Fig. 4From: Salbutamol use in relation to maintenance bronchodilator efficacy in COPD: a prospective subgroup analysis of the EMAX trialRisk of a first moderate/severe exacerbation up to Day 168. CI confidence interval, HR hazard ratio, LS least squares, SABA short-acting β2-agonist, SAL salmeterol, UMEC umeclidinium, VI vilanterolBack to article page