The impact of reference pricing of nonsteroidal anti-inflammatory agents on the use and costs of analgesic drugs

Abstract

Objective: To estimate the effect of reference pricing (RP) of nonsteroidal anti-inflammatory drugs (NSAIDs) on drug subsidy program and beneficiary expenditures on analgesic drugs.

Data sources/study setting: Monthly claims data from Pharmacare, the public drug subsidy program for seniors in British Columbia, Canada, over the period of February 1993 to June 2001.

Study design: RP limits drug plan reimbursement of interchangeable medicines to a reference price, which is typically equal to the price of the lowest cost interchangeable drug; any cost above that is borne by the patient. Pharmacare introduced two different forms of RP to the NSAIDs, Type 1 in April 1994 and Type 2 in November 1995. Under Type 1 RP, generic and brand versions of the same NSAID are considered interchangeable, whereas under Type 2 RP different NSAIDs are considered interchangeable. We extrapolated average reimbursement per day of NSAID therapy over the months before RP to estimate what expenditures would have been without the policies. These counterfactual predictions were compared with actual values to estimate the impact of the policies; the estimated impacts on reimbursement rates were multiplied by the postpolicy volume of NSAIDS dispensed, which appeared unaffected by the policies, to estimate expenditure changes.

Principal findings: After Type 2 RP, program expenditures declined by $22.7 million (CAN), or $4 million (CAN), annually cutting expenditure by about half. Most savings accrued from the substitution of low-cost NSAIDs for more costly alternatives. About 20 percent of savings represented expenditures by seniors who elected to pay for partially reimbursed drugs. Type 1 RP produced one-quarter the savings of type 2 RP.

Conclusions: Type 2 RP of NSAIDs achieved its goal of reducing drug expenditures and was more effective than Type 1 RP. The effects of RP on patient health and associated health care costs remain to be investigated.

Figure 1

Days of Analgesic Therapy Dispensed per 1,000 Seniors, by Analgesic Type and Month

Figure 2

Average Expenditure per Day of NSAID Therapy Dispensed, by Month and Payer (Pharmacare and Patients)

Figure 3

Days of NSAID Therapy Dispensed per 1,000 Seniors, by NSAID Reimbursement Category and Month

Figure 4

Patient Out-of-Pocket Drug Expenditures per 1,000 Seniors, by Analgesic Category and Month

Figure 5

Average Retail Unit Prices of NSAIDs, by Their Type 2 RP Reimbursement Status and Month