Insulin resistance impairs rapid virologic response in HIV/hepatitis C virus coinfected patients on peginterferon-alfa-2a

Addition of nitazoxanide to PEG-IFN and ribavirin to improve HCV treatment response in HIV-1 and HCV genotype 1 coinfected persons naïve to HCV therapy: results of the ACTG A5269 trial

BACKGROUND

We hypothesized that nitazoxanide (NTZ) added to pegylated interferon alfa-2a (PEG-IFN) and weight-based ribavirin (WBR) would improve hepatitis C virus (HCV) virologic responses in HCV treatment-naïve HIV-1/HCV genotype 1 coinfected persons.

METHODS

Prospective, single-arm study in which subjects received 4-week lead-in (NTZ 500 mg twice daily) followed by 48 weeks of NTZ, PEG-IFN, and WBR. We compared the HCV virologic responses of these subjects to historical controls from the completed ACTG study A5178 who received PEG-IFN and WBR and had similar subject characteristics. Primary endpoints were early virologic response and complete early virologic response (EVR and cEVR).

RESULTS

Among 67 subjects (78% male; 48% Black; median age, 50 years), EVR was achieved in 65.7% (90% CI, 55.0%-75.3%), cEVR in 38.8% (28.8%-49.6%). and SVR in 32.8% (23.4%-43.5%). EVR was higher with NTZ (51.4% in A5178; P = .03), but the sustained virologic response (SVR) proportion was similar (27.3% in A5178; P = .24). In contrast to A5178, SVR was similar across IL28B genotypes. Overall, NTZ was safe and well-tolerated.

CONCLUSION

Whereas EVR proportion improved significantly in this pilot study, the addition of NTZ to PEG-IFN/WBR did not significantly improve SVR compared to historical controls. NTZ may be associated with an attenuation of the effect of IL28B on HCV treatment response.

Insulin resistance impairs viral dynamics independently of ethnicity or genotypes

BACKGROUND AND AIM

Data concerning the influence of insulin resistance (IR) and ethnicity on early phases of viral kinetics after initiation of peginterferon plus ribavirin in treatment-naive, chronic hepatitis C (CHC) patients are limited.

METHODS

A total of 263 nondiabetic CHC patients treated with peginterferon plus ribavirin were enrolled for analysis from an Egyptian and Spanish center. IR was evaluated by homeostasis model assessment (HOMA)-IR. Hepatitis C virus (HCV) RNA levels were measured at baseline, 48 hours, 2, 4, and 12 weeks after treatment initiation. Sustained virological response (SVR) was examined 24 weeks after therapy discontinuation.

RESULTS

Baseline HOMA-IR strongly influenced 48 hours viral dynamics. HCV-RNA decay observed at 48 hours after the first injection of peginterferon was significantly lower (0.91±0.51 log) in patients with HOMA ≥2 compared with those with HOMA <2 (1.8±0.95 log, P=0.005) this effect was independent of stage of liver fibrosis, HCV genotype, and ethnicity. These differences remained with several cutoffs such as HOMA >3 or HOMA >4. Multivariate analysis identified baseline insulin levels as the main independent variable affecting the 48-hour response in addition to baseline HCV-RNA. The difference in early viral kinetics between patients with HOMA ≥2 or <2 is associated with a significant difference in the percentage of patients achieving both rapid virological response and SVR.

CONCLUSIONS

IR is a major determinant of the early viral kinetic response to peginterferon plus ribavirin, which has a great impact on subsequent rapid virological response and SVR in CHC patients. This suggests that strategies to improve IR may have a positive effect on SVR and may be early monitored.

Current treatment for chronic hepatitis C virus/HIV-infected individuals: the role of pegylated interferon-alpha and ribavirin

PURPOSE OF REVIEW

Liver disease is an important cause of morbidity and mortality in the era of combination antiretroviral therapy in HIV/hepatitis C virus (HCV) co-infected patients. This review highlights the role of pegylated interferon-alpha (peg-IFN) and ribavirin (RBV) therapy and examines factors associated with response and strategies to maximize responses.

RECENT FINDINGS

HCV viral clearance is lower in HIV co-infected patients than in HCV mono-infected patients. However, in patients who attain sustained response there is clinical benefit in terms of liver disease associated morbidity and mortality and treatment is costeffective. Predictors of response appear similar, although there are a number of modifiable patient-associated and HIV-associated factors that could be addressed. Moreover, the use of weight-based RBV and treatment length guided by early viral responses improve response rate. Avoidance of drug-drug interactions and use of haematopoietic growth factors reduce adverse events and dose reductions and ultimately increase response rates. Very early prediction of treatment futility is promising. Induction dosing strategies have not yielded positive results, though twice weekly peg-IFN-alpha-2a induction therapy merits further investigation.

SUMMARY

Peg-IFN/RBV therapy plays an important role in the management of HCV in HIV-infected patients. Efforts to maximize response to current therapy need to continue while we await new therapies.

Steatosis and insulin resistance in response to treatment of chronic hepatitis C

This review will focus on the impact of steatosis and insulin resistance on the response to antiviral therapy for chronic hepatitis C. Hepatitis C virus (HCV) infection is known to have direct and/or indirect effects on lipid and glucose metabolism, leading to, among other disturbances, steatosis and insulin resistance, respectively. Some of these disturbances have a marked HCV genotype distribution. For example, on average, patients with HCV genotype 3 have the highest prevalence and severity of viral fatty liver. On the other hand, the current global spread of the metabolic syndrome represents a formidable cofactor of morbidity in HCV-related chronic liver disease. Thus, the pathogenesis of steatosis and insulin resistance in patients with chronic hepatitis C may often be dual, i.e. viral and metabolic. This distinction is relevant because the effect (if any) of steatosis or insulin resistance on the response to antiviral agents seems to depend on their pathogenesis. Accumulating data suggest that viral fatty liver may not impact on response to therapy, while metabolic steatosis does. Similarly, viral insulin resistance may not reduce the rate of response to therapy to the same extent that metabolic insulin resistance does. Some implications for patient management are discussed.

The role of insulin resistance in HIV/hepatitis C virus-coinfected patients

PURPOSE OF REVIEW

Insulin resistance, HIV, antiviral drugs and hepatitis C virus (HCV) infection contribute to a complex interaction involving the metabolic syndrome. The objective of this review was to explore the meaning of insulin resistance in HIV-HCV-coinfected patients and how it may impact on sustained virological response (SVR) and disease progression.

RECENT FINDINGS

In the HIV/HCV coinfection setting, insulin resistance seems to be associated with a reduction in rapid virological response and SVR to pegylated interferon and ribavirin, both in naive and treatment experienced patients. A recent meta-analysis demonstrated insulin resistance impairs SVR rate with an odds ratio 0.47 (95% confidence interval 0.31-0.71). However, many confounding factors may promote contradictory results. Prevalence of insulin resistance depends on surrogate markers of insulin resistance and the threshold for defining impaired insulin sensitivity. For example, homeostasis model for the assessment of insulin resistance may be influenced by both methods of insulin measurement and interpretation. Insulin sensitizers, lifestyle changes and improvement in the use of protease inhibitors should be evaluated in the management of coinfected patients.

SUMMARY

Insulin resistance is common finding in patients with HIV/HCV coinfection, with wide clinical consequences including progression of hepatic fibrosis and reduction in the response to antiviral treatment. Our understanding of this relationship continues to improve. More prospective studies are required to improve future management.

Current understanding of insulin resistance in hepatitis C

Important breakthroughs have been made in recent years into understanding the close interaction between hepatitis C virus (HCV) infection and glucose homeostasis. Both cross-sectional and longitudinal studies have demonstrated that infection with HCV is associated with an increased risk of developing insulin resistance and Type 2 diabetes. A direct effect of HCV on hepatocyte insulin signaling has been shown in experimental models. Some preliminary observations seem to suggest that indirect mechanisms involving extrahepatic organs might also play a role. The interaction between HCV and glucose metabolism has significant clinical consequences. Insulin resistance and Type 2 diabetes not only accelerate the histological and clinical progression of chronic hepatitis C, but also reduce the virological response to IFN-α-based therapy. Thus, understanding the mechanisms underlying HCV-associated glucose metabolism derangements is of paramount interest in order to improve the clinical management of chronic hepatitis C. This article will focus on the studies that consistently argue in favor of an interrelation between HCV and insulin resistance and will highlight the latest discoveries in this field.

IL28B polymorphisms, IP-10 and viral load predict virological response to therapy in chronic hepatitis C

BACKGROUND

Hepatitis C virus (HCV) is a major cause of chronic liver disease, cirrhosis and hepatocellular carcinoma and the identification of the predictors of response to antiviral therapy is an important clinical issue.

AIM

To determine the independent contribution of factors including IL28B polymorphisms, IFN-gamma inducible protein-10 (IP-10) levels and the homeostasis model assessment of insulin resistance (HOMA-IR) score in predicting response to therapy in chronic hepatitis C (CHC).

METHODS

Multivariate analysis of factors predicting rapid (RVR) and sustained (SVR) virological response in 280 consecutive, treatment-naive CHC patients treated with peginterferon alpha and ribavirin in a prospective multicentre study.

RESULTS

Independent predictors of RVR were HCV RNA <400 000 IU/mL (OR 11.37; 95% CI 3.03-42.6), rs12980275 AA (OR 7.09; 1.97-25.56) and IP-10 (OR 0.04; 0.003-0.56) in HCV genotype 1 patients and lower baseline γ-glutamyl-transferase levels (OR=0.02; 0.0009-0.31) in HCV genotype 3 patients. Independent predictors of SVR were rs12980275 AA (OR 9.68; 3.44-27.18), age <40 years (OR=4.79; 1.50-15.34) and HCV RNA <400 000 IU/mL (OR 2.74; 1.03-7.27) in HCV genotype 1 patients and rs12980275 AA (OR=6.26; 1.98-19.74) and age <40 years (OR 5.37; 1.54-18.75) in the 88 HCV genotype 1 patients without a RVR. RVR was by itself predictive of SVR in HCV genotype 1 patients (OR 33.0; 4.06-268.32) and the only independent predictor of SVR in HCV genotype 2 (OR 9.0, 1.72-46.99) or genotype 3 patients (OR 7.8, 1.43-42.67).

CONCLUSIONS

In HCV genotype 1 patients, IL28B polymorphisms, HCV RNA load and IP-10 independently predict RVR. The combination of IL28B polymorphisms, HCV RNA level and age may yield more accurate pre-treatment prediction of SVR. HOMA-IR score is not associated with viral response.

The homeostasis model assessment of the insulin resistance score is not predictive of a sustained virological response in chronic hepatitis C patients

OBJECTIVES

To investigate the independent association between the homeostasis model assessment of the insulin resistance (HOMA-IR) score and rapid virological response (RVR) and sustained virological response (SVR) in chronic hepatitis C (CHC).

METHODS

Observational prospective cohort study of 412 CHC patients [59% males; mean age 45 years; genotype 1 (44%), 2 (32%), 3 (19%) and 4 (5%)] treated with pegylated interferon α plus ribavirin.

RESULTS

A HOMA-IR ≥2.0 was present in 49% and a metabolic syndrome in 4% of patients. By multivariate analysis, independent predictors of SVR were the lack of advanced fibrosis (≥F3) in genotype 1 and a lower body mass index in genotype 3 patients. In the subgroup of patients in whom HCV-RNA was evaluated at week 4 (n = 281), independent predictors of RVR were HCV-RNA <700,000 IU/ml, age <40 years and lower aspartate aminotransferase:alanine aminotransferase ratio in genotype 1 and baseline HOMA-IR ≤2 in genotype 3 patients. No predictive factor of RVR was identified among genotype 2 patients. RVR was the strongest predictor of SVR among genotype 1 or 3 patients.

CONCLUSIONS

In this series of treatment-naïve, Caucasian CHC patients at a low risk for the metabolic syndrome, HOMA-IR is not a predictor of SVR, irrespective of the HCV genotype, although it may predict RVR in genotype 3 infection.

Insulin resistance predicts re-treatment failure in an efficacy study of peginterferon-α-2a and ribavirin in HIV/HCV co-infected patients

BACKGROUND & AIMS

Few studies evaluated the efficacy of HCV re-treatment and the predictors of response in HIV/HCV co-infected patients. The role of insulin resistance as a predictor of response in this population is unknown. The aim of this study is to evaluate the safety and efficacy of pegylated interferon-α-2a and ribavirin in re-treatment of HIV/HCV co-infected patients, predictors of sustained virological response, including insulin resistance, and the relationship between insulin resistance and liver histology.

METHODS

This prospective, multi-centered study included HIV/HCV co-infected patients with prior interferon-based treatment failure. Patients received pegylated interferon-α-2a and ribavirin for 48 weeks. Serum HCV RNA was measured 24 weeks post treatment to assess sustained virological response. Insulin resistance was defined as HOMA-IR >2. Correlations between baseline insulin resistance and steatosis, and/or cirrhosis were determined.

RESULTS

Sustained virological response was achieved in 14/96 (15%) patients. 35% of patients with HOMA-IR < 2 (6/17) achieved sustained virological response vs 14% (5/36) of those with HOMA-IR between 2-4, and 7% (3/41) of those with HOMA-IR > 4 (p = 0.01). In multivariable analysis, insulin resistance and log₁₀ HCV RNA were negatively associated with sustained virological response [AOR 0.17; 95% CI 0.05-0.64, p = 0.009, and AOR 0.36; 95% CI 0.14-0.93, p = 0.04, respectively]. Steatosis and cirrhosis correlated with insulin resistance (p = 0.02 and 0.03, respectively) but neither independently predicted sustained virological response. Discontinuations due to severe adverse events occurred in 8% of cases, and 2 patients died of unrelated causes.

CONCLUSIONS

In HIV/HCV co-infected patients undergoing re-treatment, sustained virological response rate is low; those patients without insulin resistance are significantly more likely to achieve sustained virological response.

How to use virological tools for the optimal management of chronic hepatitis C

Approximately 180 million individuals are chronically infected with hepatitis C, which is strongly associated with the development of cirrhosis, end-stage liver disease and hepatocellular carcinoma. Several virological tools (anti-HCV antibody assays, measurement of HCV-RNA, HCV-genotyping) are useful in management of hepatitis C infected patients. The primary goal of antiviral therapy in chronic hepatitis C is a sustained virological response (SVR). The HCV genotype should be determined in every patient considered for antiviral therapy because the currently recommended treatment duration and ribavirin doses differ among HCV genotypes. Exact subtyping might gain increased importance for future therapies with direct-acting antiviral agents (DAA) because of differences of antiviral activities and barriers to resistance among HCV subtypes. Monitoring HCV RNA by a highly sensitive assay (LOD ≤ 15 IU/ml) is the basis for management of response guided therapy of chronic hepatitis C with pegylated IFN plus ribavirin. Rules for early discontinuation of antiviral therapy in non-responders and determination of optimal treatment durations in virologic responders have been developed for application of individualized treatment strategies.

Insulin resistance impairs response to interferon plus ribavirin in patients coinfected with HIV and hepatitis C virus

BACKGROUND/AIMS

Controversy exists about whether insulin resistance (IR) affects response to treatment of hepatitis C. We evaluated the effect of IR on sustained virologic response (SVR) in HIV/hepatitis C virus (HCV)-coinfected patients treated with interferon plus ribavirin.

METHODS

We reviewed the clinical records of HIV/HCV-coinfected patients who received interferon plus ribavirin at our institution between July 2000 and March 2007. IR was defined as a homeostasis model assessment ≥ 3.8. SVR was defined as an undetectable HCV RNA at 24 weeks after the end of treatment. Efficacy was evaluated using an on-treatment (OT) analysis. Multivariate logistic regression analysis was used to evaluate factors associated with SVR.

RESULTS

During the study period, 218 patients were treated with interferon plus ribavirin; IR at baseline was available for 162 patients, and 134 were included in the OT analysis; HCV genotype (G) 1/4, 67%; F3-F4 fibrosis, 36%; IR 31%. SVR was achieved in 67 patients (50%) (79% in G 2/3 vs. 38% in G 1/4). IR was associated with a lower SVR [odds ratio (OR), 0.33; 95% confidence interval (CI): 0.15-0.72; P = 0.006). The independent variables related to SVR were genotype 2/3 (OR, 6.7; 95% CI: 2.71-16.98; P < 0.001), absence of IR at baseline (OR, 3.3; 95% CI: 1.36-8.26; P = 0.008), and nadir CD4 T-cell count (OR, 1.002; 95% CI: 1.00-1.00; P = 0.047).

CONCLUSIONS

Our data suggest that IR is an important determinant of SVR in HIV/HCV-coinfected patients treated with interferon plus ribavirin. Strategies to modify IR should be explored to enhance SVR during anti-HCV therapy.

Potential treatment options and future research to increase hepatitis C virus treatment response rate

Hepatitis C virus (HCV) is a liver-tropic blood-borne pathogen that affects more than 170 million people worldwide. Although acute infections are usually asymptomatic, up to 90% of HCV infections persist with the possibility of long-term consequences such as liver fibrosis, cirrhosis, steatosis, insulin resistance, or hepatocellular carcinoma. As such, HCV-associated liver disease is a major public health concern. Although the currently available standard of care therapy of pegylated interferon α plus ribavirin successfully treats infection in a subset of patients, the development of more effective, less toxic HCV antivirals is a health care imperative. This review not only discusses the limitations of the current HCV standard of care but also evaluates upcoming HCV treatment options and how current research elucidating the viral life cycle is facilitating the development of HCV-specific therapeutics that promise to greatly improve treatment response rates both before and after liver transplantation.

Insulin resistance predicts rapid virologic response to peginterferon/ribavirin combination therapy in hepatitis C genotype 4 patients

OBJECTIVES

In patients with chronic hepatitis C (CHC) of genotype 4, the predictors of rapid virologic response (RVR) have not been determined adequately. We aimed to assess which pretreatment variables might predict an RVR and a sustained virologic response (SVR).

METHODS

A total of 131 non-diabetic, genotype 4 CHC patients were enrolled for analysis and treated with peginterferon-alpha-2b/ribavirin. Insulin resistance (IR) was evaluated by homeostasis model assessment-IR (HOMA-IR). Hepatitis C virus (HCV)-RNA levels were measured at baseline, during therapy and at follow-up.

RESULTS

The overall SVR rate was 60.3%. The SVR rate in patients with an RVR was 100%. Age, HOMA-IR, fibrosis, severity of the steatosis, and HCV viral load were all significantly associated with RVR in the univariate analysis. After logistic regression, both HOMA-IR (odds ratio: 0.12, P=0.002) and HCV viral load (odds ratio: 1.43, P=0.02) remained independent variables associated with RVR. Age, HOMA-IR, viral load, fibrosis, RVR, and "complete" early virological response were all significantly associated with SVR in the univariate analysis. After logistic regression, fibrosis (odds ratio: 5.23, P=0.007), HOMA-IR (odds ratio: 14.29, P=0.004), and viral load (odds ratio: 0.16, P=0.005) were independent factors associated with SVR. By linear regression, body mass index (P=0.001) and waist circumference (P=0.0003) were independently associated with HOMA-IR.

CONCLUSIONS

IR is a major determinant of both RVR and SVR in genotype 4 CHC patients. HOMA-IR would seem to be a useful tool for predicting the response to therapy.

Impact of hyperglycaemia and cholesterol levels on the outcome of hepatitis C virus (HCV) treatment in HIV/HCV-coinfected patients

OBJECTIVES

High serum total cholesterol and low-density lipoprotein (LDL) levels have been demonstrated to increase the probability of a sustained viral response (SVR) in chronic hepatitis C. Conversely, insulin resistance reduces SVR rates. We investigated the influence of baseline glucose and lipid values on the outcome of hepatitis C virus (HCV) treatment in HIV-1 infected subjects.

METHODS

We retrospectively reviewed the charts of HIV/HCV-coinfected patients treated with an interferon-based regimen from 2002 to 2008. Fasting glucose levels and total cholesterol, LDL and triglyceride levels were recorded prior to the initiation of treatment.

RESULTS

Of the 96 patients enrolled in the study, 36 (37.5%) had genotype 1, 48 (50%) genotype 2 or 3 and 12 (12.5%) genotype 4. SVR was obtained in 25% (nine of 36) and 70% (42 of 60) of patients with genotype 1 and other genotypes, respectively. In the multivariate analysis, the independent predictors of SVR were: genotype other than genotype 1 [adjusted odds ratio 9.64, confidence interval (CI) 2.7-34.3; P<0.0001], HCV viraemia [adjusted odds ratio 0.36, CI 0.15-0.9; P=0.028], fasting glucose > or =100 mg/dL [adjusted odds ratio 0.13, CI 0.034-0.51; P=0.003], and cholesterol level > or =190 mg/dL [adjusted odds ratio 5.96, CI 1.6-22.3; P=0.008].

CONCLUSIONS

Higher baseline serum glucose and cholesterol levels may be significant prognostic indicators for anti-HCV treatment outcome in HIV/HCV-coinfected patients.

Pioglitazone improves virological response to peginterferon alpha-2b/ribavirin combination therapy in hepatitis C genotype 4 patients with insulin resistance

BACKGROUND & AIM

Insulin resistance (IR) affects sustained virological response (SVR). The use of insulin-sensitizing agents has been proposed to improve therapy outcome. The safety and efficacy of pioglitazone on insulin sensitivity and SVR in treatment-naïve patients with chronic hepatitis C (CHC) genotype 4 with IR receiving standard antiviral therapy were evaluated in a randomized-controlled study.

METHODS

Ninety-seven previously untreated patients with CHC and IR [homeostasis model assessment (HOMA>2)] were randomly assigned into two arms; (arm A; n=48) were given pioglitazone 30 mg/day combined with peginterferon (Peg-IFN)-alpha-2b/ribavirin (RBV) for 48 weeks, and (arm B; n=49) were given standard of care (Peg-IFN-alpha-2b/RBV for 48 weeks); HOMA index and hepatitis C virus RNA (HCV RNA) levels were measured at baseline, during therapy and follow-up. Treatment was stopped in patients without an early virological response or those who were HCV RNA positive at 24 weeks.

RESULTS

Baseline data of both groups were comparable, with no significant statistical differences. The percentages of rapid virological response (RVR) and SVR were significantly higher in patients given triple therapy compared with standard of care (27.08 vs. 6.1%; P=0.006 and 60.4 vs. 38.7%; P=0.04 respectively); patients in arm A showed a greater decrease in the HOMA index than those in arm B (-1.8 +/- 0.3, -2.1 +/- 0.3 vs. -1.1 +/- 0.6, -1.3 +/- 0.7) at week 24 and at the end of follow-up (P=0.001 at both time points). The triple therapy was well tolerated.

CONCLUSIONS

A combination of pioglitazone, Peg-IFN-alpha-2b and ribavirin increased RVR, SVR and decreased IR, compared with patients given Peg-IFN plus ribavirin without an increase in adverse events.

Practice guidelines for the treatment of hepatitis C: recommendations from an AISF/SIMIT/SIMAST Expert Opinion Meeting

It is increasingly clear that a tailored therapeutic approach to patients with hepatitis C virus infection is needed. Success rates in difficult to treat and low-responsive hepatitis C virus patients are not completely satisfactory, and there is the need to optimise treatment duration and intensity in patients with the highest likelihood of response. In addition, the management of special patient categories originally excluded from phase III registration trials needs to be critically re-evaluated. This article reports the recommendations for the treatment of hepatitis C virus infection on an individual basis, drafted by experts of three scientific societies.

Insulin resistance predicts rapid virological response in non-diabetic, non-cirrhotic genotype 1 HCV patients treated with peginterferon alpha-2b plus ribavirin

BACKGROUND/AIMS

The rapid decline in hepatitis C virus RNA is crucial for determining the outcome of therapy in patients with genotype 1 chronic hepatitis C. However, the variables influencing the early phase of viral decay are still largely unexplored. We aimed to assess which pre-treatment variable may predict rapid virologic response (RVR) and sustained virologic response (SVR).

METHODS

We evaluated 90 consecutive non-diabetic patients with genotype 1 chronic hepatitis C without cirrhosis, treated with peginterferon alpha-2b plus ribavirin. Viral load (COBAS Amplicore, Roche) was measured at 1, 4 and 12 weeks after starting treatment, and then 24 weeks after the end of treatment.

RESULTS

The overall SVR was 47%. The SVR in patients with RVR was 100%. Age, GGT levels, viral load, steatosis, fibrosis and HOMA-IR were significantly associated with RVR in univariate analysis. After logistic regression, HOMA-IR proved to be the strongest independent predictor of RVR (OR 0.37, 95% CI: 0.16-0.89; p=0.027), whereas fibrosis had a weaker independent association with RVR (OR 0.32, 95% CI: 0.1-1.04; p=0.057). Among the eight pre-treatment variables, both BMI and steatosis were significantly associated with HOMA-IR, either in univariate or in multivariate analyses.

CONCLUSIONS

Our data suggest that insulin resistance is strongly associated with RVR, thus reflecting the important role played by metabolic factors in the early phase of viral kinetics. HOMA-IR would appear to be a useful tool in predicting RVR and should be evaluated at baseline in all chronic hepatitis C patients before initiating antiviral treatment.

Impact of obesity, steatosis and insulin resistance on progression and response to therapy of hepatitis C

Clinical progression of chronic hepatitis C depends on several cofactors, which also have a negative affect on the rate of response to interferon-alpha-based therapy. Given the current worldwide prevalence of the metabolic syndrome, the impact of obesity and insulin resistance, and of their histopathological correlate, hepatic steatosis, on the natural history and management of chronic hepatitis C is undoubtedly very important. We will review some of the current knowledge on the clinical consequences of overweight/obesity, steatosis and insulin resistance on chronic hepatitis C, and discuss how this issue may be dealt with in clinical practice.

Hepatitis C virus infection: molecular pathways to steatosis, insulin resistance and oxidative stress

The persistent infection with hepatitis C virus is a major cause of chronic liver disease worldwide. However, the morbidity associated with hepatitis C virus widely varies and depends on several host-related cofactors, such as age, gender, alcohol consumption, body weight, and co-infections. The objective of this review is to discuss three of these cofactors: steatosis, insulin resistance and oxidative stress. Although all may occur independently of HCV, a direct role of HCV infection in their pathogenesis has been reported. This review summarizes the current understanding and potential molecular pathways by which HCV contributes to their development.

Influence of insulin resistance on hepatic fibrosis and steatosis in hepatitis C virus (HCV) mono-infected compared with HIV-HCV co-infected patients

BACKGROUND

Insulin resistance (IR), the major feature of the metabolic syndrome, is also common in patients with chronic HCV infection. Liver fibrosis and steatosis are known potential outcome of chronic hepatitis B or C infection. Studies have shown that HIV positive individuals co-infected with HCV have more rapid live disease progression than those with HIV alone. Few data have reported the influence of IR on steatosis and fibrosis in the context of HIV-HCV coinfection.

AIM

To test the association among insulin resistance (IR), liver fibrosis and liver steatosis in HIV-HCV and HCV-infected patients.

PATIENTS AND METHODS

A total of 170 HIV-HCV-infected patients matched by age, gender and genotype with 170 HCV mono-infected patients were included. Patients were considered to be IR when the homeostasis model assessment of IR >2. Significant fibrosis was considered if METAVIR >or=F2 and significant steatosis if >or=10%.

RESULTS

Insulin resistance was independently associated in HCV patients with fibrosis [odds ratio (OR) = 2.04 (95% CI 1.02-4)], a body mass index (BMI) >25 kg/m(2) [OR = 3.33 (1.47-7.69)] and steatosis [OR = 3.33 (1.67-6.67)]. Fibrosis >or=F2 was associated in HCV patients with high liver activity grade (>or=A2) [OR = 8.33 (3.85-16.67)], male gender [OR = 3.03 (1.33-7.14)] and IR [OR = 2.44 (1.15-5)]. In HIV-HCV patients, >or=A2 [OR = 5.56 (1.64-20)] was associated with fibrosis. Steatosis >or=10% was associated in HCV patients with IR [OR = 3.13 (1.59-6.25) and >or=F2 (OR = 2.22 (1.15-4.17)]. In HIV-HCV, a BMI >25 kg/m(2) [OR = 3.85 (1.64-9.10)], >or=A2 [OR = 2.16 (1.02-4.55); P = 0.044] and nucleoside reverse transcriptase inhibitor [OR = 3.61 (1.19-10.96); P = 0.023] were independently associated with significant liver steatosis.

CONCLUSIONS

Insulin resistance is associated with liver fibrosis and steatosis in HCV mono-infected, but not in HIV-HCV co-infected patients. Significant liver fibrosis is associated with IR independent of liver steatosis only in HCV mono-infected patients.

Hepatitis C virus and type 2 diabetes

This review focuses on the relationship between hepatitis C virus (HCV) infection and glucose metabolism derangements. Cross-sectional and longitudinal studies have shown that the chronic HCV infection is associated with an increased risk of developing insulin resistance (IR) and type 2 diabetes (T2D). The direct effect of HCV on the insulin signaling has been analyzed in experimental models. Although currently available data should be considered as preliminary, HCV seems to affect glucose metabolism via mechanisms that involve cellular pathways that have been implicated in the host innate immune response. IR and T2D not only accelerate the histological and clinical progression of chronic hepatitis C, but also reduce the early and sustained virological response to interferon-alpha-based therapy. Thus, a detailed knowledge of the mechanisms underlying the HCV-associated glucose metabolism derangements is warranted, in order to improve the clinical management of chronic hepatitis C patients.

Insulin resistance is not a relevant predictor of sustained virological response to pegylated interferon plus ribavirin in HIV/HCV co-infected patients

BACKGROUND/AIMS

To evaluate the possible influence of baseline insulin resistance in sustained virological response.

METHODS

One hundred and fifty-five consecutive individuals from a multicentric cohort of HIV/HCV co-infected patients who underwent therapy with pegylated interferon plus ribavirin were included. The main outcome variable was sustained virological response, defined as undetectable plasma HCV RNA at week 24 after the end of the therapy. Insulin resistance was determined using the HOMA method.

RESULTS

Sustained virological response was achieved in 55 (36%) patients. Forty-two (38%) patients with a HOMA lower than 4 developed sustained virological response vs 13 (29%) of those with a HOMA above 4 (p=0.27). Analyses restricted to patients harbouring genotype 1 or 4 showed similar rates of sustained virological response among patients with a HOMA below and above 4 [19 (27%) vs 7 (24%); p=0.8]. In the multivariate analysis, genotype 3 [AOR 9.26; 95% CI 3.03-28.30; p<0.0001], a baseline HCV viral load below 600.000IU/mL [AOR 2.97; 95% CI 1.03-8.57; p=0.04] and baseline LDL cholesterol above 100mg/dL [AOR 6.62; 95% CI 1.97-22.19; p=0.002] were independently associated with sustained virological response.

CONCLUSIONS

Insulin resistance is not a relevant predictor of sustained virological response to pegylated interferon plus ribavirin in HIV/HCV co-infected patients.