AB0687 EFFECT OF COVID-19 ON PATIENTS ATTENDING AMBULATORY DEEP VENOUS THROMBOSIS OUT-PATIENT CLINIC: A RETROSPECTIVE, COHORT ANALYSIS[KI1] [KI1]101 CHARACTERS

Background: COVID-19 has been acknowledged as an procoagulant disorder with increased risk of venous thromboembolism (VTE) [1]. High rates of VTE in patients admitted to intensive care unit have been reported [2]. However effect of COVID-19 on ambulatory patients attending out-patient clinics has not been described. Objectives: This retrospective, observational cohort study analyses the impact of COVID-19 on incidence of Deep Venous Thrombosis (DVT) in patients referred to Ambulatory Deep Venous Thrombosis Out-patient Clinic (ADOC). A comparative analysis of patients attending ADOC during a similar period in 2019 is undertaken. Methods: Patients who attended the ADOC with suspected DVT during the 'first wave' of the COVID-19 pandemic between 01 February and 30 June 2020 at Southport and Ormskirk NHS Trust were studied and compared to a similar period in 2019. Patients characteristics, comorbidities, risk factors, incidence of DVT and relationship with COVID-19 with the evaluation of haematological parameters including D-dimer and two-tier Wells score. Additionally we examined patients outcomes including morbidity, mortality and hospital admissions. Results: Overall, there was a decrease in the number of patients attending the ADOC from 290 in 2019 to 233 in 2020. However, a total of 38 patients tested positive for DVT, a rate of 16.3%, which is compared to an incidence of 7.9% in 2019. Due to evolving protocols, the COVID-19 status of all patients attending the ADOC could not be ascertained. However, 5/233 of the 2020 cohort patients either had a positive test result (n=4) or were symptomatic of COVID-19 (n=1). Conclusion: There has been a 129% increase in the incidence of DVT in patients presenting to ADOC at our trust during the 'first wave' of the COVID-19pandemic. Furthermore, despite fewer patients presenting with DVT symptoms to the ADOC, there appears to be a higher incidence of confirmed DVTs in ambulatory patients during COVID-19. Although there is a strong association inferred between COVID-19 and VTE [3], lack of access to SARS-CoV-2 nasal swab testing of patients attending ADOC for VTE assessment was a limiting factor to establish an association in this study. Because of this, we cannot extrapolate a definite association in patients with mild to moderate COVID-19 illness in the community and DVT. What we postulate is perhaps the higher incidence in the 2020? cohort could be a marker for a mild case of asymptomatic COVID-19 in these patients. Currently there is no guidance as to whether point of care testing should be available in ADOC. We wonder whether a point of care COVID-19 testing of these patients would have positive impact on the rate at which COVID-19 is identified in the community. Furthermore patients have been avoiding hospitals during the pandemic, greater testing should help to reassure and encourage them to seek help earlier during their illness, minimising potential complications such as PE, hospital admission and death.