OP0095 NON-GONOCOCCAL PYOGENIC ARTHRITIS OF NATIVE JOINTS IN WESTERN AUSTRALIA. A LONGITUDINAL POPULATION-BASED STUDY OF FREQUENCY, RISK FACTORS AND OUTCOME.
Authors: J. Nossent, W. Raymond, D. Preen, H. Keen, C. Inderjeeth
Journal: Annals of the Rheumatic Diseases (2021)

Background: The worldwide incidence of PyA is reportedly rising due to a combination of increased longevity, multi- comorbidity, iatrogenic complications and increasing use of immunomodulating therapies, while there is limited data on longterm outcomes of PyA. Objectives: To describe the recent incidence, risk factors and long-term outcomes in adults hospitalised with non-gonococcal pyogenic arthritis (PyA) of native joints in Western Australia (WA). Methods: We extracted population-based longitudinally linked administrative health data for patients 16 years or older with a first diagnostic code of 711.xx (ICD9-CM) and M00.xx (ICD10-AM) in WA in the period 1990-2010. Annual incidence rates (IR), risk factors during 14.5 years lookback and outcomes including standardized mortality rates (SMR) during 10.1 years follow-up are reported. Results: A total of 2,777 patients (67% male, mean age 49.8 ± 20.5) received a first diagnostic code for PyA. The AIR increased from 4.5 to 11.8 /100,000 over time as did age at onset (45.1 to 55.4 years) and proportion of female patients (23 to 36%). There was no seasonal variation in PyA incidence but a higher rate of predisposing comorbidities in female patients. Knees (33.6%) and hands (22%) were most frequently affected with 28.4 % of positive cultures not due to Gr+ cocci. Mean hospital stay was 8 days, 30-day readmittance and mortality rate was 12 .8% and 3.1% respectively. During ten years follow-up serious infections (43%), new diagnosis of osteoarthrosis (20%), joint replacement (10.8%), osteomyelitis (6%), and crystal arthropathy (6.3%) were the most common morbidities. SMR were increased across all age and gender categories (Table) but highest in females aged 16-40 (SMR 25.9). Table 1. Mortality rates (MR) per 1000 person years in patients with pyogenic arthritis compared with age (at death) and gender matched categories from the general population by standardised mortality rate (SMR) Gender Age Deaths Person years MR PyA MR Gen pop * SMR Male 16-40 27 4015 6.72 0.892 7.53 40-59 80 7106 11.25 2.972 3.78 &gt;60 331 7366 44.93 21.55 2.08 All 438 18487 23.69 5.820 4.07 Female 16-40 11 1026 10.72 0.41 25.95 40-59 40 2769 14.44 1.75 8.21 &gt;60 208 4088 50.88 24.20 2.10 All 259 7883 32.85 5.50 5.96 * Based on WA death data from Australian Bureau of statistics in 2011 Conclusion: The incidence of PyA has increased significantly between 1990 and 2010 in WA. PyA associates with a 3% in-hospital mortality rate and significant late bone and joint morbidity including osteomyelitis. PyA associated with excess mortality across age and gender categories, most markedly in younger female patients. References: [1]Ross JJ. Septic arthritis of native joints. Infect Dis Clin North Am 2017;31:203-18 Acknowledgements: The authors would like to acknowledge the support of the Western Australian Data Linkage Branch, the Western Australian Department of Health, and the data custodians of, the Hospital and Morbidity Data Collection, the Emergency Department Data Collection the WA Cancer Register and the WA Death Register for their assistance with the study Disclosure of Interests: None declared