Fig. 6From: Measuring disease activity in COPD: is clinically important deterioration the answer?Summary of the CID concept. awithin 12 to 24 weeks. CID, clinically important deterioration; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; SGRQ, St George’s Respiratory QuestionnaireBack to article page