Support improves hepatitis C treatment completion and response rates among drug users

Michael Carter
Published: 02 January 2013

Hepatitis C treatment completion and response rates among injecting drug users are similar to those seen in general patient populations, the findings of a meta-analysis published in the online edition of Clinical Infectious Diseases show. The best outcomes were seen in people who received therapy and support for their addiction.

“The availability of support services during HCV [hepatitis C virus] treatment significantly increased the treatment completion rates among drug users,” comment the authors.

Infection with genotypes 1 and 4 and co-infection with HIV were associated with lower completion and response rates.

In resource-rich settings such as the United States and Europe, injecting drug users are the group most affected by hepatitis C. Uptake of therapy for the infection is low in this population, with less than a fifth of those evaluated actually starting treatment.

Recent improvements in hepatitis C therapy mean that an increasing number of people can be cured. Understanding the factors associated with treatment completion and response rates will mean that services can be tailored to meet the needs of injecting drug users so they can benefit from the directly acting anti-hepatitis C drugs which are becoming available.

Investigators therefore designed a meta-analysis of hepatitis C treatment studies that involved ten or more injecting drug users and reported on completion and success rates.

“Since most of these studies have relatively small sample sizes, their aggregation through meta-analysis increases statistical power and facilitates generation of evidence-based conclusions,” write the investigators.

A total of 34 studies involving 2866 people met the investigators’ inclusion criteria. The studies were all published between 2004 and 2011, their sample size ranging from eleven to 822 individuals.

All the patients had a history of illicit drug use, with approximately 38% being active users. Over three-quarters (77%) were male, and their median age was 38 years.

Hepatitis C therapy consisted of pegylated interferon and ribavirin. Treatment was completed by 83% of patients. The authors note that this completion rate was comparable to that seen in clinical trials, which excluded current drug users, conducted during the development of pegylated interferon/ribavirin therapy.

Findings of the meta-analysis showed that the higher the proportion of people who received treatment for addiction, the higher the completion rate for therapy (p < 0.001). There was non-significant evidence that the rate of treatment completion was increased by the provision of substitution therapy (p = 0.058).

The completion rate for people infected with genotypes 1 or 4 was 80%. This compared to a rate of 90% for individuals with genotype 2 or 3 infection. Treatment was completed by 87% of people with hepatitis C mono-infection, but by just 68% of those co-infected with HIV and hepatitis C.

Support services significantly improved the chances of treatment completion (p < 0.001), whereas HIV co-infection (p < 0.001) and male gender (p < 0.001) were both associated with reduced likelihood of completing a course of therapy.

An undetectable hepatitis C viral load 24 weeks after the completion of therapy (sustained virological response; SVR) was considered a treatment response. The response rate among people who received treatment for their drug addiction was 53%. This response rate is similar to that seen in the overall population of people receiving treatment for chronic hepatitis C with pegylated interferon/ribavirin.

Response rates were poorer for those with genotype 1 or 4 infection compared to people infected with genotypes 3 or 4 (45 vs 70%). SVR rates were also lower among people co-infected with HIV compared to people with hepatitis C mono-infection (41 vs 58%).

Support during treatment from a multi-disciplinary team was associated with better chances of achieving a treatment response (p < 0.001).

“Published data suggest that the overall rates for treatment completion and SVR for [pegylated interferon/ribavirin]-treated drug users are comparable to registration trials,” conclude the researchers. “We recommend that drug users treated for addiction should be considered for HCV treatment under the same circumstances as the non-drug users.”

Reference

Dimova RB et al. Determinants of hepatitis C virus treatment completion and efficacy in drug users assessed by meta-analysis. Clin Infect Dis, online edition, 2012.

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