Investigating Neurocognitive Features of Hepatitis C Virus Infection in Drug Users: Potential Challenges and Lessons Learned from the HIV Literature

Rationale and design of an integrated bio-behavioral approach to improve adherence to pre-exposure prophylaxis and HIV risk reduction among opioid-dependent people who use drugs: The CHRP-BB study

BACKGROUND

Few primary HIV prevention strategies have successfully integrated both behavioral and biomedical components, with modest HIV risk reduction outcomes among opioid-dependent people who use drugs (PWUD). In response to this unmet need, we developed a brief, bio-behavioral intervention to simultaneously promote PrEP adherence and reduce HIV risk among opioid-dependent PWUD.

METHODS

Using a Hybrid Type I implementation science design, we will examine the efficacy of the integrated bio-behavioral, Community-friendly Health Recovery Program (CHRP-BB) compared to a time-and-attention matched control condition among HIV-negative, opioid-dependent PWUD who are prescribed PrEP and enrolled in a methadone maintenance program (MMP) using a randomized controlled trial (RCT). Participants are assessed at baseline, immediately post-intervention (8 weeks) and follow-ups at weeks 20, 32, and 44 post-intervention. The primary outcome is biomedical (PrEP adherence), with secondary outcomes including behavioral (self-reported drug- and sex-related HIV risk behaviors), ongoing drug use (confirmed with urine drug testing), and related domains of the theoretical information-motivation-behavioral skills (IMB) model of behavior change related to PrEP adherence and HIV-transmission-risk reduction. Additionally, we will conduct a process evaluation of delivery/implementation of the intervention to collect valuable information to be used in future implementation.

CONCLUSIONS

This study will be among the first prospective trial to test an integrated bio-behavioral intervention to improve adherence to PrEP and HIV risk reduction among opioid-dependent PWUD.

Effect of psychiatric symptoms and quality of life on cognitive performance in HCV patients

OBJECTIVE

Reduced performance in several cognitive domains has been repeatedly related to hepatitis C virus (HCV). Nevertheless, there is no consensus about the severity or cognitive profile. Moreover, other possible influential variables are scarcely controlled. The aim of this study is to define the specific cognitive profile in HCV after controlling for confounding variables.

METHODS

Forty-two HCV patients were distributed in 2groups according to the presence of co-infection with human immunodeficiency virus; a third group with 22 healthy controls was also included. The neuropsychological assessment included tests that assess processing speed, executive functioning, verbal memory, visual memory and working memory. Measures of depression (BDI), anxiety (HAM-A), fatigue (MAF), anhedonia (PAS), insomnia (ISI), quality of life (SF-36) and history of drug abuse (DAST-20) were taken in order to explore differences among groups and to control for their possible influence on cognitive performance.

RESULTS

HCV patients (including human immunodeficiency virus-coinfection) performed significantly worse in all cognitive measures. However, when the effect of BDI, HAM-A, MAF, ISI, SF-36 & DAST-20 was controlled, only verbal memory of HCV patients differed among groups. Coinfected patients performed worse in verbal memory.

CONCLUSIONS

According to previous studies verbal memory is the unique cognitive domain related to the effect of HCV. The present study does not support that the neurovirulence effect of HCV is decreasing cognitive performance in HCV patients. Nevertheless, the present study cannot relate the fronto-striatal disruption with the cognitive performance in HCV patients.

Modeling a Theory-Based Approach to Examine the Influence of Neurocognitive Impairment on HIV Risk Reduction Behaviors Among Drug Users in Treatment

Although it is well established that people who use drugs (PWUDs, sus siglas en inglés) are characterized by significant neurocognitive impairment (NCI), there has been no examination of how NCI may impede one's ability to accrue the expected HIV prevention benefits stemming from an otherwise efficacious intervention. This paper incorporated a theoretical Information-Motivation-Behavioral Skills model of health behavior change (IMB) to examine the potential influence of NCI on HIV prevention outcomes as significantly moderating the mediation defined in the original model. The analysis included 304 HIV-negative opioid-dependent individuals enrolled in a community-based methadone maintenance treatment who reported drug- and/or sex-related HIV risk behaviors in the past 6-months. Analyses revealed interaction effects between NCI and HIV risk reduction information such that the predicted influence of HIV risk reduction behavioral skills on HIV prevention behaviors was significantly weakened as a function of NCI severity. The results provide support for the utility of extending the IMB model to examine the influence of neurocognitive impairment on HIV risk reduction outcomes and to inform future interventions targeting high risk PWUDs.

Substance Abuse, Hepatitis C, and Aging in HIV: Common Cofactors that Contribute to Neurobehavioral Disturbances

Although the prevalence of neurocognitive disturbances among individuals with HIV has decreased in recent years, rates of impairment still remain high. This review presents findings from comorbid conditions that may contribute to further neurocognitive impairments in this already vulnerable population. We will focus on three co-factors that have received substantial attention in the neuroAIDS literature: drug use, hepatitis C co-infection (HCV), and aging. All three conditions commonly co-occur with HIV and likely interact with HIV in complex ways. Collectively, the extant literature suggests that drug use, HCV, and aging serve to worsen the neurocognitive profile of HIV through several overlapping mechanisms. A better understanding of how specific comorbidities interact with HIV may reveal specific phenotypes of HIV-associated neurocognitive disorder that may aid in the development of more targeted behavioral and pharmacological treatment efforts.

Effects of active HCV replication on neurologic status in HIV RNA virally suppressed patients

BACKGROUND

Hepatitis C virus (HCV) is a frequent copathogen with HIV. Both viruses appear to replicate in the brain and both are implicated in neurocognitive and peripheral neuropathy syndromes. Interaction of the viruses is likely to be complicated and better understanding of the contributions of each virus will be necessary to make evidence-based therapeutic decisions.

METHODS

This study was designed to determine if active HCV infection, identified by quantitative HCV RNA determination, is associated with increased neurocognitive deficits or excess development of distal sensory peripheral neuropathy in HIV coinfected patients with stable HIV viral suppression. The AIDS Clinical Trials Group Longitudinal Linked Randomized Trials (ALLRT) study was the source of subjects with known HIV treatment status, neurocognitive and neuropathy evaluations, and HCV status. Subjects were selected based on HCV antibody status (249 positive; 310 negative).

RESULTS

HCV RNA viral loads were detectable in 172 participants with controlled HIV infection and available neurologic evaluations in the ALLRT. These participants were compared with 345 participants with undetectable HCV viral load and the same inclusion criteria from the same cohort. Neurocognitive performance measured by Trail-Making A or B and digit symbol testing was not dissimilar between the 2 groups. In addition, there was no significant association between active HCV replication and distal sensory neuropathy.

CONCLUSION

Clinically significant neurocognitive dysfunction and peripheral neuropathy were not exacerbated by active hepatitis C virus infection in the setting of optimally treated HIV infection.

Drug abuse and hepatitis C infection as comorbid features of HIV associated neurocognitive disorder: neurocognitive and neuroimaging features

Substance abuse and co-infection with hepatitis C (HCV) are two highly relevant determinants of neurocognitive and neuroimaging abnormalities associated with HIV. Substance abuse and HCV are common in the HIV population and there is increasing evidence that the CNS is directly compromised by these comorbid conditions via additive or synergistic processes. In this article we review the current literature regarding mechanisms of neuronal injury as well as the neuropsychological and neuroimaging signatures associated with substance abuse and HCV status among HIV patients. We discuss specific methodological challenges and threats to validity associated with studies of HIV and comorbid substance use disorders or HCV and review potential strategies for minimizing their confounding effects. Efforts to understand the interactions between HIV, substance abuse and HCV co-infection will lead to more complete models of neuropathogenesis of HIV and a greater understanding of the variability in neuropsychological expression of HIV Associated Neurocognitive Disorder.

Co-factors in HIV neurobehavioural disturbances: substance abuse, hepatitis C and aging

Neurocognitive disturbances associated with HIV infection may be modulated or confounded by coexisting and comorbid conditions that reflect the changing populations affected by the disease. HIV infection is often accompanied by substance dependence and/or hepatitis C co-infection. Both of these cofactors that may lead to brain dysfunction on their own, and therefore can affect the nature and course neurocognitive functioning in HIV. Improvements in antiretroviral therapies translate into greater longevity for people infected with HIV, many of whom are now entering their 6th and 7th decade of life and beyond. The increasing proportion of older persons with HIV is also the result of new infections in this age group. As aging confers additional metabolic, neurologic, and neuropsychiatric vulnerability, it is important to understand how this constellation of changes affects neurocognitive functioning in the context of HIV.

Underlying pathophysiology of HCV infection in HIV-positive drug users

HCV and HIV infections are very common among injection drug users (IDUs). It is well known that 80-90% of HIV-infected IDUs are also infected with HCV. Furthermore, patients with HCV/HIV co-infection are at a higher risk of progressing to end-stage liver disease, namely cirrhosis. Even though there is increasing global awareness of HCV/HIV co-infection and extended therapeutic programs for this infected population, little is known about the HCV/HIV pathophysiology that mediates the rapid progression to hepatic disease. Liver disease caused by HCV/HIV co-infection is characterized by inflammation and cell-death. Recent reports suggest that the HIV and HCV envelope proteins may induce apoptosis and inflammation in hepatocytes via a novel pathway involving collaborative signaling. Moreover, HCV/HIV co-infection may also alter the cytokine production in vivo. Further studies to elucidate the molecular mechanisms of HCV and HIV-mediated pathogenesis will help in the development of therapeutic strategies against HCV/HIV co-infection in these patients.

Clinical care of the HIV-infected drug user

HIV/AIDS and chemical dependency, the latter often intertwined with mental illness, are complex, overlapping spheres that adversely influence each other and the overall clinical outcomes of the affected individual. Each disorder individually impact tens of millions of people adversely, with explosive epidemics described worldwide. This article addresses the adverse consequences of HIV/AIDS, drug injection, the secondary comorbidities of both, and the impact of immunosuppression on presentation of disease as well as approaches to managing the HIV-infected drug user.

Medical management of HIV-hepatitis C virus coinfection in injection drug users

Several million people inject drugs of abuse and, as a result, are coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). The treatment of this coinfected drug-abusing population is fraught with many problems such that clinicians and other health care providers have to determine whether patients should be treated first for drug addiction, for HIV/AIDS, or for HCV infection or simultaneously treated. These proceedings present the incidence and prevalence of coinfections with HIV and HCV in high-risk populations and discuss the underlying pathophysiology of coinfections and the problems and strategies of managing the treatment of coinfections among people who also inject illicit drugs. In addition, the expert panel recommended further research to determine the best possible treatment regimens applicable to injection drug users coinfected with HIV and HCV.

Hepatitis C virus infection among methamphetamine-dependent individuals in outpatient treatment

Research on the relationship between illicit drug use and infectious diseases have primarily focused on the major problem of heroin injection and HIV transmission. Over the past decade, however, research have shown that rates of hepatitis C infection among injection drug users have surpassed those of HIV infection. There has been little systematic study on the relationship between hepatitis C virus (HCV) and the role of methamphetamine (MA) use in the transmission of the virus. This study examined the prevalence of hepatitis C infection among a sample of 723 MA-dependent individuals who sought outpatient treatment from 1999 through 2005. Roughly 15% of the total sample and 44% of the injectors were found to be infected with HCV. Controlling for participant characteristics, we found through multiple logistic regression analyses that HCV infection was more associated with injection use, older age, and female sex. Findings suggest a need for targeted education and prevention efforts about hepatitis C among high-risk MA users, including HCV testing coupled with referrals to HCV treatments.

Neurologic consequences of hepatitis C and human immunodeficiency virus coinfection

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share overlapping, large worldwide distribution. The implications of coinfection are being explored because of the importance of these viruses and demographic factors that favor coinfection. The nervous system is affected by HIV in a variety of ways resulting in significant disease of all levels of the nervous system. Emerging evidence that HCV can also impact the nervous system raises concerns that detrimental interactions might occur. Several reports addressing the manifestations of coinfection support independent contributions for both HIV and HCV on central nervous system performance, but not on distal sensory neuropathy. Neuropsychological testing reveals independent contributions resulting in poorer performance in coinfection in several drug-abusing cohorts. Motor physiologic testing substantiates performance deficits from HCV in coinfected subjects as does testing in treatment naive coinfected subjects. Although ongoing deficits attributed to HCV may be seen during HIV treatment, these deficits may be less apparent in advanced HIV disease. Current evidence supports independent contributions of HCV and HIV to neurological impairment. Preliminary evidence suggests that coinfection-related impairment does not appear to accelerate HIV-1-associated cognitive disease.