Cho K, et al. Tuberc Respir Dis. 2012 May;72(5):416-425. http://dx.doi.org/10.4046/trd.2012.72.5.416

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease with variable clinical manifestations, structural changes, and treatment responses. In a cohort study, we performed a baseline cluster analysis to identify the subgroups of COPD and to assess the clinical outcomes of each subgroup during a 1-year follow-up. We analyzed dusty areas cohort comprising 272 patients with COPD. The main factors with the highest loading in 15 variables were selected using principal component analysis (PCA) at baseline. The COPD patients were classified by hierarchical cluster analysis using clinical, physiological, and imaging data based on PCA-transformed data. The clinical parameters and outcomes during the 1-year follow-up were evaluated among the subgroups. PCA revealed that six independent components accounted for 77.3% of variance. Three distinct subgroups were identified through the cluster analysis. Subgroup 1 included younger subjects with fewer symptoms and mild airflow obstruction, and they had fewer exacerbations during the 1-year follow-up. Subgroup 2 comprised subjects with additional symptoms and moderate airflow obstruction, and they most frequently experienced exacerbations requiring hospitalization during the 1-year follow-up. Subgroup 3 included subjects with additional symptoms and mild airflow obstruction; this group had more female patients and a modest frequency of exacerbations requiring hospitalization. Cluster analysis using the baseline data of a COPD cohort identified three distinct subgroups with different clinical parameters and outcomes. These findings suggest that the identified subgroups represent clinically meaningful subtypes of COPD.

Patients with chronic thromboembolic pulmonary hypertension (CTEPH) require lifelong anticoagulant therapy. The safety and efficacy of direct oral anticoagulant (DOAC) in the chronic and transitional management of CTEPH has not been investigated. We performed a retrospective analysis of 405 consecutive pulmonary endarterectomy (PEA) cases at the University of California, San Diego, from July 2015 through July 2017. PEA specimen was reviewed for the presence of acute or subacute thrombotic material distinct from the expected chronic disease removed at the time of PEA by two investigators blinded to the patient information. Of 405 PEA cases, 166 patients (41.0%) were anticoagulated with one of three available DOACs; 239 (59.0%) presented on either oral vitamin‐K antagonist or chronic injectable therapy. There were no significant differences in baseline characteristics between DOAC and non‐DOAC groups. Evidence of recent thrombus was observed in 22 (13.3%) in the DOAC group versus 16 (6.7%) within the non‐DOAC group. The odds ratio of DOACs usage and evidence of recent thrombus was 2.34 (95% confidence interval: 1.1–5.0, p = 0.03) after adjusting for age, gender, race, body mass index, and history of antiphospholipid antibody syndrome. CTEPH patients referred for PEA while on DOAC therapy were twice as likely to have associated acute or subacute thrombi present at the time of surgery compared with those on more traditional, non‐DOAC anticoagulant therapies. This raises questions of the safety and efficacy of DOACs in the chronic management of CTEPH.

Lee C, et al. Infect Chemother. 2020 Sep;52(3):369-380. https://doi.org/10.3947/ic.2020.52.3.369

Lee S, et al. Tuberc Respir Dis. 2014 Oct;77(4):178-183. http://dx.doi.org/10.4046/trd.2014.77.4.178

Lim G, et al. Tuberc Respir Dis. 2014 Jun;76(6):276-283. http://dx.doi.org/10.4046/trd.2014.76.6.276