A Research Of The Clinical Characteristics Of Pulmonary Hypertension In Population With Chronic Obstructive Pulmonary Disease

Background and objective: Chronic obstructive pulmonary disease(COPD)is now the third leading cause of death worldwide.Chronic systemic or localized inflammation continuously remodels airway and alveolar structures,leading to a vicious cycle consisting of hypoxia,oxidative overload,and structural damage to the lungs,causing multiple complications for patients.Pulmonary hypertension(PH)is a common complication in patients with COPD and is a clear marker of poor prognosis.Researchers and clinicians have recognized that COPD patients with PH typically have poorer respiratory function.This recognition comes from a large number of clinical studies with similar outcomes.However,there is no conclusive evidence as to what type of COPD patients are more likely to develo P PH.In 2008,Chaouat et al.first introduced the term "disproportionate COPD-PH" and defined it as high m PAP(>35-40 mm Hg)with mild to moderate airflow limitation.In 2013,Seeger et al.suggested changing this concept to the more intuitive "COPD with SPH(COPD-SPH)" and explicitly suggested defining the threshold for severe pulmonary hypertension as m PAP ≥35 mm Hg.Also,Seeger et al.defined patients with m PAP ≥25 mm Hg as "COPD with PH(COPD-PH)".The aim of this study was to summarize the epidemiological and respiratory function characteristics of this population in the available evidence through a systematic review,while later exploring the factors influencing concurrent PH in COPD through a case-control study.Method and material: In the systematic review and meta-analysis,we followed the PRISMA statement and MOOSE statement,searched Pub Med,Embase,and Cochrane Library databases,and conducted a meta-analysis in R using the meta package after rigorous literature screening,quality assessment,and data extraction.In case-control study,we conducted case data collection by following a pre-drafted data table,and then applied R for statistical analysis,which mainly included analysis of variance analysis,correlation analysis,and regression analysis.Result: Combining the available evidence,the results of the meta-analysis suggest that the prevalence of COPD-SPH and COPD-PH may be 7% and 44%,respectively.Moreover,in COPD,the presence of PH is accompanied by deterioration of respiratory function,whereas the prevalence of PH does not increase with the deterioration of COPD.Compared to COPD-PH,COPD-SPH may have slightly better respiratory function but lower Pa O2.The results of the case-control part of the study suggest that in COPD patients,age,BMI,and DLCO/VA may be independent influences on pulmonary arterial pressure;higher age,lower weight,and poorer diffusion may be independent risk factors for the development of pulmonary hypertension.Conclusion:Based on the high incidence and unique clinical features of COPDPH,we suggest that clinical practice should involve increased monitoring of patients with advanced age,wasting,and impaired diffusion function,as well as more studies to explore the unique pathophysiological mechanisms of COPD-PH.However,due to the existence of various limitations such as few relevant studies,some of the findings could not be effectively interpreted,and more future studies on the mechanisms of concomitant PH in COPD patients are warranted.