Incremental Healthcare Costs and Outpatient Antifungal Treatment of Patients with Aspergillosis in the United States

Objectives: To evaluate the total and outpatient economic burden of aspergillosis, and to describe the outpatient antifungal treatment of aspergillosis within a large, commercially-insured population in the United States. Methods: Adults with at least one medical claim with an aspergillosis diagnosis (International Classification of Disease 9th Revision Clinical Modification [ICD-9-CM] code 117.3 or 484.6) between 07/01/04-03/01/11 were identified from the MarketScan Research Databases. Patients had ≥6 months of pre-index and ≥1 month of post-index continuous health plan and pharmacy benefit enrollment and no pre-index diagnosis of aspergillosis. Aspergillosis cases were propensity score-matched to a sample of controls without aspergillosis. Outpatient antifungal therapy and total and outpatient healthcare resource utilization were evaluated in the post-index period. General linear models were used to estimate costs, which were adjusted by the length of follow-up. Incremental costs were calculated between cohorts and a bootstrap procedure was used to produce corresponding variation and 95% confidence interval estimates. Results: Aspergillosis cases (N=5,499; mean age: 57.8 years; 48.6% female; 64.2% with cancer) were matched to 5,499 controls (mean age: 58.3 years; 48.4% female; 60.6% with cancer). Two-thirds of the aspergillosis cases had no outpatient prescription for an antifungal within 30 days of index; for those with outpatient antifungal therapy, voriconazole was the most commonly prescribed agent (60.9%). Average adjusted total and outpatient expenditures were greater for aspergillosis patients during follow-up than those of the matched controls ($26,680 and $9,248 greater, respectively). Conclusions: The economic burden of aspergillosis is substantial. Patients with aspergillosis utilize significantly more healthcare resources and thus incur greater healthcare costs than do similar patients without aspergillosis.