Background: In Australia, as in many other Western countries, patient surveys suggest the costs of medicines lead to deferring or avoiding filling of prescriptions. The Australian Pharmaceutical Benefits Scheme provides approved prescription medicines at subsidised prices with relatively low patient co-payments. The Pharmaceutical Benefits Scheme defines patient co-payment levels per script depending on whether patients are "concessional" (holding prescribed pension or other government concession cards) or "general", and whether they have reached a safety net defined by total out-of-pocket costs for Pharmaceutical Benefits Scheme-approved medicines.
Objective: The purpose of this study was to explore the impact of costs on adherence to statins in this relatively low-cost environment.
Methods: Using data from a large-scale survey of older Australians in the state of New South Wales linked to administrative data from the national medical and pharmaceutical insurance schemes, we explore the relationships between adherence to medication regimes for statins and out-of-pocket costs of prescribed pharmaceuticals, income, other health costs, and a wide set of demographic and socio-economic control variables using both descriptive analysis and logistic regressions.
Results: Within the general non-safety net group, which has the highest co-payment, those with lowest income have the lowest adherence, suggesting that the general safety threshold may be set at a level that forms a major barrier to statin adherence. This is reinforced by over 75% of those who were not adherent before reaching the safety net threshold becoming adherent after reaching the safety net with its lower co-payments.
Conclusion: The main financial determinant of adherence is the concessional/general and safety net category of the patient, which means the main determinant is the level of co-payment.