Mycobacterium avium complex pulmonary infection (MAC-PI) patients remain understudied. We clarified the clinical characteristics and course of asymptomatic MAC-PI patients. Methods: We retrospectively analyzed 200 consecutive patients with MAC-PIs and adequate available data who newly met the microbiological and radiological criteria for NTM-PD at Fukujuji Hospital from January 2018 to June 2020. We compared the clinical characteristics and course of asymptomatic patients with symptomatic patients and evaluated factors influencing treatment initiation through multivariate analysis. Results: 111 patients were symptomatic and 89 were asymptomatic at diagnosis. While the proportion was significantly lower than that in the symptomatic group (28.8%), 15.7% of asymptomatic group patients had cavitary lesions (P = 0.042). In the asymptomatic group, treatments were initiated in 38 (42.7%) patients, and cavitary lesions, a positive acid-fast bacilli smear, and younger age were independent risk factors for treatment initiation. Among 22 (57.9%) patients who experienced disease progression necessitating treatment during follow-up, 13 (34.2%) displayed radiological progression without any worsening of symptoms. Agents used for treatment were consistent across the groups, with no significant differences in culture conversion, microbiological recurrence rates, or spontaneous culture conversion rates. Conclusion: Routine health checkups and radiological examinations can detect clinically important MAC-PIs even in the absence of symptoms. Considering that the clinical course of asymptomatic MAC-PI patients is largely similar to that of symptomatic patients, timely and appropriate management and intervention are essential for all MAC-PI patients."

Association Between CT-based Mucus Plug Score and Bendopnea in Patients with Chronic Obstructive Pulmonary Disease Author:　Toshitaka Shomura1), Yosuke Wada1), Zhang Ziele1), Yuika Nakamura2), Yusuke Suzuki1), Norihiko Goto1), Yoshiaki Kitaguchi1), Atsuhito Usiki1), Masanori Yasuo2), Masayuki Hanaoka1) Institute: 1) The first department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan 2)Departments of Clinical Laboratory Sciences, Shinshu University School of Health Sciences, Matsumoto, Nagano, Japan. Background and Aims Bendopnea, defined as dyspnea while bending forward, has been primarily studied in heart failure, but its significance in chronic obstructive pulmonary disease (COPD) remains unclear. Airway mucus plugging, quantified by computed tomography (CT), has emerged as an important imaging marker linked to airflow limitation and symptom burden in COPD. We hypothesized that a higher CT-based mucus plug score is independently associated with the presence of bendopnea in COPD patients. Methods We conducted a retrospective cross-sectional study of 133 patients with COPD. Bendopnea was assessed clinically and was present in 27 patients (20.3%). Mucus plug score was quantified from chest CT images. Patient demographics, pulmonary function tests, low attenuation volume percentage (LAV%), hemodynamic parameters (BNP, TRPG, EF), and symptom scores were compared between groups. Multivariate logistic regression analyses were performed to evaluate the independent association of mucus plug score with bendopnea, adjusting for %FEV1 and LAV%. Results Bendopnea-positive group exhibited significantly higher mucus plug scores compared to the Bendopnea-negative group (median 2.0 [IQR 1.0–4.0] vs. 0.0 [0.0–1.0], p < 0.001). The Bendopnea-positive group also demonstrated more severe airflow limitation (%FEV1: 51.3% vs. 73.7%, p < 0.001), greater emphysema (LAV%: 12.2% vs. 3.6%, p = 0.008). In contrast, hemodynamic parameters showed no significant between-group differences. In multivariate logistic regression analyses, mucus plug score remained a significant independent predictor of bendopnea across all models: adjusted for %FEV1, adjusted for LAV%, adjusted for both %FEV1 and LAV%. Bendopnea prevalence increased with rising mucus plug scores (P for trend < 0.001). Conclusions CT-based mucus plug score is significantly and independently associated with bendopnea in COPD patients, irrespective of the degree of airflow limitation, emphysema. These findings suggest that bendopnea may be a clinical clue to mucus-predominant airway disease in COPD.

Background The prognostic value of body mass index (BMI) in chronic obstructive pulmonary disease (COPD) remains inconsistent. The clinical implications of phenotyping based on adiposity and muscularity have not been well established. Methods In this prospective multicenter cohort study, patients with spirometry-confirmed COPD (October 2021–December 2023) underwent bioelectrical impedance analysis. Low fat-free mass index (FFMI) was defined as <17.4 kg/m² (men) and <15.0 kg/m² (women); high fat mass index (FMI) as ≥5.9 kg/m² (men) and ≥7.0 kg/m² (women). Participants were classified into four phenotypes: lean-robust (low FMI, high FFMI), wasting (low FMI, low FFMI), sarcopenic obesity (high FMI, low FFMI), and obese-robust (high FMI, high FFMI). The primary outcome was severe acute exacerbation; the secondary outcome was three-year all-cause mortality. Cox proportional hazards models were applied. Results Among 648 participants (mean age 73.2 years; 88.6% male), 6.9% were underweight, 29.9% overweight and 4.9% obese by BMI. Compared with normal weight, underweight was associated with higher risk of severe exacerbation (HR 2.05, 95% CI: 1.27–3.32) and mortality (HR 2.94, 95% CI: 1.50–5.77), whereas overweight showed lower mortality risk (HR 0.24, 95% CI 0.09–0.61). Based on adiposity–muscularity phenotyping, 21.9% were lean-robust, 28.4% wasting, 20.1% sarcopenic obesity, and 29.6% obese-robust. Using lean-robust as reference, wasting and sarcopenic obesity were associated with increased risks of severe exacerbation (HR 1.96, 95% CI:1.26-3.06; HR 1.81, 95% CI:1.12-2.94) and mortality (HR 12.6, 95% CI: 3.01-53.2; HR 15.2, 95% CI: 3.57-64.61). The obese-robust demonstrated comparable risks of severe exacerbation and mortality to the lean-robust group. Conclusion BMI alone inadequately stratifies prognosis in COPD. Phenotyping based on adiposity and muscularity identifies high-risk subgroups more precisely. The apparent obesity paradox may reflect preserved muscularity rather than adiposity itself, underscoring the importance of body composition assessment in clinical practice.