POS0632 THE LONGITUDINAL ASSOCIATIONS OF METHOTREXATE AND BIOLOGIC USE ON HOSPITAL ADMISSION FOR RHEUMATOID ARTHRITIS PATIENTS IN WESTERN AUSTRALIA POPULATION (1995- 2014)

Abstract

Background:Rheumatoid arthritis (RA) carries a substantial burden for patients and society in terms of morbidity, enduring disability, and costs [1]. The Australian Pharmaceutical Benefits Scheme (PBS) has subsidised biological disease-modifying anti-rheumatic drugs (B-DMARDs) since 2003 [2].Objectives:We examined the impact of B-DMARDs availability on RA hospitalisation rate in the Western Australia (WA) population pre- and post- B-DMARDs introduction to the PBS (1995-2002 and 2003-2014).Methods:Population PBS dispensing data for WA of DMARD were obtained and converted to defined daily doses (DDD)/1000 population/day using the WA population census. RA inpatient records were extracted from the WA Hospital Morbidity Data Collection using ICD-9 codes 714 and ICD-10 codes M05.00–M06.99). Principal component analysis (PCA) was applied to determine the relationship between DMARDs use and RA hospital admission rates.Results:There was a total of 17,125 patients who had 50,353 admissions with a diagnostic code for RA during the study period. DMARD use for RA rose from 1.45 to 3.19 DDD/1000 population/day over 1995-2014 (Figure 1). In 1995-2002, the number of RA admissions fell from 7.9 to 2.6 per 1000 hospital separations, then dropped further from 2.9 to 1.9 per 1000 hospital separations in 2003-2014. Based on PCA analysis, conventional DMARDs (methotrexate) and B-DMARDs dispensing had an inverse association with hospital admissions for RA.Conclusion:The increased availability of conventional and biological DMARDs for RA was associated with a significant decline in hospital admissions for RA patients in WA.