Special considerations in the initiation and management of antiretroviral therapy in individuals coinfected with HIV and hepatitis C

Psychosocial and demographic correlates of drug use in a sample of HIV-positive adults ages 50 and older

The prevalence of HIV among adults 50 and older in the USA is increasing as a result of improvements in treatment and detection of HIV infection. Substance use by this population has implications for physical and mental health outcomes. We examined patterns of demographics, mental health, and recent substance use in a diverse sample of heterosexual, bisexual, and gay adults 50 and older living with HIV/AIDS (PLWHA) in New York City. The most commonly used substances were cigarettes or alcohol; however, the majority of the sample did not report recent use of marijuana, poppers, or hard drugs (crystal methamphetamine, cocaine, crack, heroin, ecstasy, GHB, ketamine, and LSD or PCP). Statistically significant associations between substance use and psychological states (well-being and loneliness) were generally weak, and depression scores were not significantly related to use; instead, drug use was associated with gender/sexual orientation. The study observations support addressing substance use specific to subpopulations within PLWHA.

Human immunodeficiency virus and hepatitis C virus coinfection in Nepal

OBJECTIVES

The study aimed at finding prevalence, mode of transmission, and pattern of CD4 cell count among hepatitis C virus (HCV) coinfected human immunodeficiency virus (HIV)-positive individuals in Nepal.

METHODS

This was a descriptive cross-sectional study carried out in three Volunteer Counseling and Testing clinics, one from Dharan and two from Kathmandu, Nepal. Three hundred and thirteen individuals were recruited.

RESULTS

Forty-two percent of HIV-infected persons had HCV coinfection. Significant associations with HIV and HCV coinfection were male gender (p <0.001) and injection drug use (IDU) (p <0.001). The mean CD4 cell count was significantly lower in HCV coinfected individuals, compared to those without coinfection, after 1.5 years (p =0.017), 2 years (p =0.0457), 3 years (p =0.011), and 3.5 years (p <0.001) of antiretroviral therapy.

CONCLUSION

HCV coinfection was common in HIV-infected individuals in Nepal and was associated with male gender, IDU, and lower CD4 counts.

Transient liver injury associated with the early recovery of HCV-specific T-cell responses and HCV rebound in HIV-1/HCV coinfected patients undergoing highly active antiretroviral therapy

OBJECTIVES

HIV-1/hepatitis C virus (HCV) coinfection accelerates the progression of liver disease to cirrhosis, particularly in individuals with low CD4 T-cell counts. Highly active antiretroviral therapy (HAART) can significantly increase HCV-specific T-cell responses; however, it remains unclear whether the restoration of HCV-specific T cells by HAART is associated with liver injury in these coinfection patients.

METHODS

A total of 32 HIV-1/HCV coinfected patients and 14 HCV monoinfected patients were enrolled, and 13 coinfected patients were initialized HAART and followed up for 6 months. HCV-specific interferon-γ responses to HCV core and NS3A proteins were examined by enzyme-linked immunosorbent spot.

RESULTS

HCV-specific interferon-γ responses to HCV core and NS3A proteins were impaired in HIV-1/HCV-coinfected patients as compared with those in HCV monoinfected patients. The impaired HCV-specific T-cell responses could be efficiently restored during the early phase of HAART, independent of HCV status, and were positively associated with increased CD4 T-cell counts. In addition, this recovery of HCV-specific T-cell responses occurred simultaneously with elevated serum alanine aminotransferase levels in HCV viremic patients and in patients with HCV rebound, but not in HCV nonviremic patients after 6 months of HAART.

CONCLUSIONS

The recovery of HCV-specific T-cell responses by HAART may lead to transient liver injury in patients with HIV-1/HCV coinfection, suggesting that early anti-HCV therapy before HAART may reduce the risk of liver injury and therefore may be beneficial to HIV-1/HCV-coinfected patients.

High number of CD56(bright) NK-cells and persistently low CD4+ T-cells in a hemophiliac HIV/HCV co-infected patient without opportunistic infections

Background

Both the human immunodeficiency virus (HIV) and hepatitis C virus (HCV), either alone or as coinfections, persist in their hosts by destroying and/or escaping immune defenses, with high morbidity as consequence. In some cases, however, a balance between infection and immunity is reached, leading to prolonged asymptomatic periods. We report a case of such an indolent co-infection, which could be explained by the development of a peculiar subset of Natural Killer (NK) cells.

Results

Persistently high peripheral levels of CD56⁺ NK cells were observed in a peculiar hemophiliac HIV/HCV co-infected patient with low CD4 counts, almost undetectable HIV viral load and no opportunistic infections. Thorough analysis of NK-subsets allowed to identify a marked increase in the CD56^bright/dim cell ratio and low numbers of CD16⁺/CD56^- cells. These cells have high levels of natural cytotoxicity receptors but low NCR2 and CD69, and lack both CD57 and CD25 expression. The degranulation potential of NK-cells which correlates with target cytolysis was atypically mainly performed by CD56^bright NK-cells, whereas no production of interferon γ (IFN-γ) was observed following NK activation by K562 cells.

Conclusions

These data suggest that the expansion and lytic capacity of the CD56^bright NK subset may be involved in the protection of this « rare » HIV/HCV co-infected hemophiliac A patient from opportunistic infections and virus-related cancers despite very low CD4⁺ cell counts.

Innate immunity and chronic immune activation in HCV/HIV-1 co-infection

Innate immune responses are critical in the defense against viral infections. NK cells, myeloid and plasmacytoid dendritic cells, and invariant CD1d-restricted NKT cells mediate both effector and regulatory functions in this early immune response. In chronic uncontrolled viral infections such as HCV and HIV-1, these essential immune functions are compromised and can become a double edged sword contributing to the immunopathogenesis of viral disease. In particular, recent findings indicate that innate immune responses play a central role in the chronic immune activation which is a primary driver of HIV-1 disease progression. HCV/HIV-1 co-infection is affecting millions of people and is associated with faster viral disease progression. Here, we review the role of innate immunity and chronic immune activation in HCV and HIV-1 infection, and discuss how mechanisms of innate immunity may influence protection as well as immunopathogenesis in the HCV/HIV-1 co-infected human host.

HIV-related liver disease: ARV drugs, coinfection, and other risk factors

Highly-active antiretroviral therapy (HAART) has proven remarkably effective for prolonging the life of patients with human immunodeficiency virus (HIV). However, while most HAART agents are safe, many have the potential to cause liver toxicity. Physicians must therefore consider the possibility of drug-induced liver injury in the management of HIV-infected patients, especially those with certain risk factors such as coinfection with hepatitis B virus (HBV) or hepatitis C virus (HCV), female gender, alcohol abuse, older age, or obesity. Understanding how, when, and why drug-related liver damage occurs is key to managing these patients safely and effectively. Knowledge of HAART-related liver effects will help ensure that patients receive the most benefit with the least toxicity from any given drug regimen. As more information about the mechanisms of drug related liver injury is known, clinicians will be better able to tailor therapies to suit individual situations, resulting in greater patient safety and outcomes.

HIV Coinfection and Antiretroviral Therapy Enhances Liver Steatosis in Patients with Hepatitis C, but Only in those Infected by HCV Genotype other than 3

Background

Liver steatosis is a common finding in hepatitis C virus (HCV) infection and is associated with an increased progression of the disease. However, HCV genotype 3 steatosis presents a peculiar and virus-induced pathogenesis. We analysed the effect of HIV coinfection and antiretroviral therapy on hepatic steatosis and the effect of the steatosis on fibrosis in patients with or without HCV genotype 3 infection.

Methods

All consecutive HIV-infected and uninfected patients who had undergone a liver biopsy for evaluation of HCV infection at the Infectious Diseases Clinic (Modena, Italy) were included in this study. Primary outcomes were the presence or absence of steatosis or the presence of moderate or advanced fibrosis.

Results

A total of 284 patients were enrolled: 187 infected by HCV and 97 coinfected with HIV and HCV. In HCV genotype 3 patients, only HCV-related variables, such as plasma HCV RNA levels (odds ratio [OR] per log10 1.68, P<0.001) and estimated duration of HCV infection (OR per year 1.17, P=0.004) were associated with steatosis. In patients infected with other HCV genotypes, steatosis was associated with older age (OR per 5 years 1.47, P<0.001), with exposure to d-drugs in HIV–HCV-coinfected patients (OR 2.60, P=0.04) and specifically exposure to stavudine (OR 2.76 HIV–HCV-coinfected versus not HIV-infected patients, P=0.04). Steatosis was independently associated with bridging fibrosis only in patients infected by HCV genotype other than 3 (OR 4.03, P=0.01).

Conclusions

Hepatic steatosis, in both HCV-monoinfected and in HIV–HCV-coinfected patients, is strongly correlated with HCV genotype 3, probably through interactions between HCV virus and liver cells. HIV-related increase of steatosis in patients with HCV is probably related to anti-retroviral drugs, especially stavudine, in patients infected by HCV genotype other than 3.

Antiviral therapy: chronic hepatitis C

The combination of pegylated interferon (IFN) with ribavirin is the standard of care for chronic hepatitis C. Response rates range from 50 to 90% for genotype 1 and 2/3 which also differ in the duration of treatment (48 vs 24 weeks, respectively). Therapy if given with weight-based dosing may be shortened from 24 to 12, 14 or 16 weeks (genotypes 2 and 3), and from 48 to 24 weeks (genotype 1) in case of hepatitis C virus (HCV) clearance at week 4, without reducing sustained virologic response (SVR). Conversely, prolonging treatment for 72 weeks in those with only a decrease of viral load at week 4, i.e. "slow responders" increases SVR rates by preventing relapse. In spite of such progress, over half of patients are relapsers or nonresponders. If the previous treatment was suboptimal, retreatment with higher doses or longer duration may be beneficial unless an individual was a 'null responder' previously. New promising anti-HCV molecules (antiproteases and antipolymerases), some with potent antiviral activity, are in phase II trials but appear to require the addition of IFN and ribavirin to maintain viral suppression. Other immunomodulatory agents such as new IFN or therapeutic vaccines and alternatives to ribavirin are also under development. Future regimens should improve efficacy and provide shorter and better-tolerated combination therapy.

Increasing genetic diversity of hepatitis C virus in haemophiliacs with human immunodeficiency virus coinfection

Patients with inherited bleeding disorders who received clotting factor concentrates before 1987 have high rates of hepatitis C virus (HCV) or HCV/human immunodeficiency virus (HIV) infection. To determine whether the persistent nature of HIV affects the genetic diversity of HCV by less selective pressure through the immunosuppression of HIV/HCV-coinfected patients, both the change of genetic diversity and selective pressure were examined in the HCV envelope genes (E1 and E2) of 325 genotype 1a subclones from eight HIV-positive and five HIV-negative patients with two time points (more than 6 years apart). To infer the genetic diversity of HCV in each patient, we used two approaches. One method was to estimate the difference of total evolutionary distances in the phylogenetic tree between the two time points, and another was to estimate the changes of genetic diversity along the time based on the coalescence theory. The two results indicate that the HIV-positive group has significantly more diverse population structure than the HIV-negative group. A comparative analysis of the synonymous and non-synonymous substitutions found that the HIV-positive group was subject to less selective pressure than the HIV-negative group. In conclusion, HIV-positive patients would have a more diversified HCV population than HIV-negative patients due to less selective pressure from the immune system.

When to start antiretroviral therapy

The current literature is controversial in providing evidence to determine the optimal time to initiate therapy among patients with HIV. However, there is evidence that initiating early treatment might provide benefits by treating primary HIV infection, preserving normal immune function, suppressing HIV viral replication, deferring clinical progression, and reducing HIV transmission. The biggest challenges in initiating treatment early are issues related with long-term management, including toxicities, adherence, and drug resistance. However, the availability of superior new antiretroviral drugs and simplified regimens, the development of effective treatment strategy, and further improvement of adherence through directly observed treatment are addressing the issues and changing the balance towards earlier treatment.

Reduction in liver-related hospital admissions and deaths in HIV-infected patients since the year 2002

Since the advent of highly active antiretroviral therapy (HAART), complications of chronic liver disease (CLD) have emerged as one of the leading causes of hospital admission and death among HIV-infected patients with chronic hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infections. The impact of CLD on hospital admissions and deaths in HIV-infected patients attended at one reference HIV hospital in Madrid during the last 9 years was analysed. All clinical charts from January 1996 to December 2004 were retrospectively examined. Demographics, discharge diagnosis, complications during inhospital stay and causes of death were recorded. A total of 2527 hospital admissions in 2008 distinct HIV-infected persons were recorded. Overall, 84% were iv drug users; mean age was 37 years and the mean CD4 count was 224 cells/muL. Both mean age and CD4 count significantly increased during the study period (P < 0.01). Overall, 42% of hospitalized patients were on antiretroviral therapy. Decompensated CLD was the cause of admission and/or developed during hospitalization in 345 patients (14%). Admissions caused by decompensated CLD increased significantly from 9.1% (30/329) in 1996 to 26% (78/294) in 2002. A significant steady decline occurred since then, being 11% (29/253) in the year 2004. Similarly, inhospital liver-related deaths were 9% (5/54) in 1996, peaked to 59% (10/17) in 2001 and declined to 20% (3/15) in the year 2004. Chronic hepatitis C was responsible for admissions and/or deaths in 73.5% of CLD cases. In conclusion, the rate of liver-related hospital admissions and deaths among HIV-infected patients peaked in the year 2002 and has steadily declined since then. A slower progression to liver cirrhosis in patients on HAART, avoidance of hepatotoxic antiretroviral drugs and more frequent use of anti-HCV therapy in HIV/HCV-coinfected patients could account for this benefit.

Antiretroviral medication considerations for individuals coinfected with HIV and hepatitis C virus

There is great need to treat HIV/hepatitis C virus (HCV)-coinfected individuals with both antiretroviral and anti-HCV pharmacotherapy. However, treatment for HIV may lead to hepatotoxicity, and there are potential interactions and synergistic effects between antiretrovirals and anti-HCV medications. The ideal antiretroviral therapy options for coinfected patients, in the setting of anti-HCV treatment, are unclear and present important challenges to clinicians. We review the current data on the use of antiretrovirals in HIV/HCV-coinfected patients and offer evidence-based recommendations on optimal selection and dosing of antiretroviral agents for this population.

Management of chronic hepatitis B and C in HIV-coinfected patients

One-third of HIV-infected individuals worldwide suffer from chronic hepatitis C virus (HCV) infection, but chronic hepatitis C affects more than 75% of HIV-positive subjects infected parenterally, such as haemophiliacs and intravenous drug users. Chronic hepatitis B virus (HBV) infection, on the other hand, occurs in 10% of HIV-infected persons, coinfection being more prevalent in Southeast Asia. There are two main reasons for considering HCV and HBV therapy as a priority in HIV-coinfected patients: first, the more rapid liver disease progression seen in this population, leading to end-stage liver disease complications, including hepatocellular carcinoma, at younger ages; and second, the higher risk of developing hepatotoxicity following the initiation of antiretroviral therapy in subjects with underlying chronic hepatitis than in HIV-monoinfected individuals. As highly active antiretroviral therapy (HAART) has dramatically improved the prognosis of those with HIV disease, the consequences of associated illnesses such as hepatitis B and C, which are currently among the leading causes of hospital admission and death in the HIV-infected population, have become more relevant. Therefore, the adequate management of viral hepatitis should now be considered a priority in HIV-coinfected patients. Several guidelines have recently been released in response to this demand. In this article, we discuss the most critical issues highlighted in these documents.

Effect of hepatitis C coinfection on discontinuation and modification of initial HAART in primary HIV care

OBJECTIVES

To estimate the effect of hepatitis C (HCV) coinfection on time to first occurrence of either discontinuation or modification of initial HAART among previously antiretroviral therapy-naive HIV-infected patients.

METHODS

The analysis included antiretroviral therapy-naive patients who initiated HAART prior to November 2003 and were participating in the University of North Carolina Center for AIDS Research, HIV/AIDS observational clinical cohort. The effect of HCV status on time to first occurrence of either HAART discontinuation or modification was assessed using Kaplan-Meier survival estimates and multivariable proportional hazards regression was used to estimate hazard ratios.

RESULTS

Of 296 patients initiating HAART, 22% were coinfected with HCV. During a median follow-up of 473 days [interquartile range (IQR), 167-940] from HAART initiation, 104 (35%) patients discontinued and 91 (31%) modified their first regimen. Reasons for discontinuation and modification were comparable by HCV serostatus and included treatment failure (12%), toxicity (41%), and barriers to adherence (47%). The median time to first occurrence of either discontinuation or modification among HCV-infected patients was 401 days (IQR, 128-821), and among HCV-uninfected patients was 493 days (IQR, 204-952) (P = 0.22). After adjustment for baseline demographic and clinical characteristics, the hazard ratio contrasting HCV-infected with HCV-uninfected patients was 1.39 (95% confidence interval, 0.95-2.03; P = 0.09).

CONCLUSION

HCV coinfection was only marginally associated with a shorter duration of an initial HAART regimen, suggesting optimization of a first HAART regimen may not appreciably depend on HCV serostatus.

Hepatitis C coinfection is independently associated with decreased adherence to antiretroviral therapy in a population-based HIV cohort

OBJECTIVE

To characterize the impact of hepatitis C (HCV) serostatus on adherence to antiretroviral treatment (ART) among HIV-infected adults initiating ART.

METHODS

The British Columbia HIV/AIDS Drug Treatment Program distributes, at no cost, all ART in this Canadian province. Eligible individuals used triple combination ART as their first HIV therapy and had documented HCV serology. Statistical analyses used parametric and non-parametric methods, including multivariate logistic regression. The primary outcome was > or = 95% adherence, defined as receiving > or = 95% of prescription refills during the first year of antiretroviral therapy.

RESULTS

There were 1186 patients eligible for analysis, including 606 (51%) positive for HCV antibody and 580 (49%) who were negative. In adjusted analyses, adherence was independently associated with HCV seropositivity [adjusted odds ratio (AOR), 0.48; 95% confidence interval (CI), 0.23-0.97; P = 0.003], higher plasma albumin levels (AOR, 1.07; 95% CI, 1.01-1.12; P = 0.002) and male gender (AOR, 2.53; 95% CI, 1.04-6.15; P = 0.017), but not with injection drug use (IDU), age or other markers of liver injury. There was no evidence of an interaction between HCV and liver injury in adjusted analyses; comparing different strata of HCV and IDU confirmed that HCV was associated with poor adherence independent of IDU.

CONCLUSIONS

HCV-coinfected individuals and those with lower albumin are less likely to be adherent to their ART.

Vertically acquired paediatric coinfection with HIV and hepatitis C virus

Both HIV and hepatitis C virus (HCV) can be transmitted from mother to child during pregnancy and delivery. Vertical transmission of HIV and HCV separately is most likely from HIV/HCV-coinfected mothers; however, transmission of both infections is less frequent. The effect of HCV coinfection on HIV-related disease remains unclear; whereas most studies indicate no effect, recent results suggest HCV in adults accelerates HIV progression. Little is known about how HIV coinfection affects HCV progression in children and the information available is based on small numbers of patients. Paediatric HIV treatment is extremely successful and it is vital to determine if HCV coinfection alters the effectiveness of this treatment. The hepatotoxicity of many HIV therapies and the possible negative impact of HCV on this treatment, alongside the interactions and contraindications of many HIV and HCV therapies, further limits the choice of paediatric treatments for coinfected children. Future research must therefore focus on vertically acquired HIV/HCV coinfection to inform treatment trials addressing coinfection management.

Expanding research on the role of alcohol consumption and related risks in the prevention and treatment of HIV/AIDS

This article is a review of some of the major epidemiological, behavioral, biological, and integrative prevention research issues and priorities in the area of HIV/AIDS and alcohol consumption. Drinking alcohol increases both the risk for infection with HIV and related illnesses and the morbidity and mortality of patients who progress to AIDS. New and improved measurement procedures have helped in assessment of the complex patterns of alcohol use, identification of intervening explanatory mechanisms for risk behaviors and contexts, and determination of intervention outcomes. Both the direct and indirect effects of alcohol misuse appear to be major contributors to both the risk for infection with HIV and the transmission of HIV/AIDS at the individual and population levels. There is increasing evidence that perhaps no level of alcohol consumption is "safe" for those who are HIV infected and receiving antiretroviral treatment. Interdisciplinary basic behavioral and biomedical research is needed to develop comprehensive culturally appropriate strategies for programs that can be effectively delivered in community contexts in the United States and abroad and that focus on the integration of our understanding of individual behaviors, high-risk group membership, biological mechanisms, and the social and physical environments that place individuals at risk for HIV infection. High-priority topics include improving adherence to antiretroviral medications, prevention of infection in young minority women in the United States, and treatment of HIV+ pregnant women who are alcohol abusers to prevent adverse fetal outcomes, which is an international focus in under-resourced settings in Africa.

Risks of Non-Accidental Mortality by Baseline CD4+ T-Cell Strata in Hepatitis-C-Positive and -Negative Individuals Initiating Highly Active Antiretroviral Therapy

Background

Patients coinfected with hepatitis C virus (HCV) and HIV experience higher mortality rates than patients infected with HIV alone. We designed a study to determine whether risks for later mortality are similar for HCV-positive and HCV-negative individuals when subjects are stratified on the basis of baseline CD4+ T-cell counts.

Methods

Antiretroviral-naive individuals, who initiated highly active antiretroviral therapy (HAART) between 1996 and 2002 were included in the study. HCV-positive and HCV-negative individuals were stratified separately by baseline CD4+ T-cell counts of 50 cell/μl increments. Cox-proportional hazards regression was used to model the effect of these strata with other variables on survival.

Results

CD4+ T-cell strata below 200 cells/μl, but not above, imparted an increased relative hazard (RH) of mortality for both HCV-positive and HCV-negative individuals. Among HCV-positive individuals, after adjustment for baseline age, HIV RNA levels, history of injection drug use and adherence to therapy, only CD4+ T-cell strata of <50 cells/μl (RH=4.60; 95% confidence interval [CI] 2.72–7.76) and 50–199 cells/μl (RH=2.49; 95% CI 1.63–3.81) were significantly associated with increased mortality when compared with those initiating therapy at cell counts >500 cells/μl. The same baseline CD4+ T-cell strata were found for HCV-negative individuals.

Conclusion

In a within-groups analysis, the baseline CD4+ T-cell strata that are associated with increased RHs for mortality are the same for HCV-positive and HCV-negative individuals initiating HAART. However, a between-groups analysis reveals a higher absolute mortality risk for HCV-positive individuals.

New paradigms in the management of HIV and hepatitis C virus coinfection

PURPOSE OF REVIEW

Chronic hepatitis C virus infection is currently one of the leading causes of morbidity and mortality in HIV-infected individuals, mainly in hemophiliacs and intravenous drug users. The bidirectional interferences between hepatitis C virus and HIV have clinical consequences and complicate the management of coinfected individuals.

RECENT FINDINGS

There is an increased rate of liver complications among coinfected patients due to the decrease in opportunistic infections resulting from the use of potent antiretroviral therapy and accelerated progression to liver cirrhosis in the HIV setting. Conversely, the risk of hepatotoxicity of antiretrovirals is higher in the presence of chronic hepatitis C. While the standard therapy for hepatitis C in HIV is the combination of pegylated interferon plus ribavirin, overall treatment responses are lower in HIV-coinfected than in hepatitis C virus-monoinfected patients. Moreover, interactions between ribavirin and HIV drugs (i.e. didanosine, zidovudine) are associated with higher risks of side effects.

SUMMARY

Given the accelerated progression to end-stage liver disease in coinfected patients, treatment of hepatitis C should be a priority. While hepatitis C therapy should not be denied in the absence of contraindication, it should be re-assessed at week 12 and therapy continued only in patients showing more than 2 log drops in viremia, to avoid side effects. Most recent data suggest that adequate selection of candidates, expert management of side effects, and prescription of appropriate ribavirin doses (in genotypes 1-4) and extending treatment (in genotypes 2-3) all might allow response rates in coinfected patients to approach those seen in hepatitis C virus-monoinfected individuals.

When to initiate antiretroviral therapy in HIV-1-infected adults: a review for clinicians and patients

One of the most controversial topics in the medical management of HIV disease is the optimal time to initiate highly active antiretroviral therapy (HAART) in HIV-1-infected adults. Premature exposure to antiretrovirals may precipitate early evolution of resistance and unnecessary side-effects, whereas remaining off HAART until late in the course of HIV disease may lead to reduced therapeutic benefits and elevated mortality. The lack of a randomised clinical trial to consider this issue has resulted in ongoing revision of expert recommendations and substantial variability between international consensus guidelines regarding the optimal time to initiate therapy. Since this uncertainty is a source of unease for both patients and clinicians, we summarise the latest evidence regarding the optimal time to initiate HAART with consideration of the potential benefits and drawbacks of starting HIV treatment at the different levels presently recommended in leading consensus guidelines.

Antiretroviral-associated hepatotoxicity

The use of highly active antiretroviral therapy has dramatically reduced HIV-associated morbidity and mortality. As a result, patients are often being treated longer and with more complex medical regimens than ever before, increasing the risk for drug interactions and toxicities. In particular, hepatotoxicity caused by antiretroviral use has become an increasingly appreciated potential complication of drug treatment. All classes of antiretrovirals have been reported to induce liver enzyme abnormalities. However, certain antiretrovirals appear much more likely to be associated with drug-induced hepatotoxicity. The risk of antiretroviral-related hepatotoxicity may be associated with patient-specific risk factors, including pre-existing viral hepatitis, baseline elevated liver function test results, female gender, and substance abuse. In addition, complex drug-drug interactions may potentate the risk of antiretroviral-associated hepatotoxicity. Coinfection with hepatitis B or hepatitis C appears to increase the risk of antiretroviral-related hepatotoxicity.