Association between previous health care use and initiation of inhaled corticosteroid and long-acting β 2-adrenergic agonist combination therapy among US patients with asthma

Abstract

Background: Combination inhaled corticosteroid and long-acting β 2-adrenergic agonist (ICS/LABA) therapy is recommended for patients whose asthma is not adequately controlled by other maintenance therapies and for those with moderate to severe asthma. Objectives: This study examined the appropriateness of initiation of ICS/LABA combination therapy based on health care use criteria and the proportions of US patients filling prescriptions for either of 2 available therapies. Methods: This retrospective cohort study analyzed data from commercially insured asthma patients aged 12 to 64 years who initiated combination therapy with fluticasone propionate/salmeterol (FSC) or budesonide/ formoterol fumarate dihydrate (BFC) from July 1, 2007, to June 30, 2008. Continuously enrolled patients who had not received ICS/LABA therapy during a 12-month preindex period were assigned to the BFC or FSC cohort based on their initial ICS/LABA prescription (index date). Appropriate initiation of ICS/LABA combination therapy was determined based on the risks for asthma exacerbation, high impairment, and previous controller medication use. Specifically, initiation of ICS/LABA therapy was considered appropriate if patients had claims during the preindex period for an ICS or leukotriene receptor antagonist, an asthma-related emergency department visit or hospitalization, ≥2 courses of oral corticosteroid, or ≥6 canisters of a rescue short-acting β 2-adrenergic agonist (SABA). Factors associated with appropriate initiation of ICS/LABA therapy were assessed by multivariate logistic regression. Results: Of 16,205 patients initiated on ICS/LABA therapy, 39.2% met ≥1 criterion for appropriate use—788 of 1417 patients (55.6%) in the BFC group and 5572 of 14,788 patients (37.7%) in the FSC group ( P < 0.001). Significantly greater proportions of BFC than FSC users met the individual criteria for previous controller medication use (45.7% vs 26.1%, respectively) and high SABA use (9.7% vs 6.1%). BFC users had a significantly higher likelihood of meeting ≥1 appropriateness criterion compared with FSC users (odds ratio = 1.79; 95% CI, 1.60–2.00; P < 0.001). Also significantly associated with appropriate use were receipt of the initial ICS/LABA prescription from a pulmonologist or allergist rather than from a physician in family medicine/general practice ( P < 0.001), residence in the West relative to the Northeast ( P < 0.005), and presence of specific comorbidities (allergic rhinitis, sinusitis, gastroesophageal reflux disease, and acute respiratory infection; all, P < 0.001). Conclusions: Just under 40% of patients met the criteria for appropriate initiation of ICS/LABA therapy, with significantly greater proportions of BFC than FSC users meeting the overall and individual criteria for appropriate use. Patients with appropriate initiation of ICS/LABA therapy were significantly more likely to be treated by pulmonologists and allergists than by family medicine/general practitioners.