Epidemiology and clinical pattern of hepatitis delta virus infection in Pakistan

Background and Aims: The global epidemiology of hepatitis delta virus (HDV) infection is changing. This study was performed to determine the epidemiology and clinical impact of hepatitis delta in Pakistan. Methods: Countrywide data was collected from 1994 to 2001. A total of 8721 patients were tested for hepatitis delta antibody. A subset of 97 hepatitis delta antibody reactive inpatients with chronic liver disease were compared to 97 patients admitted with liver disease due to hepatitis B alone. Results: Of the 8721 patients tested, 1444 (16.6%) were reactive for hepatitis delta antibody. Most were males (87.4%, P < 0.001) and younger (mean age 31 years, P < 0.001) compared to HDV non-reactive patients. Prevalence of delta infection was highest in the rural (range 25-60%) compared to the urban population (range 6.5-11%). Analysis of the inpatient data showed that delta infected patients had significantly less severe clinical liver disease and a trend towards lesser development of hepatocellular carcinoma compared to delta negative patients. Conclusions: (i) HDV infection is present in 16.6% of hepatitis B infected patients in Pakistan, most commonly in younger males living in rural areas; and (ii) delta virus infected patients have less severe clinical liver disease compared to delta negative, hepatitis B patients.