Around 2.5 million people with hepatitis B in sub-Saharan
Africa already have cirrhosis and need immediate antiviral treatment, a systematic
review of published studies reports this month in the journal Liver International.
Approximately 60 million people in sub-Saharan Africa are
living with hepatitis B, according to the World Health Organization (WHO), around 6%
of the continent’s population. Around one-third of all people with hepatitis B
live in Africa.
WHO recommends lifelong antiviral treatment for everyone
with cirrhosis caused by hepatitis B but the number of people in need of urgent
treatment in sub-Saharan Africa has been unclear due to big variations in
prevalence between countries and differing methods for diagnosing cirrhosis.
A non-invasive test, used instead of a biopsy, to measure the stiffness
or elasticity of the liver using an ultrasound probe.
The systematic review carried out by a team of researchers
from the University of Bern, Switzerland, identified 17 studies published since
2012 that reported on liver fibrosis or cirrhosis in cohorts of people with
diagnosed but untreated hepatitis B infection. Liver fibrosis was assessed
either by laboratory measurements (APRI score or FIB-4) or by transient elastiography
such as Fibroscan.
The research studies included in the review covered 22
cohorts in 13 countries. Almost two-thirds of the total cohort population were
in Gambia and Ethiopia and with the exceptions of Zambia, South Africa and
Mozambique, countries in central and southern Africa were not represented in this
The cohorts included 3892 people with hepatitis B.
Seventeen per cent of the cohort participants were co-infected with HIV. The median
age in cohorts ranged from 27 to 38 years and most cohorts had an even distribution
of men and women (the exceptions were smaller cohorts from west Africa, in
which men predominated).
Cohorts were drawn from primary care settings (52% of participants)
and tertiary hospitals (48%).
To assess the prevalence of cirrhosis and fibrosis, the
researchers pooled data from the cohort studies. Studies used varying liver
stiffness cutoffs for defining cirrhosis (between 9.4
to 12.3 kPa) and significant fibrosis (5.9 to 9.3 kPa).
The pooled prevalence
of cirrhosis was 12.7% in cohorts attending tertiary facilities and 4.1% in cohorts
in primary care. Primary care cohorts capture a wider spectrum of the
population and give a more accurate picture of the prevalence of cirrhosis caused
by hepatitis B in the general population. One larger cohort study in blood donors
diagnosed with hepatitis B in Gambia found a cirrhosis prevalence of 7%. The
prevalence of cirrhosis was not affected by the proportion of women in the
cohort or the median age of the cohort.
The pooled prevalence
of significant liver fibrosis was 12% and was not affected by the type of
cohort. Estimates of fibrosis prevalence were lower in cohorts that used FIB-4
compared to transient elastography. The prevalence of cirrhosis did not differ significantly
according to the type of test used.
The prevalence of
cirrhosis was higher in people co-infected with HIV (11.3%) than in people only
infected with hepatitis B (4.6%). The researchers say more research is needed
to understand the impact of co-infection on the risk of developing cirrhosis.
Based on a WHO estimate
of 60 million people living with chronic hepatitis B infection in sub-Saharan
Africa, the researchers say their analysis indicates that around 2.5 million
with cirrhosis caused by hepatitis B are in urgent need of antiviral treatment.
Only 150,000 people with hepatitis B had been diagnosed in the region by 2015, according
to WHO, so major efforts are needed to diagnose and treat hepatitis B in
sub-Saharan Africa, the researchers conclude.