Respiratory parameters predict poor outcome in COPD patients, category GOLD 2017 B

Int J Chron Obstruct Pulmon Dis. 2018 Mar 26:13:1037-1052. doi: 10.2147/COPD.S147262. eCollection 2018.

Abstract

Background: 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.

Methods: 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 [PaO2], partial pressure of arterial carbon dioxide [PaCO2] 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.

Results: All-cause mortality in the cohort at 3 years of prospective follow-up reached 18.4%. Chronic hypoxemia (PaO2 <7.3 kPa), hypercapnia (PaCO2 >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 PaO2 <7.3 kPa as a strong independent risk factor for mortality.

Conclusion: Survival analyses showed significantly increased all-cause mortality in hypoxemic and hypercapnic GOLD B subjects. More important, PaO2 <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.

Keywords: COPD; GOLD 2017 update; hypercapnia; hypoxemia; mortality.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Blood Gas Analysis
  • Comorbidity
  • Czech Republic
  • Databases, Factual
  • Female
  • Forced Expiratory Volume
  • Humans
  • Hypercapnia / diagnosis
  • Hypercapnia / mortality
  • Hypercapnia / physiopathology*
  • Hypercapnia / therapy
  • Hypoxia / diagnosis
  • Hypoxia / mortality
  • Hypoxia / physiopathology*
  • Hypoxia / therapy
  • Kaplan-Meier Estimate
  • Lung / physiopathology*
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Predictive Value of Tests
  • Prognosis
  • Proportional Hazards Models
  • Pulmonary Disease, Chronic Obstructive / diagnosis
  • Pulmonary Disease, Chronic Obstructive / mortality
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Pulmonary Disease, Chronic Obstructive / therapy
  • Respiration*
  • Risk Factors
  • Severity of Illness Index
  • Walk Test