Long-term outcomes after stepping down asthma controller medications: A claims-based, time-to-event analysis

BACKGROUND: Long-term outcomes after stepping down asthma medications are not well described. METHODS: This study was a retrospective time-to-event analysis of individuals diagnosed with asthma who stepped down their asthma controller medications using a US claims database spanning 2000 to 2012. Four-month intervals were established and a step-down event was defined by a ≥ 50% decrease in days-supplied of controller medications from one interval to the next; this definition is inclusive of step-down that occurred without health-care provider guidance or as a consequence of a medication adherence lapse. Asthma stability in the period prior to step-down was defined by not having an asthma exacerbation (inpatient visit, ED visit, or dispensing of a systemic corticosteroid linked to an asthma visit) and having fewer than two rescue inhaler claims in a 4-month period. The primary outcome in the period following stepdown was time-to-first asthma exacerbation. RESULTS: Thirty-two percent of the 26,292 included individuals had an asthma exacerbation in the 24-month period following step-down of asthma controller medication, though only 7% had an ED visit or hospitalization for asthma. The length of asthma stability prior to stepping down asthma medication was strongly associated with the risk of an asthma exacerbation in the subsequent 24-month period: < 4 months' stability, 44%; 4 to 7 months, 34%; 8 to 11 months, 30%; and ≥ 12 months, 21% ( P < .001). CONCLUSIONS: In a large, claims-based, real-world study setting, 32% of individuals have an asthma exacerbation in the 2 years following a step-down event.