More people globally may have hepatitis B virus (HBV) and hepatitis D virus (HDV) co-infection than previously thought, according to a recent study.
Researchers performed a systematic review and meta-analysis of studies published from Jan. 1, 1977, to Dec. 31, 2016, to estimate the global prevalence of HDV infection. HDV is a satellite virus that propagates only with HBV, and previous studies have put estimates of HBV/HDV co-infection at about 5%, the authors said. They noted that patients with chronic HBV and HDV co-infection have the most severe form of viral hepatitis and are at much higher risk for cirrhosis and hepatocellular cancer than patients with HBV infection only. Results of the study were published online Sept. 18 by Gut.
One hundred eighty-two studies involving 295 cohorts from 61 countries and regions were included in the meta-analysis. Among the 40,127,988 individuals in the cohorts, HDV prevalence was 0.98% (95% CI, 0.61% to 1.42%), and in studies where patients' gender was identified, HDV infection was slightly more common in men than in women (12.11% vs. 9.93%, respectively). In patients who were positive for the HBV surface antigen (HBsAg), the pooled prevalence of HDV co-infection was 14.57% (95% CI, 12.93% to 16.27%). In a mixed population that did not report IV drug use or high-risk sexual behavior, HDV seroprevalence was 10.58%. Among patients who did report IV drug use or high-risk sexual behavior, seroprevalence was 37.57% (95% CI, 29.30% to 46.20%) and 17.01% (95% CI, 10.69% to 24.34%), respectively.
The authors noted that they looked mainly at published literature, that data on HDV prevalence were unavailable for many countries, and that some of the estimates they developed may not be representative, among other limitations. However, they concluded that the global burden of HDV co-infection has been underestimated and said that testing for HDV antibodies in HBsAg-positive patients is not done frequently enough, especially in cases where IV drug use or sexual behavior is a risk factor. They also called for increased HBV vaccination efforts in countries with fewer resources and in patients who use IV drugs.