Purpose: As the number of patients with Mycobacterium avium complex lung disease is significantly increasing worldwide, several studies have focused on the prognostic factors associated with the disease. This systematic review investigated the factors associated with mortality among patients with Mycobacterium avium complex lung disease. Methods: Two investigators independently identified studies that were designed to determine risk factors for mortality in patients with Mycobacterium avium complex lung disease from PubMed, the Cochrane Register of Control Trial database, and EMBASE (accessed on 25 November 2022). Results: Of the 1133 titles and abstracts screened, 54 full texts were selected for review, and 15 studies were finally included in this systematic review. The most commonly studied risk factors were advanced age and low body mass index (11 studies for each), followed by male sex (8 studies), hypoalbuminemia (5 studies), and cavity (5 studies). In each study, these factors were mostly associated with increased all-cause mortality among patients with Mycobacterium avium complex lung disease as confirmed via multivariate analysis. Conclusions: Advanced age, male sex, low body mass index, hypoalbuminemia, and cavity are likely to be the common risk factors for all-cause mortality among patients with Mycobacterium avium complex lung disease, suggesting that patients with these factors need to be carefully monitored.

The pathogenesis of pleuroparenchymal fibroelastosis (PPFE), a rare interstitial lung disease, remains unclear. Based on previous reports and our experience, we hypothesized that alveolar epithelial denudation (AED) was involved in the pathogenesis of PPFE. This multicenter retrospective study investigated the percentage of AED and the features of the denudated areas in 26 PPFE cases, 30 idiopathic pulmonary fibrosis (IPF) cases, and 29 controls. PPFE patients had lower forced vital capacities and higher residual volume/total lung capacities in pulmonary function tests compared to IPF and control patients. Histopathologically, subpleural fibroelastosis was observed in PPFE, and AED was observed in 12.01% of cases in the subpleural or interlobular septa regardless of fibroelastosis. The percentage of AED in the PPFE group was significantly higher than that in the IPF group (6.84%; p = 0.03) and the normal group (1.19%; p < 0.001). In the IPF group, the percentage of AED and the presence of PPFE-like lesions in the upper lobes were examined radiologically, but no correlation was found. We showed that AED frequently occurred in PPFE. AED was less frequent in IPF, which, in combination with imaging data, suggests that PPFE may have a different pathogenesis from IPF.

Objective: Skeletal muscle size is considered a predictor of prognosis in patients with respiratory diseases including Mycobacterium avium complex lung disease. However, no research focused on its impact on prognosis in patients with pulmonary tuberculosis (TB). Thus, this study aimed to assess the association between erector spinae muscle (ESM) size and in-hospital mortality among patients with pulmonary TB. Results: We retrospectively included 258 consecutive patients aged over 65 years old, who were admitted to the hospital for bacteriologically confirmed pulmonary TB, and all underwent chest computed tomography (CT) scan upon admission. The cross-sectional area of the ESM (ESMcsa) was measured at the lower margin of the 12th thoracic vertebra on a single-slice CT scan image and was adjusted according to body surface area (BSA). In total, 71 (28%) patients died during hospitalization. The non-survivor group had a high incidence of respiratory failure and comorbidities and lower hemoglobin and albumin levels, performance status score, and ESMcsa/BSA. Multivariate analysis revealed that low performance status score and hemoglobin and albumin levels, but not ESMcsa/BSA and body mass index, could independently predict in-hospital mortality after adjusting for age and comorbidities. Therefore, ESM size was not associated with in-hospital mortality in patients with pulmonary TB.

Pleuroparenchymal fibroelastosis (PPFE) is a newly described entity of interstitial lung disease, which has been recently recognized as a rare complication of bone marrow transplantation. We report a case of 30-year-old man who developed a unique combination of pleuroparenchymal fibroelastosis with cellular and fibrotic non-specific interstitial pneumonia (NSIP) and bronchiolitis obliterans (BO) sixteen years after hematopoietic stem cell transplantation. Histological examination revealed almost exclusive infiltration of CD3-positive T lymphocytes associated with lymphoepithelial lesions and multi-focal denudation of covering epithelial cells in all components. This case suggests PPFE, NSIP, and BO might be conditions of the same spectrum, pathogenetically related to chronic graft-versus-host disease. Immunostaining for CD3 and CD20 in transbronchial lung biopsies may be helpful for identifying graft-versus-host-driven interstitial lung disease.

Non-conversion of sputum culture or smear within 2 months after the start of treatment is a known poor prognostic factor of pulmonary tuberculosis. In elderly patients, sputum conversion may be delayed because of the age-related decline in immune competence. This study aimed to assess how a long interval to sputum conversion predicts in-hospital mortality in elderly patients with pulmonary tuberculosis. Consecutive elderly patients (age > 65 years) who were admitted to our institution for bacteriologically confirmed pulmonary tuberculosis were included. The association between sputum conversion within 30, 60, 90, or 120 days from the start of treatment and in-hospital mortality were analyzed by Cox proportional-hazards regression after adjustment for other potential variables. This study included 262 patients, and 74 patients (28%) died during hospitalization. Multivariate analyses showed that sputum non-conversion within 90 days (adjusted hazard ratio 0.424, 95% CI 0.252–0.712, p = 0.001) or 120 days (0.333, 0.195–0.570, p < 0.001) was independently associated with in-hospital mortality, whereas that within 60 days was not (p = 0.890). In elderly patients with tuberculosis, 2 months may be insufficient when evaluating sputum conversion as a prognostic factor. Sputum non-conversion within 90 days or longer may predict in-hospital mortality more accurately.

Although Klebsiella pneumoniae pneumonia is an insidious threat among the elderly, the role of radiological features has not been elucidated. We aimed to evaluate thin-section chest computed tomography (CT) features and assess its associations with disease prognosis in elderly patients with acute K. pneumoniae pneumonia. We retrospectively included elderly patients, admitted for acute K. pneumoniae pneumonia, and investigated thin-section CT findings to determine whether bronchopneumonia or lobar pneumonia was present. The association between the radiological pattern of pneumonia and in-hospital mortality was analyzed. Eighty-six patients with acute K. pneumoniae pneumonia were included, and among them, the bronchopneumonia pattern was observed in 70 (81%) patients. Twenty-five (29%) patients died in hospital, and they had a greater incidence of lobar pneumonia pattern (40% in nonsurvivors vs 10% in survivors; P = .008), low albumin level (2.7 g/dL, range, 1.6–3.8 in nonsurvivors vs 3.0 g/dL, range, 1.7–4.2 in survivors; P = .026) and higher levels of aspartate aminotransferase (30 U/L, range, 11–186 in nonsurvivors vs 23 U/L, range, 11–102 in survivors, P = .017) and C-reactive protein (8.0 mg/dL, range, 0.9–26.5 in nonsurvivors vs 4.7 mg/dL, range, 0.0–24.0 in survivors; P = .047) on admission. Multivariate analysis showed that lobar pneumonia pattern was independently associated with increased in-hospital mortality (adjusted hazard ratio, 3.906; 95% CI, 1.513–10.079; P = .005). In elderly patients with acute K. pneumoniae pneumonia, the lobar pneumonia pattern may be less commonly observed, and this pattern could relate to poor prognosis.