CRP and atrial fibrillation: These tools include C-reactive protein (C-RP), the only biomarker recommended by GOLD [9] to evaluate ECOPD severity, and the dyspnea–eosinopenia–consolidation–acidemia–atrial fibrillation (DECAF) prognostic score, which uses several clinical variables (dyspnea, eosinopenia, consolidation, acidemia and atrial fibrillation) to establish the prognosis of severe ECOPD [10].