Figure 1From: Where is the supporting evidence for treating mild to moderate chronic obstructive pulmonary disease exacerbations with antibiotics? A systematic review Number of patients in antibiotic trials. Cumulative number of patients with chronic obstructive pulmonary disease enrolled in placebo-controlled and head-to-head trials evaluating antibiotics in patients with mild to moderate exacerbations from the first published trials until 2005.Back to article page