Estimated effect of asthma case management using propensity score methods.

OBJECTIVE

To estimate the treatment effect of participation in an asthma intervention that was part of the National Asthma Control Program.

STUDY DESIGN

Cross-sectional; difference in outcomes between participants and comparable nonparticipants matched by using propensity scores.

METHODS

Data on children who participated in asthma case management (n = 270) and eligible children who did not participate in case management (n = 2742) were extracted from a Medicaid claims database. We constructed measures of healthcare utilization, sociodemographics, and neighborhood characteristics. After creating a comparison group similar to the participants in terms of all characteristics before participation, we estimated the effect of the program on asthma outcomes.

RESULTS

Participants were more likely to have vaccinations for pulmonary illness (95% confidence interval [CI] = 1.82, 4.81), to fill a prescription for controller medications (95% CI = 1.07, 2.19), and to have a refill for rescue medication (95% CI = 1.07, 2.07) after the program than comparable nonparticipants. There was no statistically significant difference in the number of nebulizer treatments or emergency department visits between the 2 groups.

CONCLUSIONS

The program did increase the use of preventive healthcare by participants. Over the time period we studied, these behaviors did not decrease healthcare utilization for asthma exacerbations. We were unable to discern whether the lack of effect was because of the nature of the program, heterogeneity of the effects, or barriers outside the program's control.