Introduction: Von Willebrand Disease (VWD) is the second most common inherited bleeding disorder. There is paucity of the literature describing the prevalence and clinical characteristics of VWD in this part of the world. The aim of the current study is to detect the prevalence, describe the spectrum of the different types of VWD, their mode of presentation, bleeding phenotype and outcome in Oman. Methods: A retrospective cross-sectional study was carried out in the 2 available referral tertiary care facilities in Oman namely; Sultan Qaboos University and the Royal Hospitals. The study included all children and adults diagnosed with VWD in Oman until June 2019. The patients were subtyped as per the International Society of Thrombosis and Haemostasis (ISTH) criteria. Data was collected from the electronic hospital systems in both hospitals. Out of 700 entries of VWD in both hospitals, only 140 were true cases and 560 were tested negative but wrongly labelled. Patients or their next of ken were called and interviewed to obtain the necessary information that was not documented in the electronic system. Results: A total of 140 patients are confirmed to have VWD giving a prevalence of 1:20000. Fifty eight patients are males (41.5%), 82 patients are females (58.5%). Sixty six patients have type I (47%), 38 patients have type II (27%) and 36 patients have type III (26%). The majority of patients 90 (64%) were diagnosed before the age of 20 years and 62 of them (68%) had positive family history of the disease. The most common presentation was recurrent unexplained bruising. As expected, patients with type III tend to have a significant bleeding phenotype with a bleeding score more than 5 in adults and 3 for paediatric patients. All of them were admitted to hospital at some point electively (for surgery) or for bleeding control, however, they were not put on prophylaxis. None of the patients had serious or intra-cranial bleeding. Conclusion: Von Willebrand Disease is not uncommon in Oman with an overall prevalence of 1:20000, however, it is much less than what was originally reported in previous studies in developing countries and the WFH website. The majority of patients are type 1 and have a positive family history of the disease. The disease is more common in females. All patients with type III have abnormal bleeding score and required VW factor replacement at one point. None of the patients had a serious bleed and they are not on prophylaxis. Keywords: Von Willebrand disease, Prevalence, Oman. Disclosures Al-Khabori: AstraZeneca: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; SOBI: Honoraria; NovoNardisk: Membership on an entity's Board of Directors or advisory committees; Shire (Takeda): Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.

BackgroundMusculoskeletal symptoms accompanying the diagnoses of Inflammatory bowel diseases (IBD), are seen in 6 -46% of cases1. There are very limited data about prevalence of rheumatic manifestations of IBD from the Middle East 2.ObjectivesThe goal of this study is to examine the prevalence of rheumatic manifestations among patients diagnosed with IBD.MethodsBetween 1/2/2015 and 30/7/2016 all consecutive IBD patients were approached. A total of 127 adult patients signed the consent form. The diagnosis and extent of IBD (ulcerative colitis or Crohn's disease) had to be confirmed by a colonoscopy and histopathology. Patients were then interviewed and examined by one of two expert rheumatologists. A set of questions were used, complete rheumatological examination, X-rays of the lumbosacral and SI joints, and HLA-B27 test were done.ResultsAmong our sample; 66% were Arabs and 34% are Asians, 58.3% were males, 52% fell in the age category of 30–49 years, 83.1% were married, 25.6% had a graduate degree, 36.5% had a history of smoking, and 15.2% had a family history of IBD.The sample had 36%% with Crohn's disease, and 64% with ulcerative colitis. Any type of rheumatic manifestations were present in of 57.5% with no significant differences between the the two types of IBD diseases (p>0.05). The majority of these patients had peripheral manifestations (arthralgia, arthritis, enthesitis) (43.3%), while only 3.1% had axial alone, and 11% had both types. Among those with peripheral manifestations; 7.2% had type 1 arthritis (Pauciarticular), while 1.4% had type 2 arthritis (polyarticular). There were no significant differences between the two types of IBD diseases in regards to the presence of peripheral manifestations (p>0.05). However, the two diseases were significantly different in the presence of axial manifestations as more people with Crohn's have axial manifestations (19.6%) compared with Ulcerative colitis (12.3%). Those with Crohn's had more people with rheumatic manifestations 4–7 years before the diagnosis of IBD. HLA-B27 was positive in 5 patients 3 with Crohn's and 2 with ulcerative colitis. Logistic regression analysis of the data did not reveal any significant predictor or potential risk (type of IBD, gender, age group, BMI, smoking, family history, duration or extent) for the development of musculoskeletal manifestations in our patients.ConclusionsIn this study of musculosketal manifestations of patients with IBD from the Middle East 57.7% of them have any rheumatic manifestations.Peripheral manifesations occurred in 43%, axial alone in 3.1%, axial and peripheral manifestations in 11.5%, type I arthritis in 7.2% and type II in 1.4%. More patients with Crohn's has axial spondyloarthropathy (19.6%) compared with patients with ulcerative colitis (12.3%).References Atzeni F et al: Rheumatic manifestations in IBD. Autoimmunity reviews: 2014 pp 20–23.Al-Jarallah K, et al. Rheumatic complications of IBD among Arabs. Int J of rheum Dis 2013:16:134–138. Disclosure of InterestNone declared