- Email: [email protected]
ribavirin combination therapy in chronic hepatitis C patients
Journal of Hepatology 50 (2009) 712–718 www.elsevier.com/locate/jhep
Insulin resistance predicts response to peginterferonalpha/ribavirin combination therapy in chronic hepatitis C patientsq Chia-Yen Dai1,2,3, Jee-Fu Huang1,4, Ming-Yen Hsieh1, Nai-Jen Hou1,4, Zu-Yau Lin1,2, Shinn-Chern Chen1,2, Ming-Yuh Hsieh1,2, Liang-Yen Wang1,2, Wen-Yu Chang1,2, Wan-Long Chuang1,2,*, , Ming-Lung Yu1,2,3, 1
Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, No. 100, Tzyou 1st Rd, Kaohsiung 807, Taiwan 2 Faculty of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 3 Department of Occupational and Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 4 Department of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
See Editorial, pages 648–651
Background/Aims: Insulin resistance (IR) might be associated with hepatitis C virus (HCV) infection. This study aimed to elucidate impact of IR and beta-cell function on the response to peginterferon-alpha (PEG-IFN)/ribavirin combination therapy in chronic hepatitis C (CHC) patients. Methods: Three hundred and thirty patients without overt diabetes were treated with combination therapy with (PEG-IFN)/ribavirin for 24 weeks. The IR and beta-cell function were evaluated by homeostasis model assessment of IR (HOMA-IR) and homeostasis model assessment of beta-cell function (HOMA-beta) before treatment. Results: HCV genotype, pretreatment HCV RNA level and pretreatment HOMA-IR, but not HOMA-beta, were independent factors associated with sustained virologic response (SVR). In 150 patients with genotype 1b infection, pretreatment HCV RNA level, HOMA-IR and age were independent predictors for SVR. The significantly lower SVR rate in high HOMA-IR patients was observed in 76 patients with high HCV RNA levels (P400,000 IU/mL) who were defined as ‘difficult-to-treat’ patients. The mean HOMA-IR of ‘difficult-to-treat’ patients was significantly lower in 42 sustained responders than in 34 non-responders. Conclusions: IR was associated with SVR to (PEG-IFN)/ribavirin therapy for CHC, especially among ‘difficult-to-treat’ patients. These findings suggested clinical application of pretreatment HOMA-IR could enable treatment outcome to be predicted and treatment regimens to be determined. Ó 2009 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. Keywords: Chronic hepatitis C; Combination therapy; Genotype; Insulin resistance; The homeostasis assessment model
Received 27 July 2008; received in revised form 4 December 2008; accepted 9 December 2008; available online 6 February 2009 Associate Editor: F. Negro q The authors who have taken part in the research of this paper declared that they do not have a relationship with the manufacturers of the drugs involved either in the past or present and they did not receive funding from the manufacturers to carry out their research. * Corresponding author. Tel.: +886 7 3121101x7475; fax: +886-7-3234553. E-mail address: fi[email protected] (W.-L. Chuang). These authors contributed equally to this work. Abbreviations: ALT, alanine aminotransferase; anti-HCV, HCV antibody; FPG, fasting plasma glucose; BMI, body mass index; CHC, chronic hepatitis; HBsAg, hepatitis B surface antigen; SVR, sustained virologic response; HOMA, homeostasis model assessment; IR, insulin resistance; DM, diabetes mellitus; HAI, histological activity index 0168-8278/$36.00 Ó 2009 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.jhep.2008.12.017
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
1. Introduction Hepatitis C virus (HCV) has hepatotropic and lymphotropic characteristics leading to a wide spectrum of extrahepatic manifestations [1,2]. The association between a higher prevalence of type 2 diabetes mellitus (DM), with multifactorial pathogenetic mechanisms, and HCV infection has been reported [3–7]. In development of glucose abnormalities, insulin resistance (IR) and alteration of b-cell function have an important role. IR, caused by many metabolic factors, is also a common feature of disturbed carbohydrate metabolism in liver disease with or without cirrhosis, and precedes the development of type 2 DM [8,9]. The associations between IR and the clinical features of chronic hepatitis C (CHC) have been observed. Hui et al. [10] reported that HCV may induce IR irrespective of the severity of liver disease and IR may be associated with severe hepatic fibrosis and contribute to fibrotic progression in chronic HCV infection, as shown in other studies [10–12]. Combination therapy with peginterferon-alpha (PEG-IFN)/ribavirin has been recommended as standard therapy for patients with HCV infection with favorable efficacy [13,14]. Several clinical predictors of the sustained virologic response (SVR) to combination therapy have been elucidated, such as the viral factors (e.g. viral genotype 2 or 3, lower pretreatment viral load) and host factors (younger age, high body mass index, non-African–American or Asian races and host immune responses etc.) [13–18]. The Bureau of National Health Insurance in Taiwan has been reimbursing HCV treatment using a 24-week combination therapy for all CHC patients. The high SVR rates of combination therapy have been observed in either genotype 2/3-(up to 95.0%) or genotype 1b-infected patients (up to 73.5%) in Taiwan [19–21]. Whether insulin sensitivity plays a role in the response to combination therapy in Taiwanese CHC patients deserves further investigation. Since IR has been demonstrated to be associated with treatment responses to combination therapy among Caucasian CHC patients [22,23], the present study aimed to elucidate the impacts of IR on the efficacy of combination therapy with (PEG-IFN)/ribavirin in Taiwanese (Asian) patients without known type 2 DM history. With stratification of patients according to the major predictors for responses, the predictive role of IR and b-cell function assessed before combination therapy were evaluated.
2. Materials and methods 2.1. Patients and study design The present study was an open-label study in which 330 consecutive Taiwanese patients who had CHC and required therapy in the Kaohsiung Medical University Hospital were enrolled. All patients
713
were included if they were positive for HCV antibodies and serum HCV RNA. They received combination therapy with at least >80% of total (PEG-IFN) and total ribavirin doses and for at least 80% of the total duration of 24 weeks of therapy (80/80/80 adherence). An overnight (12-h) fasting blood sample was taken for analyses including fasting plasma glucose (FPG), alanine aminotransferase (ALT), and serum insulin levels and the virologic tests for HCV. The anthropometric data, which included body weight and height were measured, and a questionnaire regarding medical and drug history was also administered by research staff before treatment. Patients with the documented use of oral hypoglycemic medication or insulin for known type 2 DM; were positive for hepatitis B surface antigen (HBsAg); had human immunodeficiency virus type I infection; consumed alcohol more than 60 g/day or were intravenous drug abusers were excluded. All patients received liver biopsy before combination therapy with (PEG-IFN)/ ribavirin while liver histology was assessed blindly by one pathologist, showing chronic hepatitis of differing severity. Disease activity grade and fibrosis stage were quantitatively scored according to the histological activity index (HAI) [24,25] and the score of hepatic steatosis was assessed from zero (none) to three (severe) [26]. The study was approved by the Ethics Committee of the Kaohsiung Medical University Hospital and informed consent was obtained from each patient prior to enrollment.
2.2. Laboratory tests Serum HBsAg and third-generation HCV antibody (anti-HCV) were detected using a third-generation, commercially available enzyme-linked immunosorbent assay kit (AxSYM 3.0, Abbott Laboratories, Chicago, IL, USA). Alanine aminotransferase (ALT) was measured on a multichannel autoanalyzer. Fasting serum insulin levels were determined by radioimmunoassay (Diagnostic Products Co., Los Angeles, CA). The models of insulin resistance and insulin secretion were calculated on the basis of fasting values of plasma glucose and insulin, according to the homeostasis model assessment (HOMA) method that had been previously validated against clamp measurements [27]. Insulin resistance was determined by the homeostasis model assessment (HOMA-IR) according to the formula: HOMAIR = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/405 (>2.5 indicating a high index of IR [11]). Insulin secretion was calculated as the HOMA-b cell index according to the equation: HOMA%b = [fasting insulin (lU/mL) 360]/[fasting glucose (mg/dL)-63].
2.3. Detection/quantification of serum HCV RNA and genotyping Detection of serum HCV RNA was performed using a standardized automated qualitative RT-PCR assay (COBAS AMPLICOR Hepatitis C Virus Test, version 2.0; Roche, Branchburg, NJ, USA). The detection limit was 50 IU/mL. HCV genotypes 1a, 1b, 2a, 2b and 3a were determined by amplification of the core region using genotype-specific primers described by Okamoto et al. [28]. Pretreatment HCV RNA levels were determined using a branched DNA assay (Quantiplex HCV RNA 3.0, Bayer, Emeryville, CA), operated strictly in accordance with the manufacturer’s instructions. The quantification limit was 615 IU of HCV RNA per ml.
2.4. Regimen of and response to combination therapy Subjects were treated with combination therapy with either PEGIFN 2a 180 mcg/week (Pegasys, Roche, Basel, Switzerland) or PEGIFN 2b 80 mcg/week for weight 660 kg and 100 mcg/week for weight >60 kg (PEG-Intron, Schering-Plough Inc., Kenilworth, NJ) plus oral ribavirin 1000 mg/day for weight 675 kg and 1200 mg/day for weight >75 kg for 24 weeks. After cessation of therapy, subjects received follow-up for another 24 weeks. The presence of HCV RNA in the serum was assessed every three months to determine the responses to combination therapy. SVR was defined as clearance of serum HCV RNA at the end of the therapy and for 24 weeks after the cessation of therapy. All other patients were classified as nonresponders (NR).
714
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
2.5. Statistical analysis Frequency was compared between groups using the v2-test with Yates’ correction or Fisher’s exact test. Group means were compared using the Student t-test or Mann–Whitney U test. HOMA-IR, HOMA b-cell and HCV RNA levels and serum HCV RNA levels were expressed as means ± standard deviation after logarithmic transformation of original values to improve skewness before analyses. Multiple logistic regression was performed to assess the impact of genotypes and other variables on the odds of resistance to treatment. The procedures were performed using the SPSS 12.0 statistical package (SPSS Inc., Chicago, IL). All statistical analyses were based on two-sided hypothesis tests with a significance level of P < 0.05.
3. Results The baseline characteristics of the 330 patients are shown in Table 1. Of 330 patients with combination therapy, 258 [78.2%, 95% confidence interval (CI): 73.8–82.7%] patients achieved SVR. Comparison of factors between patients with SVR and NR is shown in Table 2. Patients with SVR had significantly lower frequency of genotype 1b infection, a lower pretreatment HCV RNA level, and a lower fibrosis score than those who were nonresponders (37.4% vs. 73.6%, 5.20 ± 1.06 Table 1 Baseline characteristics of 330 chronic hepatitis C patients without a known history of type 2 diabetes mellitus. Patients, n(%)
330
Age (years)* Male gender, n (%) Body mass index (kg/m2)* ALT (IU/L)* TG (mg/dL)* Cholesterol (mg/dL)* Histological activity index Total score* Fibrosis score* F0–2, n (%) F3–4, n (%) Steatosis score* 0/1/2/3 HCV genotype, n (%) 1b 2a 2b Mixed infection Unclassified HCV RNA levels (log IU/mL)* HOMA-IR3* >2.5 HOMA-%b*
49.7 ± 11.6 171 (51.8) 24.4 ± 3.23 145.7 ± 102.5 113.5 ± 69.1 172.2 ± 37.0 4.41 ± 2.33 1.31 ± 0.99 225 (86.1) 46 (13.9) 0.34 ± 0.57 230/86/13/1 150 (45.5) 108 (32.7) 19 (5.8) 42 (12.7) 11 (3.3) 5.21 ± 1.04 2.24 ± 2.46 96 (29.1%) 113.6 ± 169.2
Note: *Data presented as means ± standard deviation; DM, diabetes mellitus; ALT, alanine aminotransferase; Mixed infection, more than 2 genotypes identified in one patients; Unclassified, HCV genotypes (other than 1a, 1b, 2a, 2b and 3a) which can not be determined by the genotype-specific primers method were grouped as ‘‘unclassified genotype”; HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/ 405; HOMA-%b = [fasting insulin (lU/mL) 360]/[fasting glucose (mg/dL)-63].
vs. 5.31 ± 0.98 log IU/mL and 1.24 ± 0.97 vs. 1.54 ± 1.02, P < 0.001, P < 0.001 and P = 0.022, respectively). The mean HOMA-IR and frequency of HOMAIR >2.5 were significantly lower among patients with SVR than nonresponders (2.07 ± 2.23 vs. 2.88 ± 3.09, P = 0.015, and 25.6% vs. 41.7%, P = 0.008, respectively). Response to combination therapy was not associated with age, gender distribution, BMI, cholesterol, triglyceride and ALT levels, HOMA-%b, and steatosis. For 150 patients with genotype 1b infection, patients with SVR were significantly younger, had a significantly lower pretreatment HCV RNA level, a significantly lower frequency of HOMA-IR > 2.5 and a lower mean HOMA-IR than nonresponders (48.7 ± 11.4 vs. 52.7 ± 10.7 years, P = 0.036; 5.24 ± 1.03 vs. 5.76 ± 0.76 log IU/mL, P = 0.001; 22.7% vs. 41.5%, P = 0.015, 1.94 ± 2.07 vs. 2.71 ± 3.04, P = 0.069, respectively). Multivariate logistic regression analyses showed that the pretreatment HCV RNA level, HCV genotype and pretreatment HOMA-IR for all patients and HCV RNA level, pretreatment HOMA-IR and age for genotype 1b patients were independent factors associated with SVR (Table 3). The SVR rate among patients with high (>2.5) and low (62.5) HOMA-IR after stratification according to virologic factors is shown in Fig. 1. Of all 330 patients, patients with high HOMA-IR achieved significantly lower rate of SVR than those who with low IR (68.8%, CI: 59.5–78.1%, vs. 82.1%, CI: 77.2–87.1%, P = 0.008). The significantly lower SVR rate in high HOMA-IR patients than in low HOMA-IR patients was observed in 150 patients with genotype 1b-infection (50%, CI: 35.2–64.8%, vs. 70.8%, CI: 62.1–79.5%, P = 0.015) but not in the other 180 patients with genotype non-1b infection (84.6%, CI: 74.8–94.4% vs. 91.4%, CI: 86.5–96.3%, P = 0.179). Of the 127 patients with genotype 2 or 3 infection, the SVR rate was similar between patients with high and low HOMA-IR (85.7%, CI: 74.1–97.3%, 30/35, vs. 92.4%, CI: 87.0–97.8%, 85/92, P = 0.309). In 150 patients with genotype 1b infection, patients with a high baseline viral load (P400,000 IU/ml [29]) had a significantly lower SVR rate (55.3%, CI: 44.1– 66.5%, 42/76) than patients with a lower baseline viral load (<400,000 IU/ml) (74.3%, CI: 64.3–84.3%, 55/74) (P = 0.015). We further stratified genotype 1b patients by baseline viral loads. Among 76 genotype 1b patients with high baseline viral loads, patients with high HOMA-IR (>2.5) had a significantly lower SVR rate than those with low HOMA-IR (62.5) (30.8%, CI: 13.1–48.6%, 8/26 vs. 68.0%, CI: 55.1–80.9%, 34/50, P = 0.002). However, among 74 genotype 1b patients with lower baseline viral loads, the SVR rate did not differ between patients with high and low HOMA-IR (77.8%,CI: 58.6–97.0%, 14/18 vs. 73.2%, CI: 61.6– 84.8%, 41/56, P = 1.000). The SVR rates were also sim-
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
715
Table 2 Factors associated with response to combination therapy with pegylated interferon-alpha and ribavirin in chronic hepatitis C patients. Factors
All patients (N = 330) NR (N = 72)
SVR (N = 258)
Age Male gender, n (%) Body mass index (kg/m2)* ALT (IU/L)* TG (mg/dL)* Cholesterol (mg/dL)* HCV genotype 1b, n (%) HCV RNA levels (log IU/mL) Histological activity index Total score* Fibrosis score* F3–4, n (%) Steatosis score* 1–3, n (%) HOMA-IR* >2.5 HOMA-%b*
52.1 ± 12.1 33 (45.8) 24.8 ± 3.41 125.2 ± 84.3 111.5 ± 69.7 164.8 ± 38.6 53 (73.6) 5.75 ± 0.76 4.51 ± 2.30 1.54 ± 1.02 13 (18.1) 0.40 ± 0.60 25 (34.7) 2.89 ± 3.09 30 (41.7) 136.9 ± 241.4
*
P
HCV genotype 1b (N = 150)
P
NR (N = 53)
SVR (N = 97)
49.0 ± 11.3 138 (53.5) 24.3 ± 3.17 150.2 ± 106.6 114.1 ± 69.1 174.6 ± 36.3 97 (37.6) 5.06 ± 1.06
0.053 0.250 0.288 0.068 0.813 0.099 <0.001 <0.001
52.7 ± 10.7 26 (49.1) 24.7 ± 3.50 129.1 ± 93.4 112.4 ± 66.5 164.1 ± 38.0 – 5.76 ± 0.76
48.7 ± 11.4 49 (50.5) 23.9 ± 3.24 150.3 ± 115.2 102.6 ± 49.5 177.3 ± 37.9 – 5.24 ± 1.03
0.036 0.864 0.153 0.252 0.408 0.099 – 0.001
4.38 ± 2.34 1.25 ± 0.97 33 (12.8) 0.33 ± 0.56 75 (29.1) 2.07 ± 2.23 66 (25.6) 107.2 ± 142.7
0.674 0.026 0.254 0.362 0.317 0.015 0.008 0.246
4.45 ± 2.24 1.47 ± 1.05 9 (17.0) 0.36 ± 0.52 18 (44.0) 2.71 ± 3.04 22 (41.5) 136.9 ± 241.4
4.32 ± 2.12 1.31 ± 1.06 17 (17.5) 0.26 ± 0.51 21 (22.7) 1.94 ± 2.07 22 (22.7) 107.2 ± 142.7
0.726 0.371 0.933 0.251 0.222 0.069 0.015 0.246
Note: *Data presented as means ± standard deviation; DM, diabetes mellitus; ALT, alanine aminotransferase; HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/ 405; HOMA-%b = [fasting insulin (lU/mL) 360]/[fasting glucose (mg/dL)-63].
ilar between genotype 1b/high viral loads patients with low HOMA-IR (68.0%, CI: 55.1–80.9%, 34/50) and genotype 1b/lower viral loads patients with either high HOMA-IR (77.8%, CI: 58.6–97.0%, 14/18, P = 0.435) or low HOMA-IR (73.2%, CI: 61.6–84.8%, 41/56, P = 0.556). Genotype 1 patients with high viral loads have been classified as a ‘difficult-to-treat’ group [21,30]. Among these ‘difficult-to-treat’ patients, the mean HOMA-IR in 42 sustained responders was significantly lower than that of 34 non-responders (1.81 ± 1.46 vs. 3.40 ± 3.56, P = 0.014). Among 254 patients other than the ‘‘difficult-to-treat” group, the HOMA-IR was similar between sustained responders and non-responders (2.12 ± 2.35 vs. 2.42 ± 2.55, P = 0.429); the SVR rate also did not differ between patients with high and low HOMA-IR (82.9%, CI:
74.1–91.7%, 58/70 vs. 85.9%, CI: 80.9–90.9%, 158/184, P = 0.576).
4. Discussion In the present study, we enrolled the largest number of cases of Taiwanese (Asian) CHC patients, to our knowledge, and provided evidence that the baseline HOMA-IR had impact on the response to combination therapy with (PEG-IFN)/ribavirin. The association between higher HOMA-IR and poor response was observed and we particularly elucidated firstly the association among a specific group of ‘‘difficult-to-treat” patients who had genotype 1b infection and high pretreatment HCV RNA levels.
Table 3 Multivariate logistic regression analyses of variables associated with sustained viral response to combination therapy with pegylated interferon-alpha and ribavirin in chronic hepatitis C patients. Patients
Comparison
O.R.
95% C.I.
P value
For all patients (N = 330) HCV genotype HCV RNA level (log IU/mL) HOMA-IR
Variable
1b = 1, non-1b = 0 per 1-log increase per 1 increase
0.253 0.458 0.872
0.136–0.470 0.315–0.665 0.785–0.968
<0.001 <0.001 0.010
For HCV genotype 1b-infected patients (N = 150) HCV RNA level (log IU/mL) HOMA-IR Age
per 1-log increase per 1 increase per 1 years increase
0.511 0.851 0.964
0.329–0.792 0.731–0.992 0.032–0.997
0.003 0.039 0.033
Note: HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/ 405; O.R., odds ratio; C.I., confidence interval; HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/ mL)]/405.
716
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
HOMA-IR ≤ 2.5 SVR % 100 90
P=0.008*
HOMA-IR> 2.5
P=0.179 91.4
*Statistical significance
84.6
82.1
80
70.8
68.8
70
P=0.015*
60 50.0
50 40 30 20
192 234
66 96
117 128
44 52
75 106
22 44
10 0 ALL (N=330)
Genotype non 1b (N=180)
Genotype 1b (N=150)
Fig. 1. Sustained virological response rates to combination therapy with pegylated interferon-alpha and ribavirin among chronic hepatitis C patients in all 330 patients and among patients with HCV genotype 1b (150 patients) and non-1b (180 patients) infection. The HOMA-IR was defined as high (>2.5 black bars) and low (62.5 white bars). SVR, sustained virological response; HOMA, the homeostasis model assessment; IR, insulin resistance; HOMA-IR = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/405.
Glucose abnormality has been shown to be associated with chronic HCV infection. Type 2 DM in patients with chronic HCV infection is associated with worsening insulin sensitivity and an impaired first phase insulin response [6,31]. Our previous large-scale study conducted in southern Taiwan demonstrated an association between type 2 DM and virological status of HCV infection [32], so it is considered valuable to evaluate the impacts of IR in the clinical feature and its response to anti-HCV therapy. Our results revealed an association between HOMA-IR and response to combination therapy; not only implicating the crucial role of IR in the response to combination therapy but suggesting an importance to explore host factors related to treatment efficacy in the era of combination therapy for CHC as well. Combination therapy with (PEG-IFN)/ribavirin has been recommended as current standard of care for the treatment of chronic HCV infection [13,14]. The Bureau of National Health Insurance in Taiwan has been reimbursing HCV treatment using a 24-week combination therapy for CHC patients with all genotypes due to the favorable SVR rates. To evaluate the impact of insulin sensitivity on the response to combination therapy, we enrolled patients without known type 2 DM history in the present study and with 80/80/80 adherence for analyses to ameliorate the bias of inadequate therapeutic dose and duration. HCV genotype and HCV viral load remain the most important predictors for treatment response in combination therapy as per previous reports [13]. In contrast to HCV genotype 2 and 3 which was significantly more susceptible to combination therapy
with good response to standard or a shorter course of treatment [20,33], genotype 1-infected patients need more attention in developing more effective therapy and elucidating predictors for response which will be helpful for optimizing individualized regimens. Hence, the influence of the host factors on the SVR rate of anti-HCV therapy becomes more important among patients with unfavorable virological predictors. Romero-Gomez et al. have shown that IR, degree of fibrosis, and HCV genotype are independent predictors of the response to anti-HCV therapy in Spanish patients [22]. For patients with genotype 1, a significantly lower SVR rate was observed in patients with HOMAIR > 2 than patients with HOMA-IR 6 2 (32.8%, 23/ 70 vs. 60.5%, 26/43, P = 0.007]. Authors suggested HOMA-IR might assist in further refining the prediction of antiviral response in genotype 1 patients. We have found that high HOMA-IR impairs the response to combination therapy in Taiwanese patients. It is noteworthy in our study that the role of HOMA-IR on the response was observed in genotype 1 patients and particularly, for the first time, in those who were grouped as ‘difficult-to-treat’ patients (with genotype 1 infection and high HCV RNA level). With a poor response, the host factors might be important markers that are predictive of SVR in ‘difficult-to-treat’ patients. After adjusting for the viral load, we found patients with high IR had a lower SVR rate then did patients with low IR in HCV genotype 1-infected Taiwanese patients. These results suggested the possible value of evaluating IR to predict response in HCV genotype 1b infection and a high pretreatment serum HCV RNA level. Although the results were based on subset analysis and with the limitation of smaller sample sizes, the standard therapy for 24 weeks offered by the Bureau of National Health Insurance in Taiwan should be considered overcome by more effective therapies such as the longer period treatment of 48 weeks that has been shown to be more effective in our previous study in genotype 1 patients [21] when high HOMA-IR is depicted in these patients. Pretreatment measurement of HOMA-IR, in combination with tests of HCV genotypes and viral load, may be used as the determinants for selecting regimens in CHC patients. The report from Conjeevaram et al. showed the SVR rate of 49% and 36% in patients with genotype 1 infection with HOMA-IR 6 2 and >2, respectively, and authors concluded that IR was independently associated with a lower SVR rate [34]. It is noteworthy that the mean HOMA-IR of African and Caucasian Americans with different levels of steatosis was 3.5–6.8, which seemed higher than the 2.24 figure for our Taiwanese patients. In case IR does play a significant role on the response of anti-HCV therapy, the different status of IR between Taiwanese and American CHC patients may be one of the causes of the higher SVR rate in
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
our patients. On the other hand, to develop individualized (personalized) therapy for CHC, elucidating the changeable predictors of SVR and further manipulating them, seems potentially achievable in addition to adjusting the regimens according to the unchangeable viral factors such as HCV genotype. Since IR is considered as a factor that can be modified and improved by various interventions, further prospective studies will be valuable to evaluate whether the effective approaches to improve IR before initiation of the combination therapy for CHC can significantly increase the SVR rate. Poustchi et al. have reported that a significantly higher SVR rate was obtained in patients with a HOMA-IR < 2 (32/34, 94%) than in those with HOMA-IR > 2 (31/48, 65%) in 82 patients with genotypes 2 and 3 infection. Patients with HOMA-IR of <2 were 6.5 times more likely to achieve SVR than those with HOMA-IR > 2, and authors concluded accordingly that the high HOMA-IR is associated with a reduced response [23]. Nevertheless, similar SVR rates were observed among patients with low (91.4%) and high HOMA-IR (84.6%) in our genotype non-1b patients, as well as in the patients with genotype 2 or 3 (92.4% vs. 85.7%). Compared with reports by Poustchi et al. the SVR rate in Taiwanese patients with high HOMA-IR seemed to be higher (84.6% vs. 65%), which seems to account for a higher overall SVR rate in our study (90.6%) than that by Poustchi et al. (76.8%). Whether the better result of treatment for CHC in Taiwanese patients might minimize the impact of IR remains to be clarified. The discrepancies of the observation from different reports need further investigation. Around one- to two-thirds of liver biopsies from CHC patients have histological evidence of steatosis, which has been associated with being overweight, hepatic fibrosis and triglyceride levels [34–36]. There are also associations between IR, steatosis and liver fibrosis observed in CHC patient [36–40]. The report from Conjeevaram et al. has shown IR but not steatosis was independently associated with lower SVR rate [34]. D’Souza et al. has shown IR but not steatosis or fibrosis was independently associated with SVR rate [37]. In the present large-scale study, our results have demonstrated that IR but not steatosis or fibrosis was the most important predictor for response in addition to HCV genotype and viral load, particularly for the ‘‘difficult-to-treat patients”. IR has been suggested as the cause, rather than the consequence, of hepatic steatosis and fibrosis in patients with HCV, particularly those with genotype 1 infection [41]. The mechanisms for more obvious and important influence of IR rather than steatosis and fibrosis might need further study in the future. In conclusion, the present large-scale study in Taiwanese CHC patients showed that pretreatment HOMA-IR was associated with SVR to combination therapy with (PEG-IFN)/ribavirin, in particular among
717
‘‘difficult-to-treat” patients (genotype 1b and high baseline viral loads). These findings suggest clinical application of pretreatment HOMA-IR to predict the outcomes of combination therapy and determine the treatment regimens to maximize the efficacy based on the concept of individualized therapy. Since IR is a potentially modifiable factor, the responses to antiviral therapy for CHC may be improved by modulation of insulin signaling and improvements in IR and glucose control. The tremendous potential for evaluating novel therapies and targets including insulin-sensitizing drugs in CHC patients deserves prospective evaluation. Acknowledgement The authors thank the Taiwan Liver Research Foundation for secretarial and serum processing help. The foundation did not influence how the study was conducted or the way the manuscript was approved. References [1] Mazzaro C, Panarello G, Tesio F, Santini G, Crovatto M, Mazzi G, et al. Hepatitis C virus risk: a hepatitis C virus-related syndrome. J Intern Med 2000;247:535–545. [2] Hadziyannis SJ. The spectrum of extrahepatic manifestations in hepatitis C virus infection. J Viral Hepat 1997;4:9–28. [3] Huang JF, Chuang WL, Dai CY, Ho CK, Hwang SJ, Chen SC, et al. Viral hepatitis and proteinuria in an area endemic for hepatitis B and C infections: Another chain of link? J Intern Med 2006;260:255–262. [4] Simo R, Hernandez C, Genesca J, Jardi R, Mesa J. High prevalence of hepatitis C virus infection in diabetic patients. Diabetes Care 1996;19:998–1000. [5] Mason AL, Lau JY, Hoang N, Qian K, Alexander GJ, Xu L, et al. Association of diabetes mellitus and chronic hepatitis C virus infection. Hepatology 1999;29:328–333. [6] Knobler H, Schihmanter R, Zifroni A, Fenakel G, Schattner A. Increased risk of type 2 diabetes in non-cirrhotic patients with chronic hepatitis C virus infection. Mayo Clin Proc 2000;75:355–359. [7] Dai CY, Chuang WL, Ho CK, Hsieh MY, Huang JF, Lee LP, et al. Associations between hepatitis C viremia and low serum triglyceride and cholesterol levels: a community-based study. J Hepatol 2008;49:9–16. [8] Petrides AS. Liver disease and diabetes mellitus. Diabetes Rev 1994;2:2–18. [9] Petit JM, Bour JB, Galland-Jos C, Minello A, Verges B, Guiguet M, et al. Risk factors for diabetes mellitus and early insulin resistance in chronic hepatitis C. J Hepatol 2001;35:279–283. [10] Hui JM, Sud A, Farrell GC, Bandara P, Byth K, Kench JG, et al. Insulin resistance is associated with chronic hepatitis C virus infection and fibrosis progression. Gastroenterology 2003;125:1695–1704. [11] Taura N, Ichikawa T, Hamasaki K, Nakao K, Nishimura D, Goto T, et al. Association between liver fibrosis and insulin sensitivity in chronic hepatitis C patients. Am J Gastroenterol 2006;101:2752–2759. [12] Svegliati-Baroni G, Bugianesi E, Bouserhal T, Marini F, Ridolfi F, Tarsetti F, et al. Post-load insulin resistance is an independent predictor of hepatic fibrosis in virus C chronic hepatitis and in nonalcoholic fatty liver disease. Gut 2007;56:1296–1301.
718
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
[13] Strader DB, Wright T, Thomas DL, Seeff LB. American Association for the Study of Liver Diseases. Diagnosis, management, and treatment of hepatitis C. Hepatology 2004;39: 1147–1171. [14] Fried MW, Shiffman ML, Reddy KR, Smith C, Marinos G, Goncales FL, et al. Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection. N Engl J Med 2002;347:975–982. [15] Sterling RK, Hofmann CM, Luketic VA, Sanyal AJ, Contos MJ, Mills AS, et al. Treatment of chronic hepatitis C virus in the Virginia department of corrections: Can compliance overcome racial differences to response? Am J Gastroenterol 2004;99:866–872. [16] Bressler BL, Guindi M, Tomlinson G, Heathcote J. High body mass index is an independent risk factor for nonresponse to antiviral treatment in chronic hepatitis C. Hepatology 2003;38:639–644. [17] Muir AJ, Bornstein JD, Killenberg PG. Peginterferon alfa-2b and ribavirin for the treatment of chronic hepatitis C in blacks and non-Hispanic whites. N Engl J Med 2004;350:2265–2271. [18] Hadziyannis SJ, Sette Jr H, Morgan TR, Balan V, Diago M, Marcellin P, et al. Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose. Ann Intern Med 2004;140:346–355. [19] Lee SD, Yu ML, Cheng PN, Lai MY, Chao YC, Hwang SJ, et al. Comparison of a 6-month course peginterferon alpha-2b plus ribavirin and interferon alpha-2b plus ribavirin in treating Chinese patients with chronic hepatitis C in Taiwan. J Viral Hepat 2005;12:283–291. [20] Yu ML, Dai CY, Huang JF, Hou NJ, Lee LP, Hsieh MY, et al. A randomized study of peginterferon and ribavirin for 16 vs 24 weeks in patients with genotype 2 chronic hepatitis C. Gut 2007;56:553–559. [21] Yu ML, Dai CY, Huang JF, Chiu CF, Yang YH, Hou NJ, et al. Rapid virological response and treatment duration for chronic hepatitis C genotype 1 patients: A randomized trial. Hepatology 2008;47:1884–1893. [22] Romero-Gomez M, Del Mar Viloria M, Andrade RJ, Salmeron J, Diago M, Fernandez-Rodriguez CM, et al. Insulin resistance impairs sustained response rate to peginterferon plus ribavirin in chronic hepatitis C patients. Gastroenterology 2005;128:636–641. [23] Poustchi H, Negro F, Hui J, Cua IH, Brandt LR, Kench JG, et al. Insulin resistance and response to therapy in patients infected with chronic hepatitis C virus genotypes 2 and 3. J Hepatol 2008;48:28–34. [24] Knodell RG, Ishak KG, Black WC, Chen TS, Craig R, Kaplowitz N, et al. Formulation and application of a numerical scoring system for assessing histological activity in asymptomatic chronic active hepatitis. Hepatology 1982;1:431–435. [25] Scheuer PJ. Classification of chronic viral hepatitis: a need for reassessment. J Hepatol 1991;13:372–374. [26] Kleiner DE, Brunt EM, Van Natta M, Behling C, Contos MJ, Cummings OW, et al. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology 2005;41:1313–1321.
[27] Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentration in man. Diabetologia 1985;28:412–429. [28] Okamoto H, Tokita H, Sakamoto M, Horikita M, Kojima M, Iizuka H, et al. Characterization of the genomic sequence of type V (or 3a) hepatitis C virus isolates and PCR primers for specific detection. J Gen Virol 1993;74:2385–2390. [29] Pacific Association for the Study of the Liver (APASL) Hepatitis C Working Party McCaughan GW, Omata M, Amarapurkar D, et al. Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection. J Gastroenterol Hepatol 2007;22:615–633. [30] Dai CY, Chuang WL, Chang WY, Chen SC, Lee LP, Hsieh MY, et al. Tumor necrosis factor alpha promoter polymorphism at position –308 predicts hepatitis C virus response to combination therapy. J Infect Dis 2006;193:98–101. [31] Labropoulou-Karatza C, Goritsas C, Fragopanagou H, Repandi M, Matsouka P, Alexandrides T. High prevalence of diabetes mellitus among adult b-thalassemic patients with chronic hepatitis C. Eur J Gastroenterol Hepatol 1999;11:1033–1036. [32] Huang JF, Dai CY, Hwang SJ, Ho CK, Hsiao PJ, Hsieh MY, et al. Hepatitis C viremia increases the association with type 2 diabetes mellitus in a hepatitis B and C endemic area: an epidemiological link with virological implication. Am J Gastroenterol 2007;102:1237–1243. [33] Mangia A, Santoro R, Minerva N, Ricci GL, Carretta V, Persico M, et al. Peginterferon alfa-2b and ribavirin for 12 vs. 24 weeks in HCV genotype 2 or 3. N Engl J Med 2005;352:2609–2617. [34] Conjeevaram HS, Kleiner DE, Everhart JE, Hoofnagle JH, Zacks S, Afdhal NH, et al. Race, insulin resistance and hepatic steatosis in chronic hepatitis C. Hepatology 2007;45:80–87. [35] Powell EE, Jonsson JR, Clouston AD. Steatosis: co-factor in other liver diseases. Hepatology 2005;42:5–13. [36] Hsieh MH, Lee LP, Hsieh MY, Tsai KB, Huang JF, Hou NJ, et al. Hepatic steatosis and fibrosis in chronic hepatitis C in Taiwan. Jpn J Infect Dis 2007;60:377–381. [37] D’Souza R, Sabin CA, Foster GR. Insulin resistance plays a significant role in liver fibrosis in chronic hepatitis C and in the response to antiviral therapy. Am J Gastroenterol 2005;100:1509–1515. [38] Muzzi A, Leandro G, Rubbia-Brandt L, James R, Keiser O, Malinverni R, et al. Insulin resistance is associated with liver fibrosis in non-diabetic chronic hepatitis C patients. J Hepatol 2005;42:41–46. [39] Sud A, Hui JM, Farrell GC, Bandara P, Kench JG, Fung C, et al. Improved prediction of fibrosis in chronic hepatitis C using measures of insulin resistance in a probability index. Hepatology 2004;39:1239–1247. [40] Zekry A, McHutchison JG, Diehl AM. Insulin resistance and steatosis in hepatitis C virus infection. Gut 2005;54:903–906. [41] Fartoux L, Poujol-Robert A, Gue’chot J, Wendum D, Poupon R, Serfaty L. Insulin resistance is a cause of steatosis and fibrosis progression in chronic hepatitis C. Gut 2005;54:1003–1008.
Insulin resistance predicts response to peginterferonalpha/ribavirin combination therapy in chronic hepatitis C patientsq Chia-Yen Dai1,2,3, Jee-Fu Huang1,4, Ming-Yen Hsieh1, Nai-Jen Hou1,4, Zu-Yau Lin1,2, Shinn-Chern Chen1,2, Ming-Yuh Hsieh1,2, Liang-Yen Wang1,2, Wen-Yu Chang1,2, Wan-Long Chuang1,2,*, , Ming-Lung Yu1,2,3, 1
Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, No. 100, Tzyou 1st Rd, Kaohsiung 807, Taiwan 2 Faculty of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 3 Department of Occupational and Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 4 Department of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
See Editorial, pages 648–651
Background/Aims: Insulin resistance (IR) might be associated with hepatitis C virus (HCV) infection. This study aimed to elucidate impact of IR and beta-cell function on the response to peginterferon-alpha (PEG-IFN)/ribavirin combination therapy in chronic hepatitis C (CHC) patients. Methods: Three hundred and thirty patients without overt diabetes were treated with combination therapy with (PEG-IFN)/ribavirin for 24 weeks. The IR and beta-cell function were evaluated by homeostasis model assessment of IR (HOMA-IR) and homeostasis model assessment of beta-cell function (HOMA-beta) before treatment. Results: HCV genotype, pretreatment HCV RNA level and pretreatment HOMA-IR, but not HOMA-beta, were independent factors associated with sustained virologic response (SVR). In 150 patients with genotype 1b infection, pretreatment HCV RNA level, HOMA-IR and age were independent predictors for SVR. The significantly lower SVR rate in high HOMA-IR patients was observed in 76 patients with high HCV RNA levels (P400,000 IU/mL) who were defined as ‘difficult-to-treat’ patients. The mean HOMA-IR of ‘difficult-to-treat’ patients was significantly lower in 42 sustained responders than in 34 non-responders. Conclusions: IR was associated with SVR to (PEG-IFN)/ribavirin therapy for CHC, especially among ‘difficult-to-treat’ patients. These findings suggested clinical application of pretreatment HOMA-IR could enable treatment outcome to be predicted and treatment regimens to be determined. Ó 2009 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. Keywords: Chronic hepatitis C; Combination therapy; Genotype; Insulin resistance; The homeostasis assessment model
Received 27 July 2008; received in revised form 4 December 2008; accepted 9 December 2008; available online 6 February 2009 Associate Editor: F. Negro q The authors who have taken part in the research of this paper declared that they do not have a relationship with the manufacturers of the drugs involved either in the past or present and they did not receive funding from the manufacturers to carry out their research. * Corresponding author. Tel.: +886 7 3121101x7475; fax: +886-7-3234553. E-mail address: fi[email protected] (W.-L. Chuang). These authors contributed equally to this work. Abbreviations: ALT, alanine aminotransferase; anti-HCV, HCV antibody; FPG, fasting plasma glucose; BMI, body mass index; CHC, chronic hepatitis; HBsAg, hepatitis B surface antigen; SVR, sustained virologic response; HOMA, homeostasis model assessment; IR, insulin resistance; DM, diabetes mellitus; HAI, histological activity index 0168-8278/$36.00 Ó 2009 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.jhep.2008.12.017
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
1. Introduction Hepatitis C virus (HCV) has hepatotropic and lymphotropic characteristics leading to a wide spectrum of extrahepatic manifestations [1,2]. The association between a higher prevalence of type 2 diabetes mellitus (DM), with multifactorial pathogenetic mechanisms, and HCV infection has been reported [3–7]. In development of glucose abnormalities, insulin resistance (IR) and alteration of b-cell function have an important role. IR, caused by many metabolic factors, is also a common feature of disturbed carbohydrate metabolism in liver disease with or without cirrhosis, and precedes the development of type 2 DM [8,9]. The associations between IR and the clinical features of chronic hepatitis C (CHC) have been observed. Hui et al. [10] reported that HCV may induce IR irrespective of the severity of liver disease and IR may be associated with severe hepatic fibrosis and contribute to fibrotic progression in chronic HCV infection, as shown in other studies [10–12]. Combination therapy with peginterferon-alpha (PEG-IFN)/ribavirin has been recommended as standard therapy for patients with HCV infection with favorable efficacy [13,14]. Several clinical predictors of the sustained virologic response (SVR) to combination therapy have been elucidated, such as the viral factors (e.g. viral genotype 2 or 3, lower pretreatment viral load) and host factors (younger age, high body mass index, non-African–American or Asian races and host immune responses etc.) [13–18]. The Bureau of National Health Insurance in Taiwan has been reimbursing HCV treatment using a 24-week combination therapy for all CHC patients. The high SVR rates of combination therapy have been observed in either genotype 2/3-(up to 95.0%) or genotype 1b-infected patients (up to 73.5%) in Taiwan [19–21]. Whether insulin sensitivity plays a role in the response to combination therapy in Taiwanese CHC patients deserves further investigation. Since IR has been demonstrated to be associated with treatment responses to combination therapy among Caucasian CHC patients [22,23], the present study aimed to elucidate the impacts of IR on the efficacy of combination therapy with (PEG-IFN)/ribavirin in Taiwanese (Asian) patients without known type 2 DM history. With stratification of patients according to the major predictors for responses, the predictive role of IR and b-cell function assessed before combination therapy were evaluated.
2. Materials and methods 2.1. Patients and study design The present study was an open-label study in which 330 consecutive Taiwanese patients who had CHC and required therapy in the Kaohsiung Medical University Hospital were enrolled. All patients
713
were included if they were positive for HCV antibodies and serum HCV RNA. They received combination therapy with at least >80% of total (PEG-IFN) and total ribavirin doses and for at least 80% of the total duration of 24 weeks of therapy (80/80/80 adherence). An overnight (12-h) fasting blood sample was taken for analyses including fasting plasma glucose (FPG), alanine aminotransferase (ALT), and serum insulin levels and the virologic tests for HCV. The anthropometric data, which included body weight and height were measured, and a questionnaire regarding medical and drug history was also administered by research staff before treatment. Patients with the documented use of oral hypoglycemic medication or insulin for known type 2 DM; were positive for hepatitis B surface antigen (HBsAg); had human immunodeficiency virus type I infection; consumed alcohol more than 60 g/day or were intravenous drug abusers were excluded. All patients received liver biopsy before combination therapy with (PEG-IFN)/ ribavirin while liver histology was assessed blindly by one pathologist, showing chronic hepatitis of differing severity. Disease activity grade and fibrosis stage were quantitatively scored according to the histological activity index (HAI) [24,25] and the score of hepatic steatosis was assessed from zero (none) to three (severe) [26]. The study was approved by the Ethics Committee of the Kaohsiung Medical University Hospital and informed consent was obtained from each patient prior to enrollment.
2.2. Laboratory tests Serum HBsAg and third-generation HCV antibody (anti-HCV) were detected using a third-generation, commercially available enzyme-linked immunosorbent assay kit (AxSYM 3.0, Abbott Laboratories, Chicago, IL, USA). Alanine aminotransferase (ALT) was measured on a multichannel autoanalyzer. Fasting serum insulin levels were determined by radioimmunoassay (Diagnostic Products Co., Los Angeles, CA). The models of insulin resistance and insulin secretion were calculated on the basis of fasting values of plasma glucose and insulin, according to the homeostasis model assessment (HOMA) method that had been previously validated against clamp measurements [27]. Insulin resistance was determined by the homeostasis model assessment (HOMA-IR) according to the formula: HOMAIR = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/405 (>2.5 indicating a high index of IR [11]). Insulin secretion was calculated as the HOMA-b cell index according to the equation: HOMA%b = [fasting insulin (lU/mL) 360]/[fasting glucose (mg/dL)-63].
2.3. Detection/quantification of serum HCV RNA and genotyping Detection of serum HCV RNA was performed using a standardized automated qualitative RT-PCR assay (COBAS AMPLICOR Hepatitis C Virus Test, version 2.0; Roche, Branchburg, NJ, USA). The detection limit was 50 IU/mL. HCV genotypes 1a, 1b, 2a, 2b and 3a were determined by amplification of the core region using genotype-specific primers described by Okamoto et al. [28]. Pretreatment HCV RNA levels were determined using a branched DNA assay (Quantiplex HCV RNA 3.0, Bayer, Emeryville, CA), operated strictly in accordance with the manufacturer’s instructions. The quantification limit was 615 IU of HCV RNA per ml.
2.4. Regimen of and response to combination therapy Subjects were treated with combination therapy with either PEGIFN 2a 180 mcg/week (Pegasys, Roche, Basel, Switzerland) or PEGIFN 2b 80 mcg/week for weight 660 kg and 100 mcg/week for weight >60 kg (PEG-Intron, Schering-Plough Inc., Kenilworth, NJ) plus oral ribavirin 1000 mg/day for weight 675 kg and 1200 mg/day for weight >75 kg for 24 weeks. After cessation of therapy, subjects received follow-up for another 24 weeks. The presence of HCV RNA in the serum was assessed every three months to determine the responses to combination therapy. SVR was defined as clearance of serum HCV RNA at the end of the therapy and for 24 weeks after the cessation of therapy. All other patients were classified as nonresponders (NR).
714
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
2.5. Statistical analysis Frequency was compared between groups using the v2-test with Yates’ correction or Fisher’s exact test. Group means were compared using the Student t-test or Mann–Whitney U test. HOMA-IR, HOMA b-cell and HCV RNA levels and serum HCV RNA levels were expressed as means ± standard deviation after logarithmic transformation of original values to improve skewness before analyses. Multiple logistic regression was performed to assess the impact of genotypes and other variables on the odds of resistance to treatment. The procedures were performed using the SPSS 12.0 statistical package (SPSS Inc., Chicago, IL). All statistical analyses were based on two-sided hypothesis tests with a significance level of P < 0.05.
3. Results The baseline characteristics of the 330 patients are shown in Table 1. Of 330 patients with combination therapy, 258 [78.2%, 95% confidence interval (CI): 73.8–82.7%] patients achieved SVR. Comparison of factors between patients with SVR and NR is shown in Table 2. Patients with SVR had significantly lower frequency of genotype 1b infection, a lower pretreatment HCV RNA level, and a lower fibrosis score than those who were nonresponders (37.4% vs. 73.6%, 5.20 ± 1.06 Table 1 Baseline characteristics of 330 chronic hepatitis C patients without a known history of type 2 diabetes mellitus. Patients, n(%)
330
Age (years)* Male gender, n (%) Body mass index (kg/m2)* ALT (IU/L)* TG (mg/dL)* Cholesterol (mg/dL)* Histological activity index Total score* Fibrosis score* F0–2, n (%) F3–4, n (%) Steatosis score* 0/1/2/3 HCV genotype, n (%) 1b 2a 2b Mixed infection Unclassified HCV RNA levels (log IU/mL)* HOMA-IR3* >2.5 HOMA-%b*
49.7 ± 11.6 171 (51.8) 24.4 ± 3.23 145.7 ± 102.5 113.5 ± 69.1 172.2 ± 37.0 4.41 ± 2.33 1.31 ± 0.99 225 (86.1) 46 (13.9) 0.34 ± 0.57 230/86/13/1 150 (45.5) 108 (32.7) 19 (5.8) 42 (12.7) 11 (3.3) 5.21 ± 1.04 2.24 ± 2.46 96 (29.1%) 113.6 ± 169.2
Note: *Data presented as means ± standard deviation; DM, diabetes mellitus; ALT, alanine aminotransferase; Mixed infection, more than 2 genotypes identified in one patients; Unclassified, HCV genotypes (other than 1a, 1b, 2a, 2b and 3a) which can not be determined by the genotype-specific primers method were grouped as ‘‘unclassified genotype”; HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/ 405; HOMA-%b = [fasting insulin (lU/mL) 360]/[fasting glucose (mg/dL)-63].
vs. 5.31 ± 0.98 log IU/mL and 1.24 ± 0.97 vs. 1.54 ± 1.02, P < 0.001, P < 0.001 and P = 0.022, respectively). The mean HOMA-IR and frequency of HOMAIR >2.5 were significantly lower among patients with SVR than nonresponders (2.07 ± 2.23 vs. 2.88 ± 3.09, P = 0.015, and 25.6% vs. 41.7%, P = 0.008, respectively). Response to combination therapy was not associated with age, gender distribution, BMI, cholesterol, triglyceride and ALT levels, HOMA-%b, and steatosis. For 150 patients with genotype 1b infection, patients with SVR were significantly younger, had a significantly lower pretreatment HCV RNA level, a significantly lower frequency of HOMA-IR > 2.5 and a lower mean HOMA-IR than nonresponders (48.7 ± 11.4 vs. 52.7 ± 10.7 years, P = 0.036; 5.24 ± 1.03 vs. 5.76 ± 0.76 log IU/mL, P = 0.001; 22.7% vs. 41.5%, P = 0.015, 1.94 ± 2.07 vs. 2.71 ± 3.04, P = 0.069, respectively). Multivariate logistic regression analyses showed that the pretreatment HCV RNA level, HCV genotype and pretreatment HOMA-IR for all patients and HCV RNA level, pretreatment HOMA-IR and age for genotype 1b patients were independent factors associated with SVR (Table 3). The SVR rate among patients with high (>2.5) and low (62.5) HOMA-IR after stratification according to virologic factors is shown in Fig. 1. Of all 330 patients, patients with high HOMA-IR achieved significantly lower rate of SVR than those who with low IR (68.8%, CI: 59.5–78.1%, vs. 82.1%, CI: 77.2–87.1%, P = 0.008). The significantly lower SVR rate in high HOMA-IR patients than in low HOMA-IR patients was observed in 150 patients with genotype 1b-infection (50%, CI: 35.2–64.8%, vs. 70.8%, CI: 62.1–79.5%, P = 0.015) but not in the other 180 patients with genotype non-1b infection (84.6%, CI: 74.8–94.4% vs. 91.4%, CI: 86.5–96.3%, P = 0.179). Of the 127 patients with genotype 2 or 3 infection, the SVR rate was similar between patients with high and low HOMA-IR (85.7%, CI: 74.1–97.3%, 30/35, vs. 92.4%, CI: 87.0–97.8%, 85/92, P = 0.309). In 150 patients with genotype 1b infection, patients with a high baseline viral load (P400,000 IU/ml [29]) had a significantly lower SVR rate (55.3%, CI: 44.1– 66.5%, 42/76) than patients with a lower baseline viral load (<400,000 IU/ml) (74.3%, CI: 64.3–84.3%, 55/74) (P = 0.015). We further stratified genotype 1b patients by baseline viral loads. Among 76 genotype 1b patients with high baseline viral loads, patients with high HOMA-IR (>2.5) had a significantly lower SVR rate than those with low HOMA-IR (62.5) (30.8%, CI: 13.1–48.6%, 8/26 vs. 68.0%, CI: 55.1–80.9%, 34/50, P = 0.002). However, among 74 genotype 1b patients with lower baseline viral loads, the SVR rate did not differ between patients with high and low HOMA-IR (77.8%,CI: 58.6–97.0%, 14/18 vs. 73.2%, CI: 61.6– 84.8%, 41/56, P = 1.000). The SVR rates were also sim-
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
715
Table 2 Factors associated with response to combination therapy with pegylated interferon-alpha and ribavirin in chronic hepatitis C patients. Factors
All patients (N = 330) NR (N = 72)
SVR (N = 258)
Age Male gender, n (%) Body mass index (kg/m2)* ALT (IU/L)* TG (mg/dL)* Cholesterol (mg/dL)* HCV genotype 1b, n (%) HCV RNA levels (log IU/mL) Histological activity index Total score* Fibrosis score* F3–4, n (%) Steatosis score* 1–3, n (%) HOMA-IR* >2.5 HOMA-%b*
52.1 ± 12.1 33 (45.8) 24.8 ± 3.41 125.2 ± 84.3 111.5 ± 69.7 164.8 ± 38.6 53 (73.6) 5.75 ± 0.76 4.51 ± 2.30 1.54 ± 1.02 13 (18.1) 0.40 ± 0.60 25 (34.7) 2.89 ± 3.09 30 (41.7) 136.9 ± 241.4
*
P
HCV genotype 1b (N = 150)
P
NR (N = 53)
SVR (N = 97)
49.0 ± 11.3 138 (53.5) 24.3 ± 3.17 150.2 ± 106.6 114.1 ± 69.1 174.6 ± 36.3 97 (37.6) 5.06 ± 1.06
0.053 0.250 0.288 0.068 0.813 0.099 <0.001 <0.001
52.7 ± 10.7 26 (49.1) 24.7 ± 3.50 129.1 ± 93.4 112.4 ± 66.5 164.1 ± 38.0 – 5.76 ± 0.76
48.7 ± 11.4 49 (50.5) 23.9 ± 3.24 150.3 ± 115.2 102.6 ± 49.5 177.3 ± 37.9 – 5.24 ± 1.03
0.036 0.864 0.153 0.252 0.408 0.099 – 0.001
4.38 ± 2.34 1.25 ± 0.97 33 (12.8) 0.33 ± 0.56 75 (29.1) 2.07 ± 2.23 66 (25.6) 107.2 ± 142.7
0.674 0.026 0.254 0.362 0.317 0.015 0.008 0.246
4.45 ± 2.24 1.47 ± 1.05 9 (17.0) 0.36 ± 0.52 18 (44.0) 2.71 ± 3.04 22 (41.5) 136.9 ± 241.4
4.32 ± 2.12 1.31 ± 1.06 17 (17.5) 0.26 ± 0.51 21 (22.7) 1.94 ± 2.07 22 (22.7) 107.2 ± 142.7
0.726 0.371 0.933 0.251 0.222 0.069 0.015 0.246
Note: *Data presented as means ± standard deviation; DM, diabetes mellitus; ALT, alanine aminotransferase; HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/ 405; HOMA-%b = [fasting insulin (lU/mL) 360]/[fasting glucose (mg/dL)-63].
ilar between genotype 1b/high viral loads patients with low HOMA-IR (68.0%, CI: 55.1–80.9%, 34/50) and genotype 1b/lower viral loads patients with either high HOMA-IR (77.8%, CI: 58.6–97.0%, 14/18, P = 0.435) or low HOMA-IR (73.2%, CI: 61.6–84.8%, 41/56, P = 0.556). Genotype 1 patients with high viral loads have been classified as a ‘difficult-to-treat’ group [21,30]. Among these ‘difficult-to-treat’ patients, the mean HOMA-IR in 42 sustained responders was significantly lower than that of 34 non-responders (1.81 ± 1.46 vs. 3.40 ± 3.56, P = 0.014). Among 254 patients other than the ‘‘difficult-to-treat” group, the HOMA-IR was similar between sustained responders and non-responders (2.12 ± 2.35 vs. 2.42 ± 2.55, P = 0.429); the SVR rate also did not differ between patients with high and low HOMA-IR (82.9%, CI:
74.1–91.7%, 58/70 vs. 85.9%, CI: 80.9–90.9%, 158/184, P = 0.576).
4. Discussion In the present study, we enrolled the largest number of cases of Taiwanese (Asian) CHC patients, to our knowledge, and provided evidence that the baseline HOMA-IR had impact on the response to combination therapy with (PEG-IFN)/ribavirin. The association between higher HOMA-IR and poor response was observed and we particularly elucidated firstly the association among a specific group of ‘‘difficult-to-treat” patients who had genotype 1b infection and high pretreatment HCV RNA levels.
Table 3 Multivariate logistic regression analyses of variables associated with sustained viral response to combination therapy with pegylated interferon-alpha and ribavirin in chronic hepatitis C patients. Patients
Comparison
O.R.
95% C.I.
P value
For all patients (N = 330) HCV genotype HCV RNA level (log IU/mL) HOMA-IR
Variable
1b = 1, non-1b = 0 per 1-log increase per 1 increase
0.253 0.458 0.872
0.136–0.470 0.315–0.665 0.785–0.968
<0.001 <0.001 0.010
For HCV genotype 1b-infected patients (N = 150) HCV RNA level (log IU/mL) HOMA-IR Age
per 1-log increase per 1 increase per 1 years increase
0.511 0.851 0.964
0.329–0.792 0.731–0.992 0.032–0.997
0.003 0.039 0.033
Note: HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/ 405; O.R., odds ratio; C.I., confidence interval; HOMA-IR (homeostasis model assessment of insulin resistance) = [fasting glucose (mg/dL) fasting insulin (lU/ mL)]/405.
716
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
HOMA-IR ≤ 2.5 SVR % 100 90
P=0.008*
HOMA-IR> 2.5
P=0.179 91.4
*Statistical significance
84.6
82.1
80
70.8
68.8
70
P=0.015*
60 50.0
50 40 30 20
192 234
66 96
117 128
44 52
75 106
22 44
10 0 ALL (N=330)
Genotype non 1b (N=180)
Genotype 1b (N=150)
Fig. 1. Sustained virological response rates to combination therapy with pegylated interferon-alpha and ribavirin among chronic hepatitis C patients in all 330 patients and among patients with HCV genotype 1b (150 patients) and non-1b (180 patients) infection. The HOMA-IR was defined as high (>2.5 black bars) and low (62.5 white bars). SVR, sustained virological response; HOMA, the homeostasis model assessment; IR, insulin resistance; HOMA-IR = [fasting glucose (mg/dL) fasting insulin (lU/mL)]/405.
Glucose abnormality has been shown to be associated with chronic HCV infection. Type 2 DM in patients with chronic HCV infection is associated with worsening insulin sensitivity and an impaired first phase insulin response [6,31]. Our previous large-scale study conducted in southern Taiwan demonstrated an association between type 2 DM and virological status of HCV infection [32], so it is considered valuable to evaluate the impacts of IR in the clinical feature and its response to anti-HCV therapy. Our results revealed an association between HOMA-IR and response to combination therapy; not only implicating the crucial role of IR in the response to combination therapy but suggesting an importance to explore host factors related to treatment efficacy in the era of combination therapy for CHC as well. Combination therapy with (PEG-IFN)/ribavirin has been recommended as current standard of care for the treatment of chronic HCV infection [13,14]. The Bureau of National Health Insurance in Taiwan has been reimbursing HCV treatment using a 24-week combination therapy for CHC patients with all genotypes due to the favorable SVR rates. To evaluate the impact of insulin sensitivity on the response to combination therapy, we enrolled patients without known type 2 DM history in the present study and with 80/80/80 adherence for analyses to ameliorate the bias of inadequate therapeutic dose and duration. HCV genotype and HCV viral load remain the most important predictors for treatment response in combination therapy as per previous reports [13]. In contrast to HCV genotype 2 and 3 which was significantly more susceptible to combination therapy
with good response to standard or a shorter course of treatment [20,33], genotype 1-infected patients need more attention in developing more effective therapy and elucidating predictors for response which will be helpful for optimizing individualized regimens. Hence, the influence of the host factors on the SVR rate of anti-HCV therapy becomes more important among patients with unfavorable virological predictors. Romero-Gomez et al. have shown that IR, degree of fibrosis, and HCV genotype are independent predictors of the response to anti-HCV therapy in Spanish patients [22]. For patients with genotype 1, a significantly lower SVR rate was observed in patients with HOMAIR > 2 than patients with HOMA-IR 6 2 (32.8%, 23/ 70 vs. 60.5%, 26/43, P = 0.007]. Authors suggested HOMA-IR might assist in further refining the prediction of antiviral response in genotype 1 patients. We have found that high HOMA-IR impairs the response to combination therapy in Taiwanese patients. It is noteworthy in our study that the role of HOMA-IR on the response was observed in genotype 1 patients and particularly, for the first time, in those who were grouped as ‘difficult-to-treat’ patients (with genotype 1 infection and high HCV RNA level). With a poor response, the host factors might be important markers that are predictive of SVR in ‘difficult-to-treat’ patients. After adjusting for the viral load, we found patients with high IR had a lower SVR rate then did patients with low IR in HCV genotype 1-infected Taiwanese patients. These results suggested the possible value of evaluating IR to predict response in HCV genotype 1b infection and a high pretreatment serum HCV RNA level. Although the results were based on subset analysis and with the limitation of smaller sample sizes, the standard therapy for 24 weeks offered by the Bureau of National Health Insurance in Taiwan should be considered overcome by more effective therapies such as the longer period treatment of 48 weeks that has been shown to be more effective in our previous study in genotype 1 patients [21] when high HOMA-IR is depicted in these patients. Pretreatment measurement of HOMA-IR, in combination with tests of HCV genotypes and viral load, may be used as the determinants for selecting regimens in CHC patients. The report from Conjeevaram et al. showed the SVR rate of 49% and 36% in patients with genotype 1 infection with HOMA-IR 6 2 and >2, respectively, and authors concluded that IR was independently associated with a lower SVR rate [34]. It is noteworthy that the mean HOMA-IR of African and Caucasian Americans with different levels of steatosis was 3.5–6.8, which seemed higher than the 2.24 figure for our Taiwanese patients. In case IR does play a significant role on the response of anti-HCV therapy, the different status of IR between Taiwanese and American CHC patients may be one of the causes of the higher SVR rate in
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
our patients. On the other hand, to develop individualized (personalized) therapy for CHC, elucidating the changeable predictors of SVR and further manipulating them, seems potentially achievable in addition to adjusting the regimens according to the unchangeable viral factors such as HCV genotype. Since IR is considered as a factor that can be modified and improved by various interventions, further prospective studies will be valuable to evaluate whether the effective approaches to improve IR before initiation of the combination therapy for CHC can significantly increase the SVR rate. Poustchi et al. have reported that a significantly higher SVR rate was obtained in patients with a HOMA-IR < 2 (32/34, 94%) than in those with HOMA-IR > 2 (31/48, 65%) in 82 patients with genotypes 2 and 3 infection. Patients with HOMA-IR of <2 were 6.5 times more likely to achieve SVR than those with HOMA-IR > 2, and authors concluded accordingly that the high HOMA-IR is associated with a reduced response [23]. Nevertheless, similar SVR rates were observed among patients with low (91.4%) and high HOMA-IR (84.6%) in our genotype non-1b patients, as well as in the patients with genotype 2 or 3 (92.4% vs. 85.7%). Compared with reports by Poustchi et al. the SVR rate in Taiwanese patients with high HOMA-IR seemed to be higher (84.6% vs. 65%), which seems to account for a higher overall SVR rate in our study (90.6%) than that by Poustchi et al. (76.8%). Whether the better result of treatment for CHC in Taiwanese patients might minimize the impact of IR remains to be clarified. The discrepancies of the observation from different reports need further investigation. Around one- to two-thirds of liver biopsies from CHC patients have histological evidence of steatosis, which has been associated with being overweight, hepatic fibrosis and triglyceride levels [34–36]. There are also associations between IR, steatosis and liver fibrosis observed in CHC patient [36–40]. The report from Conjeevaram et al. has shown IR but not steatosis was independently associated with lower SVR rate [34]. D’Souza et al. has shown IR but not steatosis or fibrosis was independently associated with SVR rate [37]. In the present large-scale study, our results have demonstrated that IR but not steatosis or fibrosis was the most important predictor for response in addition to HCV genotype and viral load, particularly for the ‘‘difficult-to-treat patients”. IR has been suggested as the cause, rather than the consequence, of hepatic steatosis and fibrosis in patients with HCV, particularly those with genotype 1 infection [41]. The mechanisms for more obvious and important influence of IR rather than steatosis and fibrosis might need further study in the future. In conclusion, the present large-scale study in Taiwanese CHC patients showed that pretreatment HOMA-IR was associated with SVR to combination therapy with (PEG-IFN)/ribavirin, in particular among
717
‘‘difficult-to-treat” patients (genotype 1b and high baseline viral loads). These findings suggest clinical application of pretreatment HOMA-IR to predict the outcomes of combination therapy and determine the treatment regimens to maximize the efficacy based on the concept of individualized therapy. Since IR is a potentially modifiable factor, the responses to antiviral therapy for CHC may be improved by modulation of insulin signaling and improvements in IR and glucose control. The tremendous potential for evaluating novel therapies and targets including insulin-sensitizing drugs in CHC patients deserves prospective evaluation. Acknowledgement The authors thank the Taiwan Liver Research Foundation for secretarial and serum processing help. The foundation did not influence how the study was conducted or the way the manuscript was approved. References [1] Mazzaro C, Panarello G, Tesio F, Santini G, Crovatto M, Mazzi G, et al. Hepatitis C virus risk: a hepatitis C virus-related syndrome. J Intern Med 2000;247:535–545. [2] Hadziyannis SJ. The spectrum of extrahepatic manifestations in hepatitis C virus infection. J Viral Hepat 1997;4:9–28. [3] Huang JF, Chuang WL, Dai CY, Ho CK, Hwang SJ, Chen SC, et al. Viral hepatitis and proteinuria in an area endemic for hepatitis B and C infections: Another chain of link? J Intern Med 2006;260:255–262. [4] Simo R, Hernandez C, Genesca J, Jardi R, Mesa J. High prevalence of hepatitis C virus infection in diabetic patients. Diabetes Care 1996;19:998–1000. [5] Mason AL, Lau JY, Hoang N, Qian K, Alexander GJ, Xu L, et al. Association of diabetes mellitus and chronic hepatitis C virus infection. Hepatology 1999;29:328–333. [6] Knobler H, Schihmanter R, Zifroni A, Fenakel G, Schattner A. Increased risk of type 2 diabetes in non-cirrhotic patients with chronic hepatitis C virus infection. Mayo Clin Proc 2000;75:355–359. [7] Dai CY, Chuang WL, Ho CK, Hsieh MY, Huang JF, Lee LP, et al. Associations between hepatitis C viremia and low serum triglyceride and cholesterol levels: a community-based study. J Hepatol 2008;49:9–16. [8] Petrides AS. Liver disease and diabetes mellitus. Diabetes Rev 1994;2:2–18. [9] Petit JM, Bour JB, Galland-Jos C, Minello A, Verges B, Guiguet M, et al. Risk factors for diabetes mellitus and early insulin resistance in chronic hepatitis C. J Hepatol 2001;35:279–283. [10] Hui JM, Sud A, Farrell GC, Bandara P, Byth K, Kench JG, et al. Insulin resistance is associated with chronic hepatitis C virus infection and fibrosis progression. Gastroenterology 2003;125:1695–1704. [11] Taura N, Ichikawa T, Hamasaki K, Nakao K, Nishimura D, Goto T, et al. Association between liver fibrosis and insulin sensitivity in chronic hepatitis C patients. Am J Gastroenterol 2006;101:2752–2759. [12] Svegliati-Baroni G, Bugianesi E, Bouserhal T, Marini F, Ridolfi F, Tarsetti F, et al. Post-load insulin resistance is an independent predictor of hepatic fibrosis in virus C chronic hepatitis and in nonalcoholic fatty liver disease. Gut 2007;56:1296–1301.
718
C.-Y. Dai et al. / Journal of Hepatology 50 (2009) 712–718
[13] Strader DB, Wright T, Thomas DL, Seeff LB. American Association for the Study of Liver Diseases. Diagnosis, management, and treatment of hepatitis C. Hepatology 2004;39: 1147–1171. [14] Fried MW, Shiffman ML, Reddy KR, Smith C, Marinos G, Goncales FL, et al. Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection. N Engl J Med 2002;347:975–982. [15] Sterling RK, Hofmann CM, Luketic VA, Sanyal AJ, Contos MJ, Mills AS, et al. Treatment of chronic hepatitis C virus in the Virginia department of corrections: Can compliance overcome racial differences to response? Am J Gastroenterol 2004;99:866–872. [16] Bressler BL, Guindi M, Tomlinson G, Heathcote J. High body mass index is an independent risk factor for nonresponse to antiviral treatment in chronic hepatitis C. Hepatology 2003;38:639–644. [17] Muir AJ, Bornstein JD, Killenberg PG. Peginterferon alfa-2b and ribavirin for the treatment of chronic hepatitis C in blacks and non-Hispanic whites. N Engl J Med 2004;350:2265–2271. [18] Hadziyannis SJ, Sette Jr H, Morgan TR, Balan V, Diago M, Marcellin P, et al. Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose. Ann Intern Med 2004;140:346–355. [19] Lee SD, Yu ML, Cheng PN, Lai MY, Chao YC, Hwang SJ, et al. Comparison of a 6-month course peginterferon alpha-2b plus ribavirin and interferon alpha-2b plus ribavirin in treating Chinese patients with chronic hepatitis C in Taiwan. J Viral Hepat 2005;12:283–291. [20] Yu ML, Dai CY, Huang JF, Hou NJ, Lee LP, Hsieh MY, et al. A randomized study of peginterferon and ribavirin for 16 vs 24 weeks in patients with genotype 2 chronic hepatitis C. Gut 2007;56:553–559. [21] Yu ML, Dai CY, Huang JF, Chiu CF, Yang YH, Hou NJ, et al. Rapid virological response and treatment duration for chronic hepatitis C genotype 1 patients: A randomized trial. Hepatology 2008;47:1884–1893. [22] Romero-Gomez M, Del Mar Viloria M, Andrade RJ, Salmeron J, Diago M, Fernandez-Rodriguez CM, et al. Insulin resistance impairs sustained response rate to peginterferon plus ribavirin in chronic hepatitis C patients. Gastroenterology 2005;128:636–641. [23] Poustchi H, Negro F, Hui J, Cua IH, Brandt LR, Kench JG, et al. Insulin resistance and response to therapy in patients infected with chronic hepatitis C virus genotypes 2 and 3. J Hepatol 2008;48:28–34. [24] Knodell RG, Ishak KG, Black WC, Chen TS, Craig R, Kaplowitz N, et al. Formulation and application of a numerical scoring system for assessing histological activity in asymptomatic chronic active hepatitis. Hepatology 1982;1:431–435. [25] Scheuer PJ. Classification of chronic viral hepatitis: a need for reassessment. J Hepatol 1991;13:372–374. [26] Kleiner DE, Brunt EM, Van Natta M, Behling C, Contos MJ, Cummings OW, et al. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology 2005;41:1313–1321.
[27] Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentration in man. Diabetologia 1985;28:412–429. [28] Okamoto H, Tokita H, Sakamoto M, Horikita M, Kojima M, Iizuka H, et al. Characterization of the genomic sequence of type V (or 3a) hepatitis C virus isolates and PCR primers for specific detection. J Gen Virol 1993;74:2385–2390. [29] Pacific Association for the Study of the Liver (APASL) Hepatitis C Working Party McCaughan GW, Omata M, Amarapurkar D, et al. Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection. J Gastroenterol Hepatol 2007;22:615–633. [30] Dai CY, Chuang WL, Chang WY, Chen SC, Lee LP, Hsieh MY, et al. Tumor necrosis factor alpha promoter polymorphism at position –308 predicts hepatitis C virus response to combination therapy. J Infect Dis 2006;193:98–101. [31] Labropoulou-Karatza C, Goritsas C, Fragopanagou H, Repandi M, Matsouka P, Alexandrides T. High prevalence of diabetes mellitus among adult b-thalassemic patients with chronic hepatitis C. Eur J Gastroenterol Hepatol 1999;11:1033–1036. [32] Huang JF, Dai CY, Hwang SJ, Ho CK, Hsiao PJ, Hsieh MY, et al. Hepatitis C viremia increases the association with type 2 diabetes mellitus in a hepatitis B and C endemic area: an epidemiological link with virological implication. Am J Gastroenterol 2007;102:1237–1243. [33] Mangia A, Santoro R, Minerva N, Ricci GL, Carretta V, Persico M, et al. Peginterferon alfa-2b and ribavirin for 12 vs. 24 weeks in HCV genotype 2 or 3. N Engl J Med 2005;352:2609–2617. [34] Conjeevaram HS, Kleiner DE, Everhart JE, Hoofnagle JH, Zacks S, Afdhal NH, et al. Race, insulin resistance and hepatic steatosis in chronic hepatitis C. Hepatology 2007;45:80–87. [35] Powell EE, Jonsson JR, Clouston AD. Steatosis: co-factor in other liver diseases. Hepatology 2005;42:5–13. [36] Hsieh MH, Lee LP, Hsieh MY, Tsai KB, Huang JF, Hou NJ, et al. Hepatic steatosis and fibrosis in chronic hepatitis C in Taiwan. Jpn J Infect Dis 2007;60:377–381. [37] D’Souza R, Sabin CA, Foster GR. Insulin resistance plays a significant role in liver fibrosis in chronic hepatitis C and in the response to antiviral therapy. Am J Gastroenterol 2005;100:1509–1515. [38] Muzzi A, Leandro G, Rubbia-Brandt L, James R, Keiser O, Malinverni R, et al. Insulin resistance is associated with liver fibrosis in non-diabetic chronic hepatitis C patients. J Hepatol 2005;42:41–46. [39] Sud A, Hui JM, Farrell GC, Bandara P, Kench JG, Fung C, et al. Improved prediction of fibrosis in chronic hepatitis C using measures of insulin resistance in a probability index. Hepatology 2004;39:1239–1247. [40] Zekry A, McHutchison JG, Diehl AM. Insulin resistance and steatosis in hepatitis C virus infection. Gut 2005;54:903–906. [41] Fartoux L, Poujol-Robert A, Gue’chot J, Wendum D, Poupon R, Serfaty L. Insulin resistance is a cause of steatosis and fibrosis progression in chronic hepatitis C. Gut 2005;54:1003–1008.