Objective: Compare direct and indirect costs of oxymorphone extended-release ('oxymorphone') and oxycodone controlled-release ('oxycodone') users.
Methods: Patients, aged 18+, with ≥1 claim for oxymorphone/oxycodone, Q2:2006-Q4:2009, were selected from a de-identified private payer claims database and observed from the first such claim ('index date') until the earliest of: use of comparator drug; end of continuous eligibility; 12 months ('study period'). Patients with claims for any formulation of the comparator drug during the first 30 days of the study period were excluded. Direct (medical and drug) costs paid by private insurers were reported for patients aged 18-64 (n = 8354) and 65+(n = 3515), as well as sub-sets without cancer (n = 7090 and n = 2444, respectively). Indirect costs (medically-related absenteeism and disability) were reported for all employees, aged 18-64 (n = 1313), and employees without cancer (n = 1146). Multivariate models were used to estimate risk-adjusted costs controlling for patient characteristics.
Results: Oxymorphone users, aged 18-64, had lower drug costs ($693 vs $763, p = 0.0035) and similar medical costs ($1875 vs $1976, p = 0.3570) per patient-month compared with oxycodone users (mean follow-up 236 and 280 days, respectively). Indirect costs were not different ($662 vs $670, p = 0.9370). Oxymorphone users, aged 65+, had similar Medicare supplemental drug costs ($533 vs $588, p = 0.0840) and lower medical costs ($459 vs $747, p < 0.0001). Results were comparable for subsets without cancer.
Limitations: Patients with concomitant use of oxymorphone and oxycodone were excluded.
Conclusions: Oxymorphone users incur lower risk-adjusted costs in several cost categories, compared with oxycodone users, and no higher costs in any of the examined categories.