Impact of prior and concurrent medication on exacerbation risk with long-acting bronchodilators in chronic obstructive pulmonary disease: a post hoc analysis.

Results suggest that UMEC/VI reduces exacerbation risk versus PBO more consistently across medication subgroups than UMEC or VI, particularly in patients with no/low concurrent medication use. Confirmed prospectively, these findings may support first-line use of dual bronchodilation therapy in symptomatic low-risk patients.