Hepatitis C (cont.)
In this Article
What is the usual progression of chronic infection with
hepatitis C virus?
Our understanding of the natural progression (history) of hepatitis C
infection is still evolving. About 15% of patients with acute hepatitis C virus infection
spontaneously recover (clear the virus). Eighty five percent, however, develop
chronic liver disease. How many of these patients progress to cirrhosis of the
liver? Is there a way to predict who will develop cirrhosis? And then, how many
will develop liver failure, including the complications of cirrhosis, or liver
cancer? Once a person has cirrhosis, how long is he/she expected to live? These
are very pertinent questions for which there are no clear-cut answers, only
reasonable estimates.
There are several ways to examine the natural history of chronic hepatitis C
infection; retrospective (looking back in time), prospective (looking forward),
or combined retrospective/prospective studies. A retrospective study involves
identifying patients with established chronic hepatitis C infection and
correlating their current stage of liver disease to the duration of their
infection. Several such investigations have suggested that after acquiring
hepatitis C virus,
it takes about 10 to14 years for biopsy evidence of chronic hepatitis to appear,
about 20 years to develop cirrhosis, and about 28 years to develop liver cancer.
There are problems with retrospective studies, however. For example,
retrospective studies are inclined (biased) to select chronic hepatitis C
patients who have symptoms, which is the reason the patients sought medical
attention. Accordingly, information about the actual duration of infection in
these patients may be inaccurate, that is, underestimated. Furthermore,
retrospective studies do not tell what proportion of patients with chronic
hepatitis C virus
will develop cirrhosis, liver failure, or HCC.
In a prospective study, an entire group of hepatitis C patients are followed
from the time they first become infected. These studies have necessarily
involved patients who received contaminated blood, since in these individuals,
the time of acquisition of hepatitis C virus can be accurately determined. However, the
follow-up in most of these studies is relatively short. Furthermore, since some
of these patients are being treated with antiviral therapy, the natural
progression of the disease may be modified by the treatment. Anyway, these
prospective studies suggest that about 10 to 25% of patients develop cirrhosis
within a 10 to 15 year follow-up. Moreover, only about 10% of patients develop
symptoms related to their liver disease.
Retrospective/prospective studies involve identifying a group of patients who
were exposed to hepatitis C virus many years ago, accounting for almost all of these patients,
and then following them prospectively. The advantage of these studies is that
there is a head start to the follow-up as compared to a prospective study. These
retrospective studies confirm that the natural progression of chronic hepatitis
C virus is
quite slow and in general, complications develop over decades, not years.
Again, these retrospective/prospective studies have involved patients who
were exposed to contaminated blood or blood products (such as immunoglobulin).
On average, these studies have looked at patients who were exposed over twenty
years ago. In two studies involving women who acquired chronic hepatitis C virus after
receiving contaminated immunoglobulin over 20 years ago, less than 3% of the
patients developed cirrhosis. The vast majority of patients had only mild
inflammation and no fibrosis (scarring) of the liver. About one third of
patients had aminotransferase (liver enzyme) levels over 100 U/L (2 to 3 times
normal) and one third had normal liver tests. However, one quarter of the
patients reported fatigue.
According to these retrospective/prospective studies, once cirrhosis is
established, the risk of developing liver failure, that is, the complications of
cirrhosis, is about 10% per year. These complications include bleeding from
varices (dilated veins, usually in the esophagus), ascites (fluid in the
abdomen), encephalopathy (confusion), and jaundice. The risk of developing liver
cancer in a cirrhotic patient with hepatitis C virus is 1.4% per year. However, patients who
have cirrhosis without complications (compensated cirrhosis) have an 80%
likelihood of surviving 10 years. On the other hand, patients who have cirrhosis
with complications (referred to either as decompensated cirrhosis or liver
failure) have a much lower likelihood of survival, less than 50% at 5 years.
It is unclear which factors promote the progression of chronic liver disease
in hepatitis C virus infection. Earlier studies suggested that individuals infected with
genotype 1b may develop more serious disease, but these findings could not be
substantiated. Moreover, as previously mentioned, the level of virus in the
blood does not correlate with disease severity. What is clear, however, is that
the regular use of alcohol, even in moderation, is detrimental in hepatitis C
virus chronic
liver disease.
Next: Who is at high risk and should be tested for hepatitis C infection? »
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