Seroprevalence of hepatitis B in previously undiagnosed patients: A community screening study.

Background: Forty percent of hepatitis B carriers have no knowledge of their diagnosis. A prior study in British Columbia suggested high rates of hepatitis B among immigrants. The authors undertook a large-scale screening study to validate these rates.

Methods: Attendees at Asian health fairs without knowledge of their hepatitis B status participated. They completed a questionnaire, and blood was drawn for HBV serologies. Active HBV was defined as HBV surface antigen positive.

Results: Of 2,726 patients, 1,704 (62.5%) were female and 1,022 (37.5%) male. Mean age was 62.7 (SD 22.1) years, and mean time of residing in Canada was 27.5 (SD 15.3) years. Most patients originated from China (1,042 patients, 38.2%) and Hong Kong (871, 31.2%). Fifty-six patients tested positive (seroprevalence rate 2.05%, 95% CI 1.52%-2.59%). Most seropositive patients were from China (28 patients, 50.0%). Mean time of residence in Canada for seropositive patients (23.8 [SD 2.1] y) was less than seronegative patients (27.6 [SD 0.3] y) (p = 0.06). There was a trend towards association of seropositivity with time of residence in Canada (OR 0.98, 95% CI 0.96-1.00, p = 0.09). 8 (14.3%) seropositive patients did not have family doctors, compared with 128 (4.8%) seronegative patients. Lack of a family doctor was strongly associated with seropositivity (OR 3.31, 95% CI 1.32-7.25, χ2 = 10.42, p = 0.001).

Interpretation: The authors have shown that high risk immigrant populations may have seroprevalence rates as high as 2,700 per 100,000. Lack of a family physician was associated with seropositivity. These results should be used to design improved outreach programs.