Insurance status and asthma-related health care utilization in patients with severe asthma.

BACKGROUND: Medicaid insurance has been associated with worse asthma outcomes, but the degree to which demographic factors contribute to this relationship has not been well explored. OBJECTIVE: To evaluate whether insurance status is independently associated with health care utilization (HCU) and asthma control when demographic differences are taken into account. METHODS: We used baseline data from adults with severe asthma in the Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens study. HCU was defined as hospitalization or emergency department visit for asthma in the past 3 months. Asthma control was evaluated using the Asthma Therapy Assessment Questionnaire. Multiple logistic regression was used to compare HCU and asthma control in patients with Medicaid vs those with private health insurance. RESULTS: Of 1315 patients analyzed, 130 (9.9%) had Medicaid insurance and 1,185 (90.1%) had private insurance. Medicaid insurance was associated with younger age, female sex, race other than white, obesity, active smoking, lower education level, and unemployment. In unadjusted analyses, Medicaid patients had significantly higher HCU (odds ratio OR], 3.08; 95% confidence interval CI], 2.11-4.50) and poorer asthma control (OR, 2.56; 95% CI, 1.84-3.57) compared with patients with private insurance. After adjusting for demographic differences, insurance status was no longer associated with HCU (OR, 1.43; 95% CI, 0.92-2.23), and the strength of its association with asthma control was reduced (OR, 1.67; 95% CI, 1.17-2.40). CONCLUSIONS: Medicaid insurance is not associated with increased HCU in patients with severe asthma once demographic factors have been taken into account but remains modestly associated with poorer asthma control.