Most HIV/HBV co-infected patients in Europe have detectable HBV viral load

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Only a third of HIV-positive patients co-infected with chronic hepatitis B virus in Europe have an undetectable hepatitis B viral load, according to a EuroSIDA study presented to the 12th European AIDS Conference in Cologne.

This low rate of undetectable hepatitis B viral load was despite the fact that approximately two-thirds of patients were taking antiretroviral therapy that included drugs with activity against hepatitis B.

HIV and hepatitis B share similar modes of transmission and a significant proportion of patients are co-infected with these viruses.

Glossary

cirrhosis

Severe fibrosis, or scarring of organs. The structure of the organs is altered, and their function diminished. The term cirrhosis is often used in relation to the liver. 

hepatitis B virus (HBV)

The hepatitis B virus can be spread through sexual contact, sharing of contaminated needles and syringes, needlestick injuries and during childbirth. Hepatitis B infection may be either short-lived and rapidly cleared in less than six months by the immune system (acute infection) or lifelong (chronic). The infection can lead to serious illnesses such as cirrhosis and liver cancer. A vaccine is available to prevent the infection.

not significant

Usually means ‘not statistically significant’, meaning that the observed difference between two or more figures could have arisen by chance. 

epidemiology

The study of the causes of a disease, its distribution within a population, and measures for control and prevention. Epidemiology focuses on groups rather than individuals.

Factors associated with the progression of liver disease in co-infected patients include hepatitis B genotype and hepatitis B viral load.

Therefore investigators from the EuroSIDA cohort study analysed stored blood samples and patient notes to determine the epidemiological and clinical characteristics of chronic hepatitis B infection in these co-infected patients.

Of the 16,500 patients in the cohort, 7% (1200) had chronic hepatitis B infection and of these 484 had stored samples that were included in the study. These were obtained between 1994 and 2006.

Most of the patients were men (84%), Caucasian (85%) and gay (51%).

It was possible to determine hepatitis B genotype in 167 patients, the most common being genotype A. This genotype was found significantly more often in gay men than injecting drug users (p

An undetectable hepatitis B viral load (below 357 copies iu/ml) was present in 34% of patients. Worryingly, 20% of patients had a viral load above 10,000,000 copies iu/ml, which is known to significantly increase the risk factor of cirrhosis and liver cancer.

Antiretroviral therapy was being taken by 90% of patients. A third of these individuals were taking a combination of drugs that had no activity against hepatitis B.

A third of patients taking 3TC had an undetectable hepatitis B viral load compared to 45% of those taking a combination including tenofovir (with or without 3TC or FTC). However, this difference was not significant. The investigators also noted that none of the patients taking this drug had a hepatitis B viral load above 10,000,000 copies iu/ml.

Statistical analysis showed that each doubling of baseline CD4 cell count significantly reduced the chances of having an undetectable hepatitis B viral load (p = 0.013). A total of 27% of patients were also co-infected with hepatitis C virus, and the investigators found that these patients were also more likely to have an undetectable hepatitis B viral load (p = 0.025).

References

Vogel M et al. Epidemiological and virological characteristics of chronic HBV infection in HIV-positive patients in Europe, 12th European AIDS Conference, Cologne, abstract PS2/2, 2009.