June 2007

Document Type


Degree Name



Dept. of Public Health and Preventive Medicine


Oregon Health & Science University


The purpose of this study was to evaluate the impact of changes in prescription practices related to Oregon's Practitioner Managed Prescription Drug Plan (PMPDP) on emergency department (ED) visits and hospitalizations for persons receiving long-acting opioid analgesics for non-cancer pain. Pharmacy and medical reimbursements claims from Oregon's Medicaid fee-for-service were used to investigate the impacts of this policy change. We established an open-cohort of continuous long-acting opioid users treated for non-cancer pain during the year prior to implementation of the PMPDP prescription practices guidelines. The cohort was separated into two groups: switchers and non-switchers. Switchers were defined as those persons who received an opioid not listed on the preferred drug list prior to policy implementation and who switched to an opioid listed on the formulary after policy implementation. Subgroups were defined by time period of switch. Non-switchers were defined as persons who received opioid prescriptions prior to policy implementation and were not switched to an opioid listed on the formulary after policy implementation. For the year period preceding PMPDP policy implementation and the year following its prohibition, ED visits and hospitalizations were quantified and changes in service use were compared. A difference-in-differences analysis was performed between defined time periods to assess changes associated with the policy. Sensitivity analyses were conducted for the subgroups and aggregate analyses were conducted for all opioid users combined. Results indicate that ED visits and hospitalizations were not different in individuals subject to prescription changes due to the PMPDP policy compared to persons not affected by the formulary.




School of Medicine



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