Stratifying asthma populations by medication use: how you count counts

Quarterly assessment of short-acting beta(2)-adrenergic agonist use as a predictor of subsequent health care use for asthmatic patients in the United States

PURPOSE

An annual time frame for risk assessment may not account for the variable course of asthma. The purpose of this study was to determine whether excessive short-acting beta(2)-adrenergic agonist (SABA) dispensed quarterly was associated with asthma exacerbations in the subsequent quarter.

PATIENTS AND METHODS

This retrospective cohort analysis included 93,604 health plan members aged 6-56 years with >or=2 years of continuous enrollment (2003-2007), an asthma diagnosis, and asthma prescription claims. The amount of SABA dispensed in claims (metered-dose inhaler and nebulized) was converted to canister equivalents (CEs) in the first observation quarter and categorized as 0, 0.5-3, and >or=3 (excessive SABA use). Asthma exacerbation risk (hospitalization, emergency department [ED] visit, or oral corticosteroid [OCS] claim in the subsequent quarter) was assessed using logistic regression. Covariates used in the regression models were age, sex, geographic region, comorbidities, specialist consultation, asthma controller medication use, and asthma severity.

RESULTS

The cohort included 33,951 patients aged 6-17 years (36%) and 59,653 aged 18-56 years (64%); 64% had 0 SABA CE, and 5% had >3 SABA CEs. Compared with 0 CE, excessive SABA use (>3 CEs) was associated with an increased likelihood of hospitalization (adjusted odds ratio [OR]: 3.15, 95% confidence interval [CI]: 1.89-5.27) and an ED/urgent care (UC) visit (adjusted OR: 3.14, 95% CI: 2.32-4.28).

CONCLUSION

The risk of an asthma exacerbation was associated with excessive SABA use in the previous quarter. Assessment of excessive SABA dispensed during a calendar quarter can be used to identify patients at increased exacerbation risk in the subsequent quarter.

Evaluation of asthma prescription measures and health system performance based on emergency department utilization

BACKGROUND

Measures based on the use of either antiinflammatory and/or reliever medications have been used to evaluate clinical performance in asthma.

OBJECTIVE

We compared the association between 2 asthma prescription measures (APMs) and subsequent risk of emergency department (ED) asthma visits.

DESIGN

We conducted a cross-sectional analysis of automated pharmacy and healthcare utilization data from 3 large geographically diverse managed care organizations.

PARTICIPANTS

We studied children, 3 to 15 years of age, with at least 1 encounter for asthma (hospitalization, ED, or ambulatory care), at least 1 dispensing of an asthma medication, and continuous enrollment between June 1996 and July 1997.

MEASURES

Two performance measures were derived for patients with persistent asthma: 1) the proportion of individuals who have received controller therapy and 2) the ratio of dispensed controller to dispensed reliever medications. Children with persistent asthma were identified using the Health Employers Data Information System (HEDIS) criteria of the National Committee on Quality Assurance definition. Multivariate logistic regression was used to assess independent effects in models for ED visits.

RESULTS

Among children with persistent asthma, the dispensing of a controller was associated with a significantly lower risk of an ED visit as compared with children not dispensed a controller (odds ratio, 0.3; 95% confidence interval, 0.2-0.4). An association between the ratio of controller to reliever dispensing and the risk of subsequent ED visit was also observed, however, the underlying level of reliever dispensing modified the relationship. Among children with persistent asthma, the ratio of controller to reliever dispensing was inversely associated with risk of ED visit among children dispensed <4 relievers/person-year but no significant relationship was seen among children dispensed > or =4 relievers/person-year.

CONCLUSION

Among children with persistent asthma, the use of an asthma prescription measure (APM) can help stratify children based on their risk of future adverse events. The HEDIS measure, the dispensing of a controller medication among a population with persistent asthma, and the controller to reliever ratio are associated with the risk of subsequent ED visit. However, the association between the ratio measure and risk for ED visit is modified by the underlying level of reliever dispensing.