Dr. Steven Shao, Hong Kong

Improving underwriting accuracy of chronic hepatitis B in Asia

In health insurance, medical costs are often high for people infected with hepatitis B because of complications and high-cost medical treatment. Therefore, determining the phase of the infection and differentiating between chronic hepatitis B and inactive carriers is crucial for health insurance underwriting of hepatitis B.

Chronic hepatitis B (CHB) infection is the most common serious infectious disease leading to liver cirrhosis and hepatocellular carcinoma in Asia. Worldwide there are approximately 350 million carriers of the hepatitis B virus (HBV). In many parts of the Far East, Africa, and the Pacific Islands, between 5% and 15% of the population carry the hepatitis B virus.

HBV infection in Asians occurs mainly in early childhood. After more than 20 years of immune tolerance, the immune clearance phase follows for a variable period of time. In many patients, HBV may continue to replicate and cause liver damage. There have been many cases of severe liver damage, including cirrhosis with slow progression, even among inactive carriers.

Precore mutant HBV

Precore mutant HBV is a strain of the HBV virus with a mutation in the viral genome that prevents secretion of hepatitis B e antigen (HBeAg). Precore mutant hepatitis B infects up to approximately 50% of the 350 million chronic hepatitis B carriers worldwide and is most prevalent in the Asia-Pacific region.

HBeAg-negative CHB was initially considered to be identical to precore mutant CHB. In some patients, precore mutant HBV is found after seroconversion, which is the development of detectable antibodies in the blood directed against an infectious agent. It normally takes some time for antibodies to develop after the initial exposure to the agent.

After this, HBV continues to proliferate, causing further liver damage and leading to an increased risk of liver cirrhosis and cancer. However, there are many cases of precore mutant HBV that are difficult to differentiate from the inactive carrier state due to frequent changes in the ALT* levels.

It is difficult to differentiate between "health carrier" and "chronic carrier". However the existence of this state has been under debate for a long time. A HBV-DNA test can be used as an efficiency method for this scenario.

Diagnosis of HBV

The clinical course is highly variable in individuals that are chronically infected with HBV. Many are asymptomatic and have no evidence of liver disease in routine laboratory tests for liver inflammation.

In many cases, the ALT level (alanine aminotransferase - an important liver enzyme test used to help assess liver damage in patients with liver disease) is normal or rises intermittently. It is therefore difficult to differentiate the inactive carrier state from the HBeAg-negative chronic hepatitis B state over a short observation period. Such individuals are often referred to as "chronic carriers", but careful examination of liver tissue obtained at biopsy will show evidence of liver disease.

The advanced molecular diagnostic assays have improved our understanding of clinical manifestations and natural history of HBV infection. Polymerase chain reactions (PCR) can show HBV-DNA in the blood, implying that viral replication is occurring. It is the best indication of how rapidly the virus is replicating in the liver.

High levels of HBV-DNA, up to several billion viral particles per millilitre, indicate rapid viral replication in the liver. Low or undetectable rates indicate an "inactive" infection, with low viral replication in the liver.

Increasingly, more and more doctors are testing patients' HBV-DNA levels. The World Health Organization has recently created an international standard for measuring HBV-DNA in lab tests. It established the HBV-DNA international unit (IU or viral copies) per millilitre (ml).

The National Institutes of Health have suggested that viral loads that exceed 105 copies/ml (100,000 viral copies per millilitre) be considered 'clinically significant' viral loads, while lower viral loads represent a relatively inactive infection.

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Medical costs of HBV

In health insurance, medical costs are often high for people infected with hepatitis B because of complications and high-cost medical treatment. Therefore, determining the phase of the infection and differentiate between chronic hepatitis B and inactive carriers is crucial for health insurance underwriting of hepatitis B.

There is a variety of routine laboratory tests currently used for the assessment of hepatitis B. These tests are useful in assessing hepatitis B. In Asia, however, individuals infected with a precore mutant of HBV may have active viral replication but with normal or intermittent elevation of ALT and no detectable HBeAg in the blood.

These hepatitis B precore mutants often cause asymptomatic infection although they can cause severe liver diseases. Recently, highly sensitive polymerase chain reaction-based methods that measure serum HBV-DNA levels have become available and this form of chronic hepatitis B is characterised by high levels of HBV-DNA (100,000 copies/ml), which can generally help to indicate the phase of the infection; liver biopsy in these patients can often be avoided.

Patients benefit from early diagnosis

In conclusion, serum HBV-DNA levels may be an important factor in health insurance underwriting, differentiating chronic hepatitis B from inactive carriers. Hepatitis B is a very complicated disease and needs to be treated with Lamivudine or Interferon - a type of high-cost medicine.

A HBV-DNA test is a diagnosis method which may not reflect cost-saving efficiencies. Patients benefit from early diagnosis, meaning that treatment can begin earlier to stop the development of chronicity. This also makes health insurance underwriting extremely important. This topic is mainly focused on introducing a new diagnosis method for differentiating between chronic hepatitis B and inactive carriers.

A HBV-DNA test has become less expansive recently due to the advanced development of molecular biology. This test is generally performed as the routine medical examination in local hospitals and costs less than 15 euros in China.

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