A retrospective database study comparing treatment outcomes and cost associated with choice of fixed-dose inhaled corticosteroid/long-acting beta-agonists for asthma maintenance treatment in Germany

Abstract

Aims: This retrospective, observational cohort study aimed to compare treatment outcomes and healthcare costs in the year after initiation of maintenance treatment with budesonide/formoterol or salmeterol/fluticasone in a German healthcare setting.

Methods: Data on German asthma patients initiating treatment with budesonide/formoterol or salmeterol/fluticasone between June 2001 and June 2005 were obtained from the IMS Disease Analyzer database. The primary outcome was the probability of treatment success, defined according to short-acting beta(2)-agonist prescriptions and switches or addition of controller medications, during the postindex year. A secondary definition of treatment success included hospitalisations and oral corticosteroid (OCS) prescriptions. Secondary outcomes included severe asthma exacerbations, defined as >or=1 OCS prescription, asthma-related hospitalisation and/or referral. The effect of treatment on costs was estimated using generalised linear models, adjusting for patient and physician characteristics.

Results: There were no significant differences between the budesonide/formoterol (n = 1456) and salmeterol/fluticasone (n = 982) groups in disease severity markers in the pre-index year. Patients on budesonide/formoterol had a 44% greater probability of treatment success [odds ratio (OR): 1.44; p = 0.0003] according to the primary definition and a 26% greater probability (OR: 1.26; p = 0.0119) according to the secondary definition, fewer severe exacerbations (-33.4%; p = 0.0123) and fewer OCS prescriptions (-31.5%; p = 0.0082) compared with salmeterol/fluticasone, after controlling for baseline characteristics. Adjusting for covariates, budesonide/formoterol had a significant inverse relationship on asthma-related costs compared with salmeterol/fluticasone (-13.4%; p < 0.001). Total cost (asthma- and non-asthma-related costs) was 12.6% lower for budesonide/formoterol (p < 0.0001).

Conclusion: This study suggests that for patients with chronic asthma in Germany, budesonide/formoterol rather than salmeterol/fluticasone had a higher likelihood of treatment success, and that budesonide/formoterol is the less costly option. Although the cohorts appeared to be well matched at baseline, the results should be interpreted with caution given the observational nature of the study.

Figure 1

Selection of patients from the IMS Disease Analyzer database

Figure 2

Proportions of salmeterol/fluticasone- (white bars) or budesonide/formoterol- (black bars) treated patients meeting the criteria for primary (A) or secondary (B) treatment success. p-values calculated via chi-squared test of independence between treatment success and treatment group, for primary success, p = 0.0060 and for secondary success, p = 0.0928

Figure 3

Relative probability of full treatment success. Values to the right of the vertical line indicate a higher probability of full treatment success with budesonide/formoterol compared with salmeterol/fluticasone. The filled circles represent the point estimate for the odds ratios (OR) and the horizontal lines the range of the confidence intervals. The regression models used to derive the adjusted OR included pre-index inhaled corticosteroid (ICS), long-acting β₂-agonist (LABA) and short-acting β₂-agonist (SABA) use for the primary definition and pre-index ICS, LABA and SABA use, age and physician speciality for the secondary definition

Figure 4

Crude comparison of costs in the postindex year between salmeterol/fluticasone- (white bars) and budesonide/formoterol- (black bars) treated patients. p-values were derived using an unequal variance t-test