750Hospital admissions for patients with rheumatoid arthritis in Western Australia hospitals have declined over time

Background Rheumatoid arthritis (RA) imposes a considerable burden on society in terms of morbidity, long-term disability, and costs. RA prevalence is poorly described in Australia, and linked health datasets can provide a more meaningful picture for RA epidemiology in the Australian population. Methods We extracted data on all patients identified in the WA Hospital Morbidity Data Collection between 1995 and 2014, with the International Classification of Diseases (ICD) codes for RA (ICD 10 M05.00–M06.99, and the corresponding ICD 9 codes). We estimated period prevalence rates per 1000 hospital separations and annual average percentage changes, with the total number of hospital separations each year. Results A total of 17,125 patients were admitted to WA hospitals with a diagnostic code for RA over the study period (1995-2014). The total number of hospital separations for RA patients was 50,353, indicating an average of three hospital separations per patient over twenty years. The RA prevalence was 3.4 per 1000 separations over the study period, with a -2.89% annual average decrease since 1995. Conclusion These data demonstrate that hospitalisation for RA has decreased considerably in WA over the last two decades. As this decrease roughly coincides with the introduction of biological drug treatment for RA, the reduced need for hospital admission is likely due to improvements in RA management. Key messages The RA prevalence was 3.4 per 1000 separations over the study period (1995-2014). 750 Table 1:Hospitalisation for Rheumatoid arthritis (RA) in Western Australia (WA) (1995-2014). Year Total RA hospital Separations WA hospital separations RA per 1000 separations Average annual change per annum (RA hospital Separations) Average annual change per annum (WA hospital separations) 1995 3,518 451,195 7.8 0% 0% 1996 3,751 473,677 7.9 7% 5% 1997 3,994 506,721 7.9 6% 7% 1998 3,927 544,566 7.2 −2% 7% 1999 2,785 575,489 4.8 −29% 6% 2000 1,755 612,774 2.9 −37% 6% 2001 1,577 617,891 2.6 −10% 1% 2002 1,685 648,423 2.6 7% 5% 2003 1,908 657,439 2.9 13% 1% 2004 1,836 691,975 2.7 −4% 5% 2005 2,045 714,353 2.9 11% 3% 2006 2,215 740,059 3.0 8% 4% 2007 2,282 783,620 2.9 3% 6% 2008 2,184 829,595 2.6 −4% 6% 2009 2,682 887,209 3.0 23% 7% 2010 2,627 966,033 2.7 −2% 9% 2011 2,597 1,024,462 2.5 −1% 6% 2012 2,689 1,058,751 2.5 4% 3% 2013 2,281 1,070,399 2.1 −15% 1% 2014 2,015 1,081,463 1.9 −12% 1% Total RA hospital separations 50,353 Total WA hospital separations 14,936,094 RA Period