PT  - JOURNAL ARTICLE
AU  - Ramon, Maria A.
AU  - Ter Riet, Gerben
AU  - Carsin, Anne-Elie
AU  - Gimeno-Santos, Elena
AU  - Agustí, Alvar
AU  - Antó, Josep M.
AU  - Donaire-Gonzalez, David
AU  - Ferrer, Jaume
AU  - Rodríguez, Esther
AU  - Rodriguez-Roisin, Robert
AU  - Puhan, Milo A.
AU  - Garcia-Aymerich, Judith
ED - 
TI  - The dyspnoea–inactivity vicious circle in COPD: development and external validation of a conceptual model
AID  - 10.1183/13993003.00079-2018
DP  - 2018 Sep 01
TA  - European Respiratory Journal
PG  - 1800079
VI  - 52
IP  - 3
4099  - https://publications.ersnet.org//content/52/3/1800079.short
4100  - https://publications.ersnet.org//content/52/3/1800079.full
SO  - Eur Respir J2018 Sep 01; 52
AB  - The vicious circle of dyspnoea–inactivity has been proposed, but never validated empirically, to explain the clinical course of chronic obstructive pulmonary disease (COPD). We aimed to develop and validate externally a comprehensive vicious circle model.We utilised two methods. 1) Identification and validation of all published vicious circle models by a systematic literature search and fitting structural equation models to longitudinal data from the Spanish PAC-COPD (Phenotype and Course of COPD) cohort (n=210, mean age 68 years, mean forced expiratory volume in 1 s (FEV1) 54% predicted), testing both the hypothesised relationships between variables in the model (“paths”) and model fit. 2) Development of a new model and external validation using longitudinal data from the Swiss and Dutch ICE COLD ERIC (International Collaborative Effort on Chronic Obstructive Lung Disease: Exacerbation Risk Index Cohorts) cohort (n=226, mean age 66 years, mean FEV1 57% predicted).We identified nine vicious circle models for which structural equation models confirmed most hypothesised paths but showed inappropriate fit. In the new model, airflow limitation, hyperinflation, dyspnoea, physical activity, exercise capacity and COPD exacerbations remained related to other variables and model fit was appropriate. Fitting it to ICE COLD ERIC, all paths were replicated and model fit was appropriate.Previously published vicious circle models do not fully explain the vicious circle concept. We developed and externally validated a new comprehensive model that gives a more relevant role to exercise capacity and COPD exacerbations.An externally validated model highlights exercise capacity and exacerbations as drivers of the COPD vicious circle http://ow.ly/NXvu30kW7CP