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 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.

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