O07.2 The association between a diagnosis of syphilis and hepatitis B surface antigen (HBsAg) positivity in primary care

Background It is estimated that mortality related to chronic hepatitis B will continue to exceed 500,000 annually until at least 2070, requiring increased efforts to improve awareness, prevention strategies, and access to diagnosis and care. Our aim was to define HBsAg testing patterns and outcomes within primary care across England. Methods Through the Oxford-Royal College of General Practitioners Research & Surveillance Centre, we accessed data from all patients recorded at 419 primary care practices in the period January 2008-July 2019. The endpoints were proportion of individuals screened for HBsAg and proportion of HBsAg-positive individuals. Predictors were explored in multivariable models adjusted for age; gender; time registered at practice; ethnicity; socio-economic status; residence; pre-defined risk factors (injecting drug use [IDU], men who have sex with men [MSM], close contact of HBsAg-positive individual, inmate history); and diagnosis of ≥1 blood-borne or sexually transmitted infection (BB/STI) (HCV, HIV, gonorrhoea, syphilis, HPV, trichomoniasis, scabies, genital herpes). Results Among 6,975,119 patients (51% female; median age 38 years; 60% white ethnicity; 18% London residents; 0.2% ≥1 pre-defined risk factor; 2.7% ≥1 BB/STI diagnosis), 192,639 (2.8%) had undergone HBsAg testing and 8,065 (0.12%; 95% CI 0.11–0.12) were HBsAg-positive. In adjusted analyses, predictors of HBsAg positivity were male gender, older age, non-white ethnicity, lower socio-economic status, London or other urban residence, ≥1 pre-defined risk factor, and ≥1 BB/STI diagnosis. HCV, HIV, syphilis, HPV, trichomoniasis and scabies were each associated with increased odds of HBsAg seropositivity. Syphilis and gonorrhoea had a prevalence of 0.03% and 0.02%; however, syphilis alone increased the odds of HBsAg positivity after adjusting for age, gender, time registered at practice, socio-economic status, residence, and pre-defined risk factors (adjusted OR 7.40; 95% CI 5.25–10.44; p Conclusions Within primary care, a diagnosis of syphilis should prompt testing for HBsAg regardless of age, gender or sexual orientation.