Measuring the cost of poor asthma control and exacerbations.

BACKGROUND

Previous studies have shown an association between cost and poor asthma control. However, longitudinal studies of general populations are lacking.

OBJECTIVE

To examine the cost of poor asthma control and exacerbations across a broad spectrum of asthma patients.

METHODS

The Observational Study of Asthma Control and Outcomes (OSACO) was a prospective survey of persistent asthma patients in Kaiser Colorado in 2011-2012. Patients received a survey 3 times in one year, which included the Asthma Control Questionnaire (ACQ) and questions on exacerbations. Self-reported exacerbations were compared to actual oral corticosteroid (OCS) use. Regression analyses examined the association of control (ACQ-5 scores) and exacerbations with healthcare expenditures, controlling for sociodemographics and smoking. Analyses of expenditures used Generalized Linear Models (GLM) with log-link.

RESULTS

2681 individuals completed at least one survey; 1799 completed all three. ACQ-5 scores were associated with higher all-cause and asthma-specific expenditures across all categories of costs (medical, outpatient, ER, pharmacy) except for inpatient expenditures. Each 1-point increase in the ACQ-5 score (i.e., worse control) was associated with a corresponding increase in all-cause annual healthcare and asthma-specific expenditures of $1443 and $927 ($US 2013). Asthma exacerbations with documented OCS use were associated with an increase of $3014 and $1626 over 4 months, while self-reported exacerbations were $713 and $506.

CONCLUSION

Results demonstrate that poor asthma control and exacerbations are strongly associated with higher healthcare expenditures. Results also confirm that collection of validated measures of control such as the ACQ-5 may provide valuable information toward improving clinical and economic outcomes.