Increased patient co-payments and changes in PBS-subsidised prescription medicines dispensed in Western Australia

Objective: To determine whether a 24% increase in patient co-payments in January 2005 and two related co-payment changes for medicines subsidised under the Australian Pharmaceutical Benefits Scheme (PBS) were associated with changes in dispensings in Western Australia (WA). Method: We analysed aggregate monthly prescription counts and defined daily dose per 1,000 population per day (DDD/1,000/day) for atypical antipsychotics, combination asthma medicines, HmgCoA reductase inhibitors (statins) and proton-pump inhibitors (PPIs). Trends pre and post the co-payment increase in January 2005 were compared. Results: In three of the four categories examined, prescription counts were significantly lower following the increase in co-payment thresholds. Compared with dispensings prior to the co-payment increase, prescriptions fell by 8% for combination asthma medicines (p<0.001), 9% for PPIs (p<0.001) and 5% for statins (p<0.001). Following the rise in copayments, DDD/1,000/day decreased for all four categories. Decreases in dispensings to concessional beneficiaries were between 4% and 5% larger than for general beneficiary patients. Conclusions and Implications: The reduction in the both prescription counts and DDD/1,000/day observed for combination asthma medicines, PPIs and statins, which all remained above co-payment thresholds, suggests the increase in PBS co-payments has affected utilisation of these subsidised medicines. The results indicate that increases in patient contributions particularly impact on concessional patients' ability to afford prescription medicines.