Asthma Medication Ratio Predicts Emergency Department Visits and Hospitalizations in Children with Asthma

Annie Lintzenich Andrews,¹ Annie N. Simpson,² William T. Basco Jr.,¹ Ronald J. Teufel II,¹

Medical University of South Carolina
¹Department of Pediatrics
²Department of Healthcare Leadership and Management

Objective: To determine if the asthma medication ratio predicts subsequent emergency department (ED) visits and hospital admissions in children.
Design: Retrospective cohort with two year pairs.
Setting/Participants: 2007–2009 South Carolina Medicaid recipients with persistent asthma age 2–18.
Main Exposure: Controller-to-total asthma medication ratios were calculated for each patient in 2007 and 2008. Ratios range from 0-1 (1=ideal, 0=no controller).
Outcome Measures: 2008 and 2009 asthma related ED visits, hospitalizations, and a combined outcome of ED visit or hospitalization in the subsequent 3, 6, and 12 month time periods.
Results: 19,512 patients were included. Mean age 8.9 years, 58% male, and 55% black. The ratio significantly predicted ED visits and hospitalizations over subsequent 3, 6, and 12 month time periods. The cut-point that maximized the ability to predict visits ranged from 0.4–0.6. A cut-point of 0.5 was used in the final models. After controlling for age, race, gender, and rurality, patients with a ratio <0.5 were significantly more likely to have a subsequent emergent healthcare visit (OR 1.5–2.0). The ratio retained its predictive ability in both year-pairs for all three outcome variables, in all three time periods, with the exception of the 2008 ratio not predicting 2009 3-month and 6-month hospitalizations.
Conclusions: The asthma medication ratio is a significant predictor of ED visits and hospitalizations in children. Using a cutoff of <0.5 to signal at-risk patients may be an effective way for populations who would benefit from increased use of controller medications to reduce future emergent asthma visits.

Keywords: pediatrics, Medicaid, chronic disease

doi: http://dx.doi.org/10.5600/mmrr.003.04.a05

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