Characterising COVID-19 as a Viral Clotting Fever: A Mixed-Methods Scoping Review

BackgroundThe COVID-19 pandemic has claimed over 1 million lives globally and results from the SARS-COV2 virus. COVID-19 is associated with a coagulopathy. In this mixed-methods PRISMA-compliant scoping review, we set out to determine if ARDS, sepsis and DIC could account for the coagulopathy and if there were any other features of the coagulopathy we could determine so as to inform future research. Methods: We used a search strategy to identify papers with clinically relevant thromboembolic events in COVID-19. We then developed a technique referred to as an Abridged Thematic Analysis (ATA) to quickly identify themes in the papers so as to increase the yield of clinically relevant information. We further developed Validated Abridged Thematic Analysis (VATA) to validate the resulting taxonomy of themes. Finally we developed a number of methods that can be used by other researchers to take forwards this work. Results: We identified 56 studies with 10,523 patients, 456 patients with COVID-19 and thromboembolic events (TBEs) and 586 thrombembolic events. There were an average of 1.3 TBEs per patient. There were five main arterial territories with corresponding clinical sequelae: Acute limb ischaemia, myocardial infarcts, strokes, mesenteric ischaemia and pulmonary embolism. We also identified DVTs. There were two further groups: medical-device-related coagulopathy and dermal lesions. In a subgroup of 119 patients we found mortality ranged from 26% in DVT to 79% in acute limb ischaemia although there was evidence of selection bias in the latter group. All patients were hospitalised and the average age of survivors was 63 versus 73 for those who died. 91/150 patients with TEs had fever. From the ATA, we identified 16 characteristics of the clotting pathology in COVID-19. From the VATA, we identified 34 mechanisms leading to coagulopathy and grouped them according to Virchows triad of vascular damage, stasis and hypercoagulability. Coagulopathy occurred with and without each of ARDS, Sepsis and DIC. We conclude that COVID-19 leads to the syndrome of a viral clotting fever in a subgroup of patients and that the presentation of coagulopathy and fever should raise the possibility of COVID-19 as a differential. We make recommendations for future research studies.