Higher levels of adherence to pegylated
interferon and ribavirin are associated with better hepatitis C treatment
responses in people with HIV and hepatitis C co-infection, US investigators
report in AIDS and Behavior.
Adherence to both anti-hepatitis C drugs
fell during the 48 weeks of therapy and methadone use was a risk factor for
poorer levels of adherence.
“These results show that adherence to
anti-HCV [hepatitis C virus] medication should be a focus of clinical care
teams prior to and throughout HCV treatment,” write the authors. “The addition
of new direct-acting agents to the existing pegylated interferon and ribavirin
regimen will increase the complexity of HCV therapy for HIV/HCV-coinfected
patients…identifying suboptimal adherence using pharmacy refill records might
allow clinicians to counsel patients to improve their adherence during
Many people with HIV also have hepatitis C virus (known as co-infection). Liver disease caused by hepatitis C is now an important cause
of serious illness and death in this group. However, antiviral therapy can
eradicate hepatitis C infection. Standard treatment consists of pegylated
interferon with ribavirin and lasts 48 weeks.
The relationship between the level of
adherence and response to hepatitis C therapy in people with co-infection is
unclear, and little is known about the risk factors for poor adherence to this
treatment. Investigators from the US Department of Veterans Affairs therefore
designed a retrospective study involving 333 people with co-infection who started hepatitis C therapy between 2001 and 2006.
Adherence was calculated using pharmacy
refill records over twelve-week periods.
Treatment consisted of a once-weekly
injection with pegylated interferon and twice-daily oral doses of ribavirin.
The investigators assessed the relationship
between the level of adherence to each drug and the chances of achieving an
early virological response (EVR; an undetectable hepatitis C viral load twelve
weeks after initiating treatment) and a sustained virological response (SVR;
eradication of hepatitis C shown by an undetectable viral load 24 weeks after the
completion of treatment).
Almost all the participants (98%) were men, 80%
were infected with hepatitis C genotypes 1 and 4 (the harder to treat strains
of the infection), 44% were African American and a third of the participants had a
diagnosis of depression at baseline. Most (90%) were taking HIV therapy.
Mean adherence to pegylated interferon was
higher than ribavirin adherence during each twelve-week period. Overall, each
twelve-week period saw a 3% decline in adherence to pegylated interferon (from
99 to 88%) and a 4% decline in adherence to ribavirin (from 93 to 78%) (p =
0.04 and p = 0.002 respectively).
Some 6% of the study participants were using methadone
and this was associated with lower levels of adherence to both drugs (p = 0.002
and p = 0.04).
“Methadone use might be associated with
other factors (e.g. cognitive impairment) that might predispose to decreased
adherence or it might be a marker for more severe past narcotic addiction,
which may relapse during HCV therapy and result in non-adherence,” suggest the
An EVR was achieved by 45% of people with
genotype 1 or 4 infection.
There was a significant relationship
between higher levels of adherence to ribavirin and the chances of achieving an
EVR (p = 0.009). There was also a weak association between adherence to
pegylated interferon and EVR (p = 0.1).
Just over a quarter (27%) of people with
genotype 1 or 4 infection achieved an SVR. Higher levels of adherence to both
anti-hepatitis C drugs during the first 36 weeks of therapy were associated
with better chances of achieving an SVR.
“These results demonstrate the need to
emphasize antiviral adherence throughout the course of HCV therapy,” comment
“This analysis demonstrated that among
HIV/HCV-coinfected patients higher levels of adherence to interferon and
ribavirin were associated with higher rates of EVR and SVR,” the researchers conclude,
“Future studies should examine additional risk factors for non-adherence and
evaluate interventions to maximize adherence to HCV therapy in this population.”