Patterns in use and costs of conventional and biologic disease-modifying anti-rheumatic drugs in Australia

Objective The aim of this study was to characterise the use and costs of subsidising conventional disease-modifying anti-rheumatic drugs (DMARDs) and biologic DMARDs in Australia from 2004-2014 through pharmaceutical benefits schemes. Methods Dispensing and expenditure data on conventional and biologic DMARDs were extracted from Medicare Australia and temporal trends were analysed. Medicine use was standardised in terms of the defined daily dose (DDD) per 1,000 population per day (DDD/1,000 population/day). Results Conventional and biologic DMARD use increased 74% over the study period (4.86 to 8.46 DDD/1,000 population/day; average annual increase 6.7%). Conventional DMARDs accounted for the vast majority of total use and increased 55% (4.81 to 7.43 DDD/1,000 population/day), while biologic DMARD use increased 1,784% (0.055 to 1.030 DDD/1,000 population/day). The most frequently used conventional DMARD was methotrexate (56% total conventional DMARD use) and use increased 95%. Hydroxychloroquine and leflunomide use increased marginally while sulfasalazine use declined 4.2%. Etanercept was the most commonly used biologic DMARD in 2004 and adalimumab in 2014. Conventional DMARD expenditure decreased 4.2% to AUD$33.3 million but biologic DMARD expenditure increased 2,089% to AUD$585.4 million. Conclusion The use of conventional and biologic DMARDs increased substantially over a decade in Australia. Patterns of use of conventional DMARDs have changed, and costs have decreased. In contrast a significant escalation in both the use and cost of biologic DMARDs has occurred. Further research is required to address cost-effectiveness, regulation and quality use of these medicines in clinical practice.