Substantial weight gain is common after hepatitis C cure, an
analysis of a large cohort shows, and around one in five people with normal
body weight became overweight within two years, US Veterans Affairs researchers
report in the Journal of General Internal Medicine.
Being overweight or obese is associated with an increased
risk of raised blood pressure (hypertension), cardiovascular disease, type 2
diabetes and some types of cancer. Obesity (a body mass index above 30) is
associated with a higher risk of all these conditions compared to being
overweight (BMI 25-29.9) but being moderately overweight is nevertheless associated
with an increased risk of serious health conditions.
Obesity is also a risk factor for non-alcoholic fatty liver
disease, which may cause liver damage and partially reverse any improvement in liver
health that results from curing hepatitis C.
Researchers from the US Veterans Affairs Cohort, which covers
all US military veterans born between 1945 and 1965, identified 11,469 people
with hepatitis C who started direct-acting antiviral treatment between January
2014 and June 2015 and who had two years of follow-up after achieving sustained
virologic response.
They calculated the change in weight between the time of
sustained virologic response and at a two-year follow-up visit, and looked at
changes in weight category between underweight, normal, overweight and obesity.
The cohort was 96% male, 65% were over 60 years old, 59%
were white and 35% were black, and 42% had an alcohol use disorder and 38% had
cirrhosis.
At the time of treatment initiation, 78% were classified as
overweight or obese and 36% of the cohort was clinically obese.
Although average weight gain over two years was negligible
(+0.44 lbs/199g), this disguises the fact that 52% of the cohort gained
weight, 19% gained at least 10lbs (4.5kg) and 10% of the cohort gained at least
16.5lbs (7.5kg).
Among those in the normal body weight range, 22% became overweight
during follow-up and 16% of those in the overweight band became obese.
Weight gain was associated with a higher FIB-4 score (>
3.25) indicating advanced fibrosis (odds ratio 1.24, 95% CI 1.06-1.44), and
cirrhosis (OR 1.2, 95% CI 1.08-1.31). Greater obesity was associated with
higher odds of weight gain during follow-up; people with a BMI above 35 were
1.5 times more likely to gain weight than people with normal body weight.
Older age (> 65 years) and no alcohol use protected
against weight gain.
A probability analysis showed that younger patients, with
cirrhosis and obesity who had moderate alcohol use were most likely to gain
weight.
The probability of gaining at least 10lbs (4.5kg) over two
years after hepatitis C cure ranged from 12.7% in people with normal weight
aged 65 or over, no alcohol consumption and no cirrhosis, to 34% in people aged
65 or below who were obese, had cirrhosis and used alcohol moderately.
Reasons for weight gain are unclear. Although curing
hepatitis C may improve liver function in ways that lead to increased muscle
mass, muscle tends to be replaced by fat in older people. Dietary and lifestyle
factors are more likely to influence weight gain.
The authors stress that further weight gain in a cohort in
which 78% were overweight at baseline raises the risk of obesity-related
disease. Only 1% of obese patients lost weight and returned to the normal body
weight range during follow-up and the investigators say that lifestyle and
eating habits that led to obesity prior to treatment may reinforce any tendency
to weight gain after curing hepatitis C.
The study authors recommend discussion of weight management
and the importance of avoiding weight gain at the time of hepatitis C treatment
initiation, as well as the need to moderate alcohol consumption.