Outcomes Associated with Initiation of Different Controller Therapies in a Medicaid Asthmatic Population: A Retrospective Data Analysis

Abstract

Background. Outcomes in asthmatic patients may vary depending on the controller medication used. Observational studies of outcomes of asthma therapy are needed to understand the implications of choice of controller in different populations. Objectives. To determine whether there are differences in health care use and costs of asthma treatment in asthma patients treated with montelukast compared with fluticasone proponiate 44 µg. Method. Using data from the North Carolina Medicaid program, we compared continuously enrolled asthmatic patients starting either fluticasone propionate 44 µg (FP44), an inhaled corticosteroid (ICS) (n = 312), or montelukast 5 and 10 mg, an oral leukotriene modifier (LM) (n = 398) between the years 1998 and 1999. A secondary analysis compared continuously enrolled asthmatic patients already using ICS as controller therapy initiating either salmeterol (long-acting β-agonist) (n = 97) or montelukast (n = 101) in the year 1998. Patients were followed for 1 year pre- and postcontroller or additional controller initiation for health care service use, medication refill patterns, and costs. Results. There were no significant differences in the adjusted asthma-related health care costs between the montelukast and FP44 groups. In both groups, physician visits were significantly higher in year 2 (p < 0.01) than in year 1. We found montelukast users to be more adherent with prescription refills (using measures of medication possession) even after allowing for a wider adherence range for FP (RR = 2.53; 95% CI = 1.50–4.26), although patients using montelukast were more likely than patients with fluticasone to switch controller pharmacotherapy (RR = 1.53; 95% CI = 1.12–2.09). Similarly, there were no differences in health care service use and costs between the montelukast and salmeterol groups, with the exception of a 33% reduction (p < 0.01) in number of inhaled corticosteroid refills in the second year in the salmeterol group. Conclusion. There were no cost and major health care use differences between the two primary or secondary controller therapies in the postinitiation year. Although FP was associated with lower rate of controller switch, montelukast use was associated with significantly better treatment adherence in patients with treatment persistence in this population of Medicaid-enrolled asthmatic patients. The addition of salmeterol as additional controller was associated with a significant decrease in inhaled corticosteroid use, suggesting decreased adherence in patients on the two-drug regimen.