Fig. 8From: Prognostic risk factors for moderate-to-severe exacerbations in patients with chronic obstructive pulmonary disease: a systematic literature reviewDisease severity as a risk factor for moderate-to-severe exacerbations. Yun 2018 included two studies; the study from which data were extracted (COPDGene or ECLIPSE) is listed in parentheses. Where data have been extracted from a linked publication rather than the primary publication, the linked publication is listed in parentheses. CI confidence interval, ES effect size, FEV1 forced expiratory volume in 1Â s, FVC, forced vital capacity, GOLD Global Initiative for Obstructive Lung Disease, HR hazard ratio, OR odds ratioBack to article page