History of Adherence as Indicator of Continued Adherence in Asthma Patients

Cincinnati—Approximately 22.2 million Americans are affected by asthma, a chronic respiratory disease. Of the 3 combination therapies available for treatment of uncontrolled moderate to severe persistent asthma, budesonide/formoterol (BFC) and fluticasone/salmeterol (FSC) have a large enough sample size to be included in a recent study. The third combination treatment was mometasone/formoterol (MFC), but due to its recent launch and the small number of patients prescribed treatment with MFC, it was not included in the study.

FSC is usually administered using the ADVAIR DISKUS^®; less commonly with a metered dose inhaler. BFC is administered through SYMBICORT^®, a pressurized metered dose inhaler. Adherence to asthma controller medications may influence prescribing patterns of BFC and FSC, according to researchers, who added that patient history of adherence may be an indicator of future adherence.

The researchers recently conducted a retrospective observation cohort study to evaluate the association between patients’ adherence to prior asthma controller medication and choice of therapy initiation with BFC or FSC. They reported study results during a poster session at the AMCP meeting. The poster was titled Is History of Patient Adherence to Asthma Controller Medication Associated with Initial Choice of Prescription for Inhaled Corticosteroid and Long-Acting Beta2-Adrenergic Agonist Combination Therapy?

The researchers utilized pharmacy and medical claims data from the HealthCore Integrated Research Database between June 1, 2006, and August 31, 2011. The database includes longitudinal claims data from health plans in the Northeast, Midwest, southern, and western regions of the United States.

Inclusion criteria were ≥1 prescription for BFC or FSC any time during the study period; the date of the first prescription was considered the index date. Asthma diagnosis was defined by the presence of ≥1 emergency department visit or inpatient hospitalization with a primary diagnosis of asthma using International Classification of Diseases, Ninth Revision codes or ≥2 medical claims in any setting (inpatients with secondary asthma diagnosis or outpatient) during the 12 months prior to the index date. Patients had to be 12 to 64 years of age on the index date.

Adherence was measured during the 12 months prior to BFC or FSC initiation using medication possession ratio (MPR) for patients with at least 1 preindex asthma controller prescription. Composite-weighted MPR measure, ranging from 0 to 1, was created based on percentage of time each medication was used. Adherence was defined as MPR >0.80.

A total of 38,153 patients initiated combination therapies during the study period (BFC, n=9706; FSC, n=29,975; and MFC, n=472). Compared to patients in the FSC group, a higher percentage of those in the BFC group were prescribed their index medication by a respiratory disease specialist. Patients in the FSC group were more likely to have their prescriptions written by physicians in family/general practice, internal medicine, and other nonrespiratory specialists.

A higher proportion of patients in the BFC group had at least 1 prescription fill during the 12-month preindex period compared with the FSC group for each type of asthma controller medication, including leukotriene receptor antagonist (LTRA) monotherapy (20% vs 19%, respectively), inhaled corticosteroid (ICS) monotherapy (17% vs 13%), and the combination of ICS and LTRA together (9% vs 5%).

A greater proportion of patients in the BFC group had ≥1 prescription fills for ≥1 asthma controller medication during the preindex period compared with the FSC group (47% vs 36%, respectively).

Mean weighted MPR of controller use during the preindex period was similar for both groups and the majority of patients in both groups were adherent to their previous controller medication.

In conclusion, the researchers noted that nearly two thirds of patients in both the FSC (65%) and BFC (64%) were considered adherent to their asthma controller medication therapy during the 12 months prior to initiating combination therapy. Adherence to prior controller therapy in patients with asthma was similar between the 2 groups and “does not appear to have an impact on physician choice of combination therapy initiated.”

This study was supported by AstraZeneca.