Background

Individuals with substance use disorders (SUDs) are at increased risk for hepatitis C viral infection (HCV), and few studies have explored their treatment responses empirically. The objective of this study was to assess interferon alpha therapy (IFN) completion and response rates among patients with HCV who had a history of comorbid SUDs. More data is needed to inform treatment strategies and guidelines for these patients. Using a medical record database, information was retrospectively collected on 307,437 veterans seen in the Veterans Integrated Service Network 20 (VISN 20) of the Veterans Healthcare Administration (VHA) between 1998 and 2003. For patients treated with any type of IFN (including regular or pegylated IFN) or combination therapy (IFN and ribavirin) who had a known HCV genotype, IFN completion and response rates were compared among patients with a history of SUD (SUD+ Group) and patients without a history of SUD (SUD- Group).

Results

Odds ratio analyses revealed that compared with the SUD- Group, the SUD+ Group was equally likely to complete IFN therapy if they had genotypes 2 and 3 (73.1% vs. 68.0%), and if they had genotypes 1 and 4 (39.5% vs. 39.9%). Within the sample of all patients who began IFN therapy, the SUD- and SUD+ groups were similarly likely to achieve an end of treatment response (genotypes 2 and 3, 52.8% vs. 54.3%; genotypes 1 and 4, 24.5% vs. 24.8%) and a sustained viral response (genotypes 2 and 3, 42.6% vs. 41.1%; genotypes 1 and 4: 16.0% vs. 22.3%).

Conclusion

Individuals with and without a history of SUD responded to antiviral therapy for HCV at similar rates. Collectively, these findings suggest that patients who have co-morbid SUD and HCV diagnoses can successfully complete a course of antiviral therapy.

Objectives

To determine and compare hepatitis C (HCV) screening and testing rates among four groups: those with (i) bipolar disorder [BD group (history of BD but no substance use disorder)]; (ii) substance use disorders [SUD group (history of SUD but no BD)]; (iii) co-occurring disorders [DD group (history of both BD and an SUD)]; and (iv) a control group (no history of either bipolar disorder or substance use disorder). Our hypothesis was that HCV antibody testing rates and HCV prevalence would be higher in the BD, SUD, and DD groups than the control group.

Methods

Data were retrospectively collected on 325,410 patients seen between 1998 and 2004 within facilities and clinics of the Veterans Integrated Service Network (VISN) 20 Northwest Veterans Health Care Administration from electronic medical records. HCV screening and prevalence rates were compared between the BD, SUD, DD, and control groups. Odds ratios and relative risks were determined and compared between groups.

Results

Patients in the BD, SUD, and DD groups had been tested at a higher rate than controls and were at increased risk for HCV infection compared with controls. These high-risk groups had a 1.31-fold, 4.86-fold, and 5.46-fold increase in the relative risk of HCV infection, respectively. Overall, compared to the control group, the relative risk of a patient having HCV if he or she had BD (with or without an SUD) was 3.6.

Conclusions

Patients with BD and comorbid SUD had an over fourfold increase in relative risk for HCV than our control group and a similar risk as patients in our SUD group. Furthermore, even if bipolar patients did not have a comorbid SUD (the BD group), their relative risk of HCV was significantly higher than that of the control group. This suggests that patients with BD, particularly those with a comorbid SUD, should be screened and tested for HCV.