This study examined the association between nonadherence to inhaled corticosteroids and risk of an immediate avoidable medical event (emergency department visit and hospitalization) in elderly patients with chronic pulmonary ailments. The study comprised a cross-sectional analysis comparing patients with and without avoidable medical event occurrence in each year for adherence preceding the event, and a case-crossover analysis examining the same patient's adherence in years with and without events. The cross-sectional study showed risk odds reductions of nearly 20% in the partially adherent patient, and 40% in the adherent patient compared to the nonadherent patient, after controlling for potential group differences.