Relationship of asthma control to asthma exacerbations using surrogate markers within a managed care database

To compare the relationship of surrogate markers of asthma control to subsequent asthma exacerbations.

Retrospective cohort.

Administrative data were used to identify patients who met the Healthcare Effectiveness Data and Information Set (HEDIS) criteria for persistent asthma in 2006 and 2007. The following potential surrogate markers of asthma control assessed in 2007 were compared for their ability to predict asthma exacerbations in 2008 (defined as oral corticosteroid dispensing or an asthma hospitalization or emergency department visit): dispensing of any controller, unweighted medication ratio (the ratio of controller to total medication), weighted medication ratio, and the number of short-acting beta-agonist (SABA) canisters dispensed. Weighted medication ratios were weighted for controller potency and for doses per container.

Meeting the HEDIS criteria for persistent asthma were 8634 patients (60.5% female) aged 18 to 56 years (mean age, 42.7 years), of whom 6.5% experienced emergency hospital care and 27.3% received oral corticosteroids in 2008. The largest effect size for predicting reduced emergency hospital care was for the number of SABA canisters dispensed (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.40-0.60), followed by the unweighted medication ratio (OR, 0.54; 95% CI, 0.40-0.72), and then the weighted medication ratio (OR, 0.57; 95% CI, 0.45-0.73). Dispensing of any controller was associated with a nonsignificant increased risk of emergency hospital care (OR, 1.41; 95% CI, 0.95-2.09).

The number of SABA canisters dispensed is most strongly related to improved asthma outcomes, followed by the unweighted medication ratio; dispensing of any controller is least related. Health plans can use the number of SABA canisters dispensed and the unweighted medication ratio for asthma population management or for provider quality-of-care assessment to reduce asthma exacerbations, which exact a high economic and humanistic cost.