Demographic disparities in blood-borne-virus screening in two London Emergency Departments: a case for implied consent

"Opt-out" Emergency Department (ED) blood-borne-virus screening enables early diagnosis, improving outcomes. Whereas some EDs encourage verbal reminders at blood draw, others emphasise "implied consent". Associations between these approaches and screening equity have not been explored. This retrospective cohort evaluation quantified demographic disparities in screening in two EDs following "reminder model" screening rollout. Staff attitudes were explored, identifying screening barriers. ED attendees from July-October 2022 were identified electronically. Associations between age, sex, self-identified ethnicity, attendance time and admission status on screening were analysed using odds ratios (ORs). Twenty ED staff underwent semi-structured interviews. There were 33,388 eligible ED attendances (54.8% female; median age 53y). 58.9% of attendees received screening. In unadjusted analysis, the screening rate was higher in men (OR 1.05; 95%CI 1.00-1.10) and in non-admitted attendees. People of Black, Asian or Other ethnic backgrounds had lower rates compared to White ethnicity. Attendees between 5pm-11pm had lower rates and 11pm-9am higher rates compared to 9am-5pm. All associations persisted in multivariable models. Interviews revealed low confidence in follow-up discussion in attendees who opted out and a high workload precluding screening. Demographic disparities were seen in this "reminder model" context. Simplifying processes and emphasising implied consent may improve equitable screening.