PT  - JOURNAL ARTICLE
AU  - Maria A Ramon
AU  - Gerben Ter Riet
AU  - Anne-Elie Carsin
AU  - Elena Gimeno-Santos
AU  - Alvar Agustí
AU  - Josep M Antó
AU  - David Donaire-Gonzalez
AU  - Jaume Ferrer
AU  - Esther Rodríguez
AU  - Robert Rodriguez-Roisin
AU  - Milo A Puhan
AU  - Judith Garcia-Aymerich
AU  - the PAC-COPD Study Group
TI  - The dyspnoea-inactivity vicious circle in COPD: Development and external validation of a conceptual model
AID  - 10.1183/13993003.00079-2018
DP  - 2018 Jan 01
TA  - European Respiratory Journal
PG  - 1800079
4099  - http://erj.ersjournals.com/content/early/2018/07/05/13993003.00079-2018.short
4100  - http://erj.ersjournals.com/content/early/2018/07/05/13993003.00079-2018.full
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.Methods: (1)identification and validation of all published vicious circle models by a systematic literature search and fitting structural equation models (SEM) to longitudinal data from the PAC-COPD Spanish cohort (n=210, 68 years, FEV1 54%) testing both the hypothesised relationships between variables in the model (“paths”) and model fit; and (2)development of a new model and external validation using longitudinal data of the Swiss and Dutch ICE COLD ERIC cohort (n=226, 66 years, FEV1 57%).We identified nine vicious circle models for which SEMs 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.FootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Dr. ter Riet has nothing to disclose.Conflict of interest: Dr. Carsin has nothing to disclose.Conflict of interest: Dr. Gimeno-Santos has nothing to disclose.Conflict of interest: Dr. Agusti reports grants and personal fees from Astra-Zeneca, grants and personal fees from GSK, grants from MSD, grants and personal fees from Menarini, personal fees from Novartis, personal fees from TEVA, personal fees from Chiesi, outside the submitted work.Conflict of interest: Dr. Josep M Antó has nothing to disclose.Conflict of interest: Dr. DONAIRE-GONZALEZ has nothing to disclose.Conflict of interest: Dr. Ferrer has nothing to disclose.Conflict of interest: Dr. RODRIGUEZ has nothing to disclose.Conflict of interest: Dr. RODRIGUEZ-ROISIN reports grants from Almirall and Menarini, personal fees from Boehringer Ingelheim, personal fees from Novartis, personal fees from Pearl Therapeutics, personal fees from Takeda, and personal fees from TEVA during the conduct of the study, all related to COPD.Conflict of interest: Dr. Puhan has nothing to disclose.Conflict of interest: Dr. Garcia-Aymerich reports other from AstraZeneca, other from Esteve, other from Chiesi, outside the submitted work.Conflict of interest: Dr. Ramon has nothing to disclose.