Fig. 4From: Can roflumilast, a phosphodiesterase-4 inhibitor, improve clinical outcomes in patients with moderate-to-severe chronic obstructive pulmonary disease? A meta-analysisEffects of roflumilast vs. placebo on prebronchodilator FEV1. CI, confidence interval; FEV1, forced expiratory volume in one second; SD, standard derivationBack to article page