Brat Kristian, Plutinsky Marek, Hejduk Karel, Svoboda Michal, Popelkova Patrice, Zatloukal Jaromir, Volakova Eva, Fecaninova Miroslava, Heribanova Lucie, Koblizek Vladimir
Department of Respiratory Diseases, Faculty of Medicine, University Hospital Brno, Masaryk University, Brno, Czech Republic.
Faculty of Medicine, Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic.
Int J Chron Obstruct Pulmon Dis. 2018 Mar 26;13:1037-1052. doi: 10.2147/COPD.S147262. eCollection 2018.
Respiratory parameters are important predictors of prognosis in the COPD population. Global Initiative for Obstructive Lung Disease (GOLD) 2017 Update resulted in a vertical shift of patients across COPD categories, with category B being the most populous and clinically heterogeneous. The aim of our study was to investigate whether respiratory parameters might be associated with increased all-cause mortality within GOLD category B patients.
The data were extracted from the Czech Multicentre Research Database, a prospective, noninterventional multicenter study of COPD patients. Kaplan-Meier survival analyses were performed at different levels of respiratory parameters (partial pressure of oxygen in arterial blood [PaO], partial pressure of arterial carbon dioxide [PaCO] and greatest decrease of basal peripheral capillary oxygen saturation during 6-minute walking test [6-MWT]). Univariate analyses using the Cox proportional hazard model and multivariate analyses were used to identify risk factors for mortality in hypoxemic and hypercapnic individuals with COPD.
All-cause mortality in the cohort at 3 years of prospective follow-up reached 18.4%. Chronic hypoxemia (PaO <7.3 kPa), hypercapnia (PaCO >7.0 kPa) and oxygen desaturation during the 6-MWT were predictors of long-term mortality in COPD patients with forced expiratory volume in 1 second ≤60% for the overall cohort and for GOLD B category patients. Univariate analyses confirmed the association among decreased oxemia (<7.3 kPa), increased capnemia (>7.0 kPa), oxygen desaturation during 6-MWT and mortality in the studied groups of COPD subjects. Multivariate analysis identified PaO <7.3 kPa as a strong independent risk factor for mortality.
Survival analyses showed significantly increased all-cause mortality in hypoxemic and hypercapnic GOLD B subjects. More important, PaO <7.3 kPa was the strongest risk factor, especially in category B patients. In contrast, the majority of the tested respiratory parameters did not show a difference in mortality in the GOLD category D cohort.
呼吸参数是慢性阻塞性肺疾病（COPD）患者预后的重要预测指标。《慢性阻塞性肺疾病全球倡议》（GOLD）2017年更新版导致各COPD类别患者出现垂直转移，其中B类患者数量最多且临床异质性最强。我们研究的目的是调查呼吸参数是否可能与GOLD B类患者全因死亡率增加相关。
数据取自捷克多中心研究数据库，这是一项针对COPD患者的前瞻性、非干预性多中心研究。在不同呼吸参数水平（动脉血氧分压[PaO]、动脉血二氧化碳分压[PaCO]以及6分钟步行试验[6-MWT]期间基础外周毛细血管血氧饱和度的最大降幅）进行了Kaplan-Meier生存分析。使用Cox比例风险模型进行单因素分析，并进行多因素分析以确定COPD低氧血症和高碳酸血症患者的死亡风险因素。
前瞻性随访3年时，队列中的全因死亡率达到18.4%。慢性低氧血症（PaO<7.3 kPa）、高碳酸血症（PaCO>7.0 kPa）以及6-MWT期间的氧饱和度下降是1秒用力呼气量≤60%的COPD患者总体队列和GOLD B类患者长期死亡的预测指标。单因素分析证实了低氧血症（<7.3 kPa）降低、高碳酸血症（>7.0 kPa）增加、6-MWT期间氧饱和度下降与所研究的COPD受试者组死亡率之间的关联。多因素分析确定PaO<7.3 kPa是死亡的强有力独立风险因素。
生存分析显示，GOLD B类低氧血症和高碳酸血症患者的全因死亡率显著增加。更重要的是，PaO<7.3 kPa是最强的风险因素，尤其是在B类患者中。相比之下，大多数测试的呼吸参数在GOLD D类队列的死亡率中未显示出差异。
