The role of pulmonary arterial pressure in chronic obstructive pulmonary disease phenotypes based on cluster analysis and its prognostic value

Abstract

Objective: To explore the role of pulmonary arterial pressure in chronic obstructive pulmonary disease (COPD) phenotypes based on cluster analysis and its prognostic value. Methods: Three hundred and nineteen patients admitted to Beijing Chaoyang Hospital and Xuanwu Hospital from April 2013 to April 2016 were recruited in the study. All the patients were older than 40 years old and in stable COPD. One-year follow-up was performed and the endpoint was acute exacerbation of COPD or all-cause mortality. Age, body mass index (BMI), smoking index, history of exacerbation, modified British medical research council (mMRC), forced expiratory volume in first second (FEV(1)), pulmonary arterial pressure and right ventricular transverse diameter measured by echocardiography were selected as cluster indicators to classify patients, survival analysis was performed. Results: Eight cluster indexes were converted into four independent principal components by principal component analysis (PCA), with a cumulative contribution rate of 70.1%. The extracted principal components were used for cluster analysis. Patients were divided into four categories, each contained different GOLD grades and had statistically significant differences in age, symptoms, degree of pulmonary function impairment and pulmonary arterial pressure (all P<0.001). The four categories were: class 1: young, pulmonary function damage was medium, lower pulmonary arterial pressure, good prognosis; class 2: elderly, pulmonary function damage was mild, higher pulmonary arterial pressure, poor prognosis; class 3: young, pulmonary function damage was serious, normal pulmonary arterial pressure, the best prognosis; class 4: elderly, pulmonary function damage was medium, pulmonary arterial pressure increased significantly, the worst prognosis. Conclusion: Cluster analysis based on pulmonary artery pressure can be used to identify COPD patients with different risk of acute exacerbation or death, suggesting that pulmonary hypertension as a COPD phenotype plays a role in prognostic assessment.