Objectives: The economic impact of switching patterns from older drug treatment for the management of insomnia has not been thoroughly investigated. The objective of this study was to examine the economic burden of therapeutic alterations for the treatment of insomnia.
Methods: Treated insomnia patients were identified from the Medstat Marketscan claims database who had at least one prescription for insomnia agents during the study period (05/01/01 to 11/30/03). A change in therapy was defined as having a recorded prescription for an insomnia treatment other than the index study medication during the post-index period, which included overlapping augmentation or complete therapy switch. Economic costs included direct medical and pharmacy expenditures. One-year follow-up costs were compared using Wilcoxon tests for bivariate analyses and generalized linear models with gamma functions for multivariate comparisons.
Results: Approximately 88% of the sample had no change in insomnia treatment. Patients on monotherapy (n = 24540) differed from patients altering therapy (n = 3267) with respect to age, gender and baseline Deyo-Charlson score. Patients altering therapy had a higher frequency of insomnia diagnoses (22 vs. 11%; p < 0.001) and comorbid depression or anxiety (21-45 vs. 12-25%; p < 0.001) than patients who did not alter therapy. Patients who changed therapy had approximately 67% higher (p < 0.001) direct medical costs compared to those who did not. Limitations of the study include observational study design, and lack of complete availability of all possible risk adjusters for clinical severity.
Conclusion: Total direct medical costs were significantly higher in patients who altered therapy in a year compared to maintainers after controlling for baseline differences.