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Background To determine the global prevalence of rheumatoid arthritis (RA) based on published studies and reveal factors which influence the RA prevalence estimates. Methods Four electronic databases- ProQuest Central, MEDLINE, Web of Science, and EMBASE were searched for publications from 1980 and 2019, reporting prevalence estimates of RA. A random-effect meta-analysis model was used to produce the pooled prevalence estimates. The potential sources of between-study heterogeneity were identified using sensitivity analysis, sub-group and meta-regression analyses. Results A total of 67 studies consisting of 212,335,171 patients were included in the meta-analysis. The global prevalence of RA was estimated 0.46% (95% CI: 0.39-0.54; I2=99.9%) with a 95% prediction interval (0.06–1.27). The point-prevalence of RA was 0.45% (95% CI: 0.38- 0.53%), while the pooled period-prevalence was 0.46% (0.36% and 0.57%). The highest RA pooled prevalence was estimated at 0.69% (95% CI: 0.47–0.95) derived from linked data sources studies. Based on subgroup analyses, the pooled prevalence of RA was influenced by geographical location, the risk bias of studies, period-prevalence method and urban population setting over the stratified periods. Conclusion The global prevalence of RA was 460 per 100,000 population from 1980–2018, with a 95% prediction interval (0.06– 1.27%). RA prevalence estimates were influenced by geographical location, the risk bias assessment of studies, period-prevalence method and urban population setting over time. Key messages The global prevalence of RA was 460 per 100,000 population from 1980–2018, with a 95% prediction interval (0.06– 1.27%).

SummaryDuring a 5-year period 131 patients with symptomatic deep venous thrombosis of the lower extremities (DVT) were identified in a black Caribbean population. Eighty-one patients (61%) had objective evidence (ascending venography), while in 39% the diagnosis was based on clinical findings only. The overall annual incidence rate for definite DVT was 11 per 100,000 person years; there was a steep increase with age in both sexes. Proximal DVT was present in 69% of patients. Swelling (92%), pain on palpation (89%) and tenderness (87%) were the most frequent symptoms, while immobilization (43%) and varicosities (42%) were the most frequent risk factors; DVT was rare during pregnancy (1 in 15,000 deliveries). Seventeen patients (21%) developed pulmonary embolism and five patients (6.2%) died during the hospital stay (four of fatal pulmonary embolism, one due to toxic epidermolysis after venography). We conclude, that symptomatic DVT of the lower extremities has a low incidence in this black Caribbean population, but is nonetheless associated with considerable morbidity and mortality due to pulmonary embolism.

Background:Rheumatoid arthritis (RA) contributes to excess morbidity and mortality in RA patients compared with the general population (1). In Australia, there is a paucity of published literature on the mortality and morbidity rates in RA patients, despite the significant morbidity and mortality burden on health care costs due to RA. Linked data is the preferred method to estimate morbidity and mortality outcomes as they provide the best case-ascertainment.Objectives:To describe temporal changes in mortality rates for patients with RA in relation to comorbidity accrual from 1980-2015 in Western Australia (WA).Methods:Using population-level linked data from WA health administrative datasets (hospital morbidity, emergency department and death data) we followed 17,125 RA patients (ICD-10-AM M05.00–M06.99, ICD-9-CM 714) from 1980- 2015. Comorbidity was ascertained using the Charlson Comorbidity Index (CCI). Mortality rate ratios (MRR) were calculated per decade between the RA cohort and the WA general population by direct age standardisation method, while temporal trends of comorbidities and in-hospital mortality were estimated per 1000 hospital separations in three consecutive decades.Results:During 356,069 patient-years, a total of 8955 (52%) deaths occurred in the RA cohort. The leading causes of deaths were cardiovascular diseases 2386 (26.6%), cancer 1511 (16.8%), rheumatic diseases 519 (5.8%), chronic pulmonary disease 491 (5.5%), dementia 269 (3.0%) and diabetes 235 (2.6%). The highest prevalence of comorbidity (688.6 per 1000 separations) was in the period 1991-2000 following a 1.3% average annual increase since 1980. In-hospital mortality rate was also highest (26.7 deaths per 1000 separations) in the same period. After 2001, both RA comorbidity and mortality rates decreased annually by -0.5% and -4.8%, respectively, with annual changes of -4.4% to -2% and from 2011- 2015, respectively. The overall mortality rate in RA patients after age adjustment was 2.5-times (95%CI: 2.52-2.65) higher than the general population between 1980- 2015 and 1.5-times (95%CI: 1.39-1.81) for the period 2011-2015.Conclusion:The annual comorbidity prevalence and mortality rates in WA have decreased significantly since 2001 reflecting improvements in the management of RA and comorbidity. Nonetheless, the mortality rate in RA patients in WA remains 1.5-times higher than their community counterparts suggesting that there is room to achieve further improvements.References:[1]Meune C, Touze E, Trinquart L, Allanore Y (2009) Trends in cardiovascular mortality in patients with rheumatoid arthritis over 50 years: a systematic review and meta-analysis of cohort studies. Rheumatology (Oxford) 48:1309-1313. doi:10.1093/rheumatology/kep252Table 1.Mortality rates observed among patients with rheumatoid arthritis, based on Charlson Comorbidity Index, per 1000 hospital separations, Western Australia hospitals (1980-2015).Time period1980-19901991-20002001-20102011-2015Total number of hospital separations8209910773118539880410Number of deaths1620287531831277CCI score0481 (29.7%)1024 (35.6%)1197 (37.6%)565 (44.2%)1838 (51.7%)1271 (44.2%)1358 (42.6%)467 (36.6%)2273 (16.8%)518 (18%)581 (18.3%)232 (18.2%)31 (0.1%)4 (0.2%)2 (0.1%)0 (0%)627 (1.7%)58 (2%)45 (1.4%)13 (1%)In-hospital RA mortality per 1000 hospital separation19.726.717.215.9Parentage of average annual change per annum in the period03.8-4.8-2.6Parentage of average annual change since 198001.5-1.4-0.2CCI= Charlson Comorbidity Index.Acknowledgements:Khalid Almutairi was supported by an Australian Government Research Training Program PhD Scholarship at the University of Western Australia.Disclosure of Interests:Khalid Almutairi: None declared, Johannes Nossent Speakers bureau: Janssen, David Preen: None declared, Helen Keen Speakers bureau: Pfizer Australia, Abbvie Australia, Charles Inderjeeth Speakers bureau: Eli Lilly.

Background Immunocompromised patients are inherently vulnerable to severe outcomes to vaccine preventable infections compared to the general population. This study aims to investigate the impact of immunosuppression on response to the ChAdOx1nCov-19 and BNT162b2 vaccines to better inform vaccination efforts in this cohort. Methods A three-armed randomised controlled trial was performed. Patients with autoimmune disorders on immunosuppressive therapies and healthy controls were recruited from two sites. Participants receiving immunosuppression were randomly assigned to either withhold or continue treatment contemporaneous to vaccine administration. Serum SARS-Cov2 immunoglobulin assays were performed at baseline and, 4-weeks following first and second vaccine doses. Between group comparisons were performed to examine differences in vaccine seroconversion and immunogenicity. Results A total of, 253 participants of median age, 55 years (IQR:, 45.5–64) including, 193 patients receiving immunosuppression and, 60 healthy controls were studied. Immunosuppressed patients were randomly allocated to continue (n=105) or withhold (n=88) treatment. Of those receiving immunosuppression, 27.08%, 40.63% and, 32.29% of patients were exposed to cDMARDs, bDMARDs and tsDMARDs respectively while rates of BNT162b (Pfizer) vaccination were, 52.33%, 60.67% and, 48.33% among the continue, withhold, and control groups respectively. Post-first dose vaccination seroconversion rates were highest among healthy controls (90%) and patients who temporarily withheld immunosuppressants (76.32%) compared to patients continuing treatment (48.24%) p=0.000. Post-second dose vaccination seroconversion rates were, 100% in both the control and withhold groups and, 86.75% in the continuation (p=0.001). Mean quantitative serum SARS-CoV-2 IgG titres were, 8.58 U/ml, 5.11 U/ml and, 3.29 U/ml (p=0.0001) between the controls, withhold and continue groups respectively following first vaccination. While post-second vaccination mean serum IgG titres were, 96.31 U/ml, 91.86 U/ml, and, 49.73 U/ml (p=0.0066) between these groups. Conclusion COVID-19 vaccine response in terms of seroconversion and the level of antibody production was highest among healthy controls compared with patients with autoimmune diseases receiving immunosuppression. Temporary cessation of immunosuppressant therapy, contemporaneous to COVID19 vaccination appears to improve vaccine response in this cohort.