ABSTRACT
OBJECTIVE: To assess if dynamic hyperinflation is an independent risk factor for mortality and severe exacerbations in COPD patients. METHODS: A cohort of 141 patients with stable COPD and moderate to very severe airflow limitation, treated according to conventional guidelines, was followed for a median of 9 years. Clinical characteristics were recorded and arterial blood gases, pulmonary function tests, 6-min walk and incremental exercise test with measurement of respiratory pattern and operative lung volumes were performed. Endpoints were all-cause mortality and hospitalization for COPD exacerbation. RESULTS: 58 patients died during the follow-up period (1228 patients x year). The mortality rate was higher in patients with dynamic hyperinflation (n = 106) than in those without it (n = 35) (14.6; 95% CI, 14.5-14.8 vs. 7.2; 95% CI, 7.1-7.4 per 1000 patients-year). After adjusting for sex, age, body mass index, pack-years and treatment with inhaled corticosteroids, dynamic hyperinflation was associated with a higher mortality risk (adjusted hazard ratio [aHR], 2.725; 95% CI, 1.010-8.161), and in a multivariate model, comorbidity, peak oxygen uptake and dynamic hyperinflation were retained as independent predictors of mortality. The time until first severe exacerbation was shorter for patients with dynamic hyperinflation (aHR, 3.961; 95% CI, 1.385-11.328), and dynamic hyperinflation, FEV1 and diffusing capacity were retained as independent risk factors for severe exacerbation. Moreover, patients with dynamic hyperinflation had a higher hospitalization risk than those without it (adjusted incidence rate ratio, 1.574; 95% CI, 1.087-2.581). CONCLUSION: In stable COPD patients, dynamic hyperinflation is an independent prognostic factor for mortality and severe exacerbations.
Subject(s)
Lung , Pulmonary Disease, Chronic Obstructive , Humans , Risk Factors , Comorbidity , Respiratory Function TestsABSTRACT
The syntheses and crystal structures of the two title compounds, C11H10O3 (I) and C17H14BrNO2 (II), both containing the bi-cyclo-[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014 â¸). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bi-cyclo-[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209â (2) and 1.210â (2)â Å, with C-N bond lengths of 1.393â (2) and 1.397â (2)â Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bi-cyclo-[2.2.2]octene ring system. Non-covalent inter-actions present in the crystal structure of II include a number of C-Hâ¯O inter-actions. The extended structure of II also features C-Hâ¯O hydrogen bonds as well as C-Hâ¯π and lone pair-π inter-actions, which combine together to create supra-molecular sheets.
