OBJECTIVES

Depression is a major comorbidity affecting asthma management. Inefficient asthma control has been shown to result in increased Emergency Department (ED) visits/hospitalizations. Poor adherence to asthma medications is an underlying cause responsible for poor asthma control. Study objectives were to compare medication adherence to asthma controller medications between beneficiaries with and without comorbid depression and to measure the healthcare resource utilization among Mississippi Division of Medicaid (DOM) beneficiaries.

METHODS

A retrospective cohort study of asthma patients with and without depression between 18-64 years of age using DOM claims data for the period January 2015 – June 2017 was conducted. Medication adherence was calculated as the proportion of days covered (PDC) during the 6-month period following the first prescription fill for an asthma controller medication after January 1, 2015. An 80% PDC cut-off limit was used to identify adherent and non-adherent beneficiaries. Asthma-related ED visits and hospitalizations occurring during the same period were identified. Modified Poisson regression was performed to calculate the relative risk of ED visits and hospitalizations between asthma beneficiaries with and without depression.

RESULTS

A total of 3,434 beneficiaries were included and 483 (14.1%) had comorbid depression. No significant difference was seen in medication adherence among asthma beneficiaries with and without depression. Beneficiaries with asthma and depression had a greater risk of asthma-related ED visits (Risk Ratio [RR] 1.33, 95% Confidence Interval [CI]: 1.20 – 1.46, p < 0.001) and asthma-related hospitalizations (RR 2.79, 95% CI: 1.75 – 4.44, p < 0.001) as compared to beneficiaries without depression.

CONCLUSIONS

Depression was not associated with decreased adherence but was associated with increased healthcare resource utilization. Medication adherence may not be a good indicator of depression burden in asthma by itself; a better understanding might be obtained by measuring healthcare resource utilization in addition to medication adherence.