Fig. 5From: The cutoff point of clinical chronic obstructive pulmonary disease questionnaire for more symptomatic patientsClassification and regression tree analysis of agreement with an SGRQ score ≥ 25 (adjusted by age, sex, body mass index, and FEV1). Abbreviations: FEV1, forced expiratory volume in 1 s; SGRQ, St. George’s Respiratory Disease QuestionnaireBack to article page