Hepatitis C virus infection: evidence for an association with type 2 diabetes

Molecular mechanisms of insulin resistance in chronic hepatitis C

It is now widely recognized that chronic hepatitis C (CHC) is associated with insulin resistance (IR) and type 2 diabetes, so can be considered a metabolic disease. IR is most strongly associated with hepatitis C virus (HCV) genotype 1, in contrast to hepatic steatosis, which is associated with genotype 3 infection. Apart from the well-described complications of diabetes, IR in CHC predicts faster progression to fibrosis and cirrhosis that may culminate in liver failure and hepatocellular carcinoma. More recently, it has been recognized that IR in CHC predicts a poor response to antiviral therapy. The molecular mechanisms for the association between IR and HCV infection are not well defined. This review will elaborate on the clinical associations between CHC and IR and summarize current knowledge regarding the molecular mechanisms that potentially mediate HCV-associated IR.

Prevalence and treatment of hyperlipidemia in patients with chronic hepatitis C infection

BACKGROUND

Patients with chronic hepatitis C (HCV) infection can also have hyperlipidemia. Glucose intolerance has been associated with HCV infection and treating hyperlipidemia in this and other high-risk groups is warranted. We hypothesized that hyperlipidemia is common in patients with hepatitis C and that it is under-treated for fear of worsening liver function.

DESIGN

From the Stratton Veterans Affairs Medical Center computerized database, we collected information on patients with HCV infection enrolled in hepatology clinic. We collected information on age, sex, duration of HCV infection, concomitant diagnoses, medications they were on, laboratory values including hepatic function, glucose, and lipid levels. We collected information on the lipid levels and various cardiovascular risk factors.

METHODS

This is a retrospective study involving record review. We analyzed the data collected from the records for prevalence of high cholesterol (as defined by the National Cholesterol Education Program) and for prevalence of various cardiovascular risk factors. We analyzed prevalence of treatment of hyperlipidemia in various risk groups. In the patients who were treated for hyperlipidemia, we collected information on any worsening hepatic function that led to treatment discontinuation.

RESULTS

Six hundred and twenty-eight (70.5%) out of 891 patients with hepatitis C had hyperlipidemia. Of the 628 patients who had hyperlipidemia, 81 (12.7%) had positive antibody and RNA not tested; 162 (25.4%) had positive antibody but negative RNA testing; and 385 (61.3%) had positive testing for viral RNA. Two hundred and eighty-four (45.2%) of 628 patients with hyperlipidemia were eligible for treatment to lower it. Of 146 patients with hyperlipidemia and diabetes mellitus or arterial disease who were qualified for treatment (LDL >99), 95 (65.1%) were treated with lipid-lowering medication. Of 148 patients with hyperlipidemia and without diabetes or arterial disease who were qualified for treatment, 64 (43.3%) were treated with lipid-lowering medication.

CONCLUSION

A high prevalence of hyperlipidemia in patients infected with HCV is observed. Prevalence is highest among those who are positive for viral RNA. About half the patients with hyperlipidemia were eligible for treatment with drugs to lower it. Treatment of hyperlipidemia with medication though surprisingly common could improve.

Association of hepatitis C virus infection and diabetes in central Tunisia

AIM: To investigate hepatitis C virus (HCV) seroprevalence in Tunisian patients with diabetes mellitus and in a control group.

METHODS: A cross-sectional study was conducted to determine the HCV seroprevalence in 1269 patients with diabetes (452 male, 817 female) and 1315 non-diabetic patients, attending health centers in Sousse, Tunisia. HCV screening was performed in both groups using a fourth-generation enzyme immunoassay.

RESULTS: In the diabetic group, 17 (1.3%) were found to be HCV-infected compared with eight (0.6%) in the control group, although the difference was not significant (P = 0.057). Quantitative PCR was performed in 20 patients. Eleven patients were positive and showed HCV genotype 1b in all cases.

CONCLUSION: Frequency of HCV antibodies was low in patients with diabetes and in the control group in central Tunisia, with no significant difference between the groups.

Amino acid substitutions in the hepatitis C virus core region of genotype 1b are the important predictor of severe insulin resistance in patients without cirrhosis and diabetes mellitus

Previous studies provided a direct experimental evidence for the contribution of HCV core protein in the development of insulin resistance (IR), but the clinical impact of HCV core region on IR is still not clear. The present study evaluated the impact of Amino acid (aa) substitutions of HCV-1b core region on IR in 123 Japanese patients infected with HCV-1b without cirrhosis and diabetes mellitus, and investigated the treatment efficacy of 48-week pegylated interferon (PEG-IFN) plus ribavirin (RBV) according to HOMA-IR values. Patients with IR (HOMA-IR > or = 2.5) and severe IR (HOMA-IR > or = 3.5) were present in 51.2% and 27.6%, respectively. Multivariate analysis identified body mass index (> or = 25 kg/m(2)) and hepatocyte steatosis (> or = 5%) as significant determinants of IR. Furthermore, multivariate analysis identified hepatocyte steatosis (> or = 5%), aa substitutions of the core region (Gln70 (His70) and/or Met91), and age (> or = 55 years) as significant determinants of severe IR. Especially, significantly lower proportions of patients with Gln70 (His70) and/or Met91 were noted among those without severe IR (59.6%) than those with severe IR (82.4%). The rates of sustained virological response in patients with IR (50.0%) were not significantly different from those without IR (52.9%). Furthermore, the rates of non-virological response in patients with IR (28.9%) were not significantly also different from those without IR (20.6%). In conclusion, the present study indicated that substitutions of HCV-1b core region were the important predictor of severe IR in patients without cirrhosis and diabetes mellitus, but HOMA-IR values might be not useful as predictors of 48-week PEG-IFN plus RBV therapy.

Prevalence of glucose intolerance in patients with chronic hepatitis B or C: a prospective case-control study

Despite several studies, the association of glucose intolerance with chronic hepatitis B (CHB) or C (CHC) virus infection remains controversial. We evaluated the prevalence of glucose intolerance by oral glucose tolerance test (OGTT) in patients with CHB or CHC in comparison with matched controls. In total, 189 consecutive outpatients with CHB or CHC and 189 subjects individually matched for age, sex and body mass index (BMI) were included. OGTT was performed in all cases, except in known diabetics, and glucose intolerance was defined as impaired glucose tolerance (IGT), OGTT-diabetes or known diabetes. Most patients with abnormal OGTT had normal fasting glucose (IGT: 69.8%, OGTT-diabetes: 54.5%). Compared with their own controls, CHB patients had a higher prevalence of IGT (13.6% vs 2.5%, P = 0.018) and family history of diabetes (34.6% vs 16.0%, P = 0.011), while CHC patents had higher prevalence of glucose intolerance (37.0% vs 15.7%, Rho = 0.001), mostly because of more frequent IGT (21.3% vs 6.5%, Rho = 0.003). After age and BMI adjustment, patients with CHC compared with those with CHB had significantly higher prevalence of glucose intolerance (37.0% vs 29.6%, P = 0.037). In conclusion, increased prevalence of glucose intolerance is documented by OGTT both in CHC and CHB patients compared with age, sex and BMI matched controls. Glucose intolerance is more frequent in CHC than CHB patients, regardless of known risk factors. An OGTT might be necessary at the baseline work-up of CHB or CHC patients, as a normal fasting glucose value does not exclude IGT or OGTT-diabetes.

Endocrine manifestations of hepatitis C virus infection

Chronic infection with hepatitis C virus (HCV) can result in both hepatic and extrahepatic disease and endocrine dysfunction represents an important class of HCV-related extrahepatic disease. The most frequently occurring--and clinically important--of these endocrine disorders are thyroid disease and type 2 diabetes mellitus. In this Review, we evaluate the evidence in support of a link between HCV infection and endocrine-system dysfunction, and discuss potential pathophysiological mechanisms. A meta-analysis of the literature has revealed significant associations between chronic HCV infection, thyroid autoimmunity and hypothyroidism. Furthermore, a high prevalence of thyroid cancer has been reported in HCV-positive patients. Several clinicoepidemiological studies have demonstrated that chronic HCV infection could lead to the development of type 2 diabetes mellitus, possibly as a result of HCV-induced metabolic disturbances. Some researchers have postulated that a type 1 T-helper -cell mediated immune response underpins the association of chronic HCV infection with endocrine disease. Indeed, the available data suggest that a common immunological, type 1 T-helper cell pattern of cytokine expression and activation (via interferon-gamma) could provide the pathophysiological basis for this association. Nonetheless, additional studies will be necessary to elucidate fully all the mechanisms involved in HCV-related endocrine dysfunction.

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.

Hepatitis C and diabetes: the inevitable coincidence?

Type 2 diabetes (T2D) and HCV infection are common conditions involving, respectively, at least 170 and 130 million people worldwide. However, the distribution of such cases does not overlap in the same age groups in different geographic areas. Following pioneering reports of increased prevalence of T2D in HCV-positive cirrhosis, interest concerning the relationship between HCV and T2D has escalated. HCV is able to induce insulin resistance (IR) directly and the role of specific viral genotypes responsible for such effect is disputed. IR has consistently been found to be closely linked to fibrosis in HCV infection, although also typically associated with T2D in prefibrotic stages. HCV infection could be associated with a reduced prevalence of metabolic syndrome owing to virus-associated reduction in BMI (reported in population but not clinical studies) and hypobetaliproteinemia. A three- to ten-fold increased risk of HCV infection was reported among diabetic patients in comparison with different control groups and a meta-analysis showed a 1.8-fold excess risk of T2D among HCV-positive compared with HBV-positive patients. Moreover, HCV positivity is associated with an increased risk of T2D in patients receiving liver or kidney transplantations. T2D and IR are independent predictors of a more rapid progression of liver fibrosis and impaired response to antiviral treatment in chronic hepatitis C. Patients with cirrhosis and T2D have an increased susceptibility to hepatic encephalopathy and hepatocellular carcinoma (HCC). However, the beneficial effects of antiviral treatment on IR and T2D are controversial. Theoretically, glycemic control in chronic hepatitis C, and particularly in cirrhotic patients, could improve the prognosis and the response to antivirals, although the evidence for this is limited. Future studies should elucidate the relationship between insulin signaling, HCV and interferon signaling, entity of cardiovascular risk in patients with HCV infection, the potential role of 'metabolic' strategies added to antiviral treatment schedules, the impact of IR on liver failure, portal hypertension and HCC, particularly in patients managed in a transplant setting.

Serological evidence of infections and Type 2 diabetes: the MultiEthnic Study of Atherosclerosis

AIMS

Prospective studies have identified chronic inflammation as a risk factor for Type 2 diabetes. However, it is not known whether infection by specific pathogens or having a greater 'pathogen burden' is associated with diabetes. The aim of this study was to examine the cross-sectional relation of seropositivity to five pathogens (Chlamydia pneumoniae, cytomegalovirus, Helicobacter pylori, hepatitis A virus, herpes simplex virus) and prevalent diabetes.

METHODS

Baseline data from a random sample of MultiEthnic Study of Atherosclerosis (MESA) participants (n = 1000; age 45-84 years) were used. Diabetes was defined by American Diabetes Association 2003 criteria, and 'pathogen burden' by the number of pathogens (0-5) for which an individual was seropositive. Logistic regression was used to test differences in diabetes prevalence by seropositivity. Linear regression was used to explore associations between pathogen seropositivity and the inflammation markers C-reactive protein, interleukin-6 and fibrinogen.

RESULTS

Diabetes prevalence was 12.7%, whereas seropositivity for C. pnuemoniae was 76%, cytomegalovirus 77%, H. pylori 45%, hepatitis A 58% and herpes simplex virus 85%. Seventy-two percent were seropositive for three or more pathogens. In crude analyses, the prevalence of diabetes was higher among those with a pathogen burden of three or more, and with seropositivity to cytomegalovirus, H. pylori, hepatitis A and herpes simplex virus. After adjustment for demographic covariates (particularly race), all associations became non-significant. Pathogen seropositivity was also not related to inflammation marker levels.

CONCLUSIONS

Following demographic adjustments, no associations were observed between infection by several pathogens and diabetes status, suggesting no aetiological role for them in the occurrence of diabetes.

Cirrhosis of mixed etiology (hepatitis C virus and alcohol): Posttransplantation outcome-Comparison with hepatitis C virus-related cirrhosis and alcoholic-related cirrhosis

Hepatitis C virus (HCV)-related liver disease is enhanced by alcohol consumption. Of HCV-related liver transplantation (LT) recipients, 25% have a history of alcohol intake. The purpose of this research was to determine whether LT outcome differs between patients with cirrhosis of mixed etiology compared to HCV or alcohol alone. Of 494 LT (1997-2001), recipient/donor features, post-LT histological, metabolic complications [hypertension, diabetes-diabetes mellitus (DM)], and de novo tumors were compared in 3 groups [HCV-related cirrhosis = 170 (HCV group), alcohol-related cirrhosis (alcohol group) = 107, and cirrhosis of mixed etiology (mixed group) = 60]. Protocol biopsies were done in HCV patients. Severe recurrent HCV disease was defined as: 1-year fibrosis >1, cholestatic hepatitis, recurrent cirrhosis, or HCV-related liver retransplantation (reLT) within 5 years. Patients in the mixed group were younger (mean age: HCV group = 59 years; mixed group = 49 years; alcohol group = 53 years; P < 0.05) and mainly men (% men: HCV group = 51%; mixed group = 97%; alcohol group = 87%). Hepatocellular carcinoma (HCC) was more frequent in HCV patients (HCV group = 44%; mixed group = 35%; alcohol group = 18%; P = 0.05). Five-year survival was lowest in the HCV group (HCV group = 49% versus mixed group = 73% versus alcohol group = 76%; and P < 0.01 for the HCV group versus the alcohol group or the HCV group versus the mixed group; P = 0.74 for the alcohol group versus the mixed group). Metabolic complications and de novo tumors were more frequent in the alcohol groups. Severe HCV disease was similar in the HCV+ groups (HCV group = 45%; mixed group = 45%; P = 0.66). Patients with in the mixed group were more frequently treated with antivirals (32% versus HCV group = 18%; P = 0.03). In HCV patients, factors independently associated with lower survival were older donor age, LT indication (HCV alone), and increased body mass index (BMI). Antiviral therapy was a protective factor. Post-LT survival was lower in the isolated HCV group compared to the alcohol or mixed groups despite a similar recurrence of HCV disease. A greater use of antiviral therapy in the mixed group may explain these differences. The incidence of metabolic complications and de novo tumors was greater in the alcohol groups.

Hepatitis C infection and risk of diabetes: a systematic review and meta-analysis

BACKGROUND/AIMS

Several studies found hepatitis C (HCV) increases risk of Type II diabetes mellitus (DM). However, others found no or only sub-group specific excess risk. We performed meta-analyses to examine whether HCV infection does increase DM risk in comparison to the general population and in other sub-groups with increased liver disease rates including with hepatitis B (HBV).

METHODS

We followed standard guidelines for performance of meta-analyses. Two independent investigators identified eligible studies through structured keyword searches in relevant databases including PubMed.

RESULTS

We identified 34 eligible studies. Pooled estimators indicated significant DM risk in HCV-infected cases in comparison to non-infected controls in both retrospective (OR(adjusted)=1.68, 95% CI 1.15-2.20) and prospective studies (HR(adjusted)=1.67, 95% CI 1.28-2.06). Excess risk was also observed in comparison to HBV-infected controls (OR(adjusted)=1.80, 95% CI 1.20-1.40) with suggestive excess observed in HCV+/HIV+ cases in comparison to HIV+ controls (OR(unadjusted)=1.82, 95% CI 1.27-2.38).

CONCLUSIONS

Our finding of excess DM risk with HCV infection in comparison to non-infected controls is strengthened by consistency of results from both prospective and retrospective studies. The excess risk observed in comparison to HBV-infected controls suggests a potential direct viral role in promoting DM risk, but this needs to be further examined.

Immunopathogenesis of HCV-related endocrine manifestations in chronic hepatitis and mixed cryoglobulinemia

Hepatitis C Virus (HCV) is known to be responsible for both hepatic and extrahepatic diseases (HCV-related extrahepatic diseases = HCV-EHDs). The most important systemic HCV-EHDs are mixed cryoglobulinemia and lymphoproliferative disorders, while the most frequent and clinically important endocrine HCV-EHDs are thyroid disorders and type 2 diabetes mellitus (T2D). From a meta-analysis of the literature a significant association between HCV infection and thyroid autoimmunity and hypothyroidism has been reported. A high prevalence of thyroid cancer has been reported, too. Furthermore, several clinical epidemiologic studies have reported that HCV infection is associated to T2D. Many studies have linked Th1 immune response with HCV infection, thyroid autoimmunity, or diabetes. These findings suggest that a possible common immunological Th1 pattern could be the pathophysiological base of the association of HCV-EHDs, with thyroid autoimmunity and T2D. In fact, HCV infection of thyrocytes or beta-cells may act by upregulating CXCL10 secretion in these cells that is responsible for Th1 lymphocyte recruitment. Th1 response leads to increased IFNgamma and TNFalpha production that in turn stimulates CXCL10 secretion by the target cells, thus perpetuating the immune cascade. This process may lead to the appearance of thyroid autoimmune disorders or T2D in genetically predisposed subjects.

Extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus may cause hepatic and extrahepatic diseases. Extrahepatic manifestations range from disorders for which a significant association with viral infection is supported by epidemiologic and pathogenetic data, to anecdotal observations without clear proof of causality. This article describes the diagnosis and treatment of these diseases.

Dysmetabolic changes associated with HCV: a distinct syndrome?

Although not associated with the metabolic syndrome, HCV is linked with impaired insulin signalling, insulin resistance, hypocholesterolemia and steatosis which represent a distinct HCV-associated dysmetabolic syndrome. Insulin resistance affects the development of diabetes, fibrosis, impaired response to antivirals and perhaps hepatocellular carcinoma risk. HCV infection is associated with hypocholesterolemia and steatosis reversible after sustained virologic response. A "viral", and a "metabolic" steatosis exist as function of viral genotypes. Little is known about the possible role of HCV in further components of the metabolic syndrome such as atherosclerosis, obesity, arterial hypertension, hyperuricemia and thrombotic risk factors.

Metabolic profiles in patients with chronic hepatitis C: a case-control study

BACKGROUND

The clinical implications of metabolic profiles in patients with chronic hepatitis C remain controversial. To study the association of metabolic abnormalities with chronic hepatitis C, we conducted a case-control study with special emphasis on serum lipid pattern, fasting blood glucose, and adiponectin.

METHODS

We enrolled 500 patients with chronic hepatitis C and 536 sex and age-matched controls. Unadjusted and adjusted associations of demographic and metabolic variables were estimated.

RESULTS

Chronic hepatitis C patients had higher alanine aminotransferase (ALT) and high-density lipoprotein-cholesterol levels, but lower total cholesterol (TC), triglyceride (TG), and low-density lipoprotein-cholesterol levels than controls. Stratifying ALT level according to its upper limit of normal, HCV infection was associated with younger age, female gender, and higher TC levels in chronic hepatitis C patients with normal ALT levels, but with lower TC and lower TG levels in those with abnormal ALT levels. By using multiple linear regression analyses for subjects with available adiponectin data, presence of HCV infection was independently associated with higher serum adiponectin levels.

CONCLUSIONS

Metabolic profiles of chronic hepatitis C patients are affected by age, gender, serum adiponectin, and ALT levels. Further longitudinal studies are needed to clarify the complex interplay between HCV infection and metabolic profiles.

Prevalence of elevated liver enzymes in Type 2 diabetes mellitus and its association with the metabolic syndrome

The occurrence of liver disease and raised liver enzymes is common in Type 2 diabetes, and may be multifactorial in origin. Very few studies are available on the exact prevalence of the phenomenon, however. We carried out an observational point-prevalence study of elevated liver enzymes in eight hospital-based Italian diabetes units. Data of 9621 consecutive Type 2 diabetes patients (males, 52.4%; median age, 65 yr) were analyzed, and alanine and aspartate aminotransferase (ALT, AST) and gamma-glutamyltransferase (GGT) levels were related to body mass index (BMI), metabolic control and the presence of the metabolic syndrome. ALT, AST, and GGT levels exceeding the upper limit of normal were present in 16.0%, 8.8%, 23.1%, respectively, the prevalence being higher in males, increasing with obesity class and poor metabolic control, and decreasing with age. Elevated enzymes were systematically associated with most parameters of the metabolic syndrome. After correction for age, gender, BMI, and differences across centers, elevated triglyceride levels/fibrate treatment [odds ratio (OR), 1.57; 95% confidence interval (CI), 1.34- 1.84] and an enlarged waist circumference (OR, 1.47; 95% CI, 1.17-1.85) were the only parameters independently associated with high ALT. In a separate analysis, the presence of metabolic syndrome (Adult Treatment Panel III criteria) was highly predictive of raised liver enzymes. After exclusion of hepatitis B and C positive cases, tested in 2 centers, the prevalence of raised enzymes decreased by approximately 4%, but the association with the metabolic syndrome did not change significantly. In conclusion, the high prevalence of elevated liver enzymes in Type 2 diabetes is in keeping with the well-demonstrated risk of progressive liver disease. A large amount of diabetes patients may require a thorough clinical, laboratory and histological investigation.

Hepatitis C virus (HCV) infection: a systemic disease

Hepatitis C virus (HCV) infection is a global health problem, being the second most common chronic viral infection in the world with a global prevalence of about 3% (about 180 million people). HCV is both an hepatotropic and a lymphotropic virus; and chronic infection could cause, on one hand, chronic hepatitis, cirrhosis and hepatocellular carcinoma and on the other hand several extrahepatic diseases including, first, mixed cryoglobulinemia and lymphoma. The association between hepatic (hepatocellular carcinoma) and extrahepatic (lymphoma, thyroid cancer) malignancies has justified the inclusion of HCV among human cancer viruses. The pathogenesis of HCV-related sequelae (hepatic or extrahepatic) is not fully understood representing a challenge of prime importance in light of the optimization of clinico-therapeutic management of these patients. Combined treatment with pegylated interferon plus ribavirin is presently the first-line, gold standard treatment of most HCV-related diseases. However, mainly in the case of extrahepatic manifestations, a cautious approach to the patient, with a case to case accurate tailoring of therapy is frequently requested. The present review will outline the principal aspects of such HCV-induced systemic disease focusing on extrahepatic manifestations.

HCV-related autoimmune and neoplastic disorders: the HCV syndrome

Hepatitis C virus (HCV) chronic infection may be associated with a great number of both hepatic and extrahepatic manifestations. HCV lymphotropism is responsible for poly-oligoclonal B-lymphocyte expansion, which is the common underlying alteration in a significant percentage of HCV-infected individuals. The consequent production of different autoantibodies and immune-complexes, including cryoglobulins, may lead to organ- and non-organ-specific immunological alterations. Mixed cryoglobulinemia, a small-vessel systemic vasculitis, is characterized by the coexistence of autoimmune and lymphoproliferative alterations; therefore, it represents the prototype of HCV-associated disorders. Moreover, HCV shows an oncogenic potential; several studies support its pathogenetic link with some malignancies, mainly hepatocellular carcinoma and B-cell lymphomas. On the whole, HCV-related disorders present a heterogeneous geographical distribution, suggesting a role of other important genetic and/or environmental cofactors. While the majority of HCV-infected individuals is asymptomatic or may develop only liver manifestations, a significant percentage of them may develop a variable combination of autoimmune lymphoproliferative disorders. The resulting multiform clinico-pathological condition can be termed HCV syndrome. The natural history of HCV syndrome is the expression of multifactorial and multistep pathogenetic process, which usually proceeds from mild, often isolated manifestations to systemic immune-mediated disorders, and less frequently to overt malignancies.

HCV and diabetes. A two-question-based reappraisal

We used available studies to answer two clinically relevant questions, i.e. whether those with type 2 diabetes should undergo hepatitis C virus screening and whether hepatitis C virus positive individuals should be screened for diabetes. Four reasons argue against the hypothesis of screening diabetics for hepatitis C virus. First, although it induces insulin resistance, hepatitis C virus is not directly diabetogenic. Second, the clinical phenotype of hepatitis C virus-associated type 2 diabetes might be a clue to target the specific diabetic population to be screened. Third, diabetic patients are expected to be poor responders to antivirals and evidence that this might result in recovery from type 2 diabetes is insufficient. Fourth, no econometric data are available in the specific subset of those with type 2 diabetes. Case finding of type 2 diabetes in those with hepatitis C virus infection, in contrast, might be considered in those patients with type 2 diabetes who have cirrhosis, in whom--due to increased prevalence and severity of hepatic encephalopathy--diabetes is associated with increased mortality. Preliminary evidence suggests that the prognosis of cirrhosis might benefit from improved glycemic control and thus from earlier diagnosis of type 2 diabetes. Finally, studies are needed to ascertain the most cost-effective strategy of case-finding type 2 diabetes among those who are hepatitis C virus-infected. In conclusion, available data enabled us to answer the two questions. Hepatitis C virus screening should best be restricted to those (lean) diabetic patients with (advanced) liver disease. Glucose tolerance testing should best be performed in those with hepatitis C virus-related cirrhosis. However, additional studies are needed to support the cost-effectiveness of our conclusions.

The multifaceted associations of hepatobiliary disease and diabetes

OBJECTIVE

To investigate the association of diabetes and hepatobiliary disease.

METHODS

We performed a MEDLINE search of the English-language literature published between January 1980 and January 2007 for studies in which diabetes was associated with liver diseases.

RESULTS

Through its association with the insulin resistance syndrome, type 2 diabetes is associated with nonalcoholic fatty liver disease, nonalcoholic steatohepatitis (NASH), NASH-cirrhosis, and NASH-cirrhosis-related hepatocellular carcinoma. Because of the association with insulin resistance, insulin sensitizers may slow or even arrest the progress of these diseases. Type 2 but not type 1 diabetes is associated with hepatitis C virus but not hepatitis B viral infection. This association is likely due to hepatitis C viral infection of the pancreatic beta-cells. Early detection and antiviral therapy can decelerate the development of diabetes. Type 1 diabetes is associated with hemochromatosis and autoimmune hepatitis. Because of the presence of autonomic neuropathy, cholelithiasis but not cholecystitis is more common in patients with diabetes than in the general population. Therefore, asymptomatic cholelithiasis in patients with diabetes no longer warrants a cholecystectomy. In patients with advanced liver disease of any cause, insulin resistance and diabetes have an increased frequency of occurrence and can be reversed with liver transplantation. Rarely, medications used to treat type 2 diabetes have been associated with drug-induced hepatitis.

CONCLUSION

The prevalence of hepatobiliary diseases is increased in patients with diabetes. Early recognition and treatment of these conditions can prevent, stabilize, or even reverse hepatic damage and prevent the development of hepatic carcinoma and liver failure.

Liver enzymes as a predictor for incident diabetes in a Japanese population: the Hisayama study

OBJECTIVE

We studied the relationship between liver enzymes and the development of diabetes in a general Japanese population.

RESEARCH METHODS AND PROCEDURES

A total of 1804 non-diabetic subjects 40 to 79 years of age were followed-up prospectively for a mean of 9.0 years.

RESULTS

During the follow-up, 135 subjects developed diabetes. In both sexes, the age-adjusted cumulative incidence of diabetes increased significantly with elevating quartiles of serum gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) levels. This pattern was also observed in aspartate aminotransferase (AST) quartiles for men but not for women. In multivariate analyses after adjusting for comprehensive risk factors and other liver enzymes, the risk of developing diabetes was significantly higher in the highest GGT quartile than in the lowest quartile [odds ratio (OR), 2.54; 95% confidence interval (CI), 1.03 to 6.26 for men; OR, 5.73; 95% CI, 1.62 to 20.19 for women]. Similar results were observed in ALT quartiles (OR, 2.32; 95% CI, 0.91 to 5.92 for men; OR, 4.40; 95% CI, 1.38 to 14.06 for women) but not in AST quartiles in either sex. Significant positive associations of GGT and ALT with diabetes were seen within each stratified category of risk factors, namely fasting insulin, BMI, waist-to-hip ratio, high-sensitivity C-reactive protein, and alcohol consumption. In receiver operating characteristic analyses, the areas under the receiver operating characteristic curve of GGT and ALT were significantly larger than that of AST, fasting insulin, waist-to-hip ratio, or C-reactive protein.

DISCUSSION

Our findings suggest that serum GGT and ALT concentrations are strong predictors of diabetes in the general population, independent of known risk factors.

Association between chronic hepatitis B virus infection and diabetes among Asian Americans and Pacific Islanders

BACKGROUND

Asians have a higher prevalence of both diabetes (diabetes mellitus) and chronic hepatitis B virus infection compared to Caucasians. The aim of this study was to investigate whether hepatitis B virus infection was associated with diabetes mellitus among Asian Americans and Pacific Islanders.

METHODS

We reviewed the electronic medical records of 411 Asian and 424 Pacific Islanders seen at our medical centre over a 5-year period. Diabetes mellitus was defined by the presence of two or more random blood glucose levels > or =200mg/dL, an ICD-9 diagnostic code of diabetes mellitus, or use of medications for diabetes mellitus. Hepatitis B virus infection was defined by a positive HBsAg test.

RESULTS

Diabetes mellitus was diagnosed in 223 of the 835 subjects (26.7%), whereas hepatitis B virus infection was diagnosed in 56 (13.8%) of the 407 subjects tested for HBsAg. Overall, the prevalence of diabetes mellitus was significantly higher in patients with hepatitis B virus than in those without hepatitis B virus (58.9% vs. 33.3%, P<0.001), and this remained significant after adjustment for potential confounding variables (OR=3.17; 95% CI, 1.58-6.35). When Asians and Pacific Islanders were analysed separately, the prevalence of diabetes mellitus in patients with hepatitis B virus was significantly higher than in those without hepatitis B virus among Asians (65.0% vs. 27.5%, P<0.001) but not in Pacific Islanders (43.8% vs. 37.1%, P=0.60). Among the 390 subjects who were tested for both hepatitis B virus and hepatitis C virus, the prevalence of diabetes mellitus was 29.4% in uninfected subjects, 44.4% in patients with hepatitis B virus monoinfection, 47.2% in patients with hepatitis C virus monoinfection and 85.0% in patients with hepatitis B virus and hepatitis C virus coinfection (P<0.001).

CONCLUSIONS

Hepatitis B virus infection is strongly associated with diabetes mellitus among Asian Americans, but not in Pacific Islanders, whereas hepatitis C virus infection was associated with diabetes mellitus in both ethnic groups.

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

OBJECTIVES

There is growing evidence with regard to the association between hepatitis C virus (HCV) infection and type 2 diabetes mellitus (T2DM). However, the mutual link and related virological implication have not been fully clarified. The impact of hepatitis B virus (HBV) infection on the epidemiological link remains unclear. This study aimed to elucidate the link between T2DM and viral hepatitis infections, especially HCV infection. It also aimed to analyze the associated virological characteristics and implication.

METHODS

Cross-sectional analysis of a computer-sampling survey among 10,975 participants (aged 40-65 yr) was performed in an area endemic for HBV and HCV infections in Taiwan. Outcome measures included prevalence of T2DM among different groups of viral hepatitis infection, and comparison of related biochemical and virological profiles.

RESULTS

Of 10,975 participants studied, 9,932 eligible participants were analyzed. The prevalence of T2DM, seropositivity for HBV surface antigen (HBsAg) and HCV antibodies (anti-HCV), and HCV viremia was 12.5%, 13.1%, 6.5%, and 4.8%, respectively. Prevalence of HCV viremia showed significant difference between T2DM and non-T2DM subjects (6.9% vs 4.5%, P<0.001), whereas anti-HCV seropositivity showed borderline significance (7.8% vs 6.3%, P=0.047). There was no HCV genotype-specific difference between HCV genotype 1 and 2 in the association with T2DM. On the other side, the prevalence of HBsAg (+) did not differ between T2DM and non-T2DM subjects (12.5% vs 13.9%, P=0.19). The prevalence of T2DM among HCV viremic subjects (18.0%, 86/478) was significantly higher than HBsAg (+) subjects (11.4%, 155/1,363, P=0.001) and those negative for both viral hepatitis markers (12.5%, 997/8,004, P=0.001). Multivariate logistic regression analyses showed that HCV viremia was the leading significant factor associated with T2DM, followed by male gender, hypertension, body mass index, and age.

CONCLUSIONS

HBV infection did not increase the association with T2DM. A significant mutual link between T2DM and HCV viremia existed in this HBV/HCV endemic area. There was no HCV genotype-specific difference between HCV genotype 1 and 2 in the association with T2DM.

B-cells and mixed cryoglobulinemia

Mixed cryoglobulinemia (MC) is a systemic small-vessel vasculitis; B-cell expansion is the biological substrate of the disease. It can be regarded as benign lymphoproliferative condition that may evolve to frank lymphoma. HCV infection is the main causative factor of MC, as well as of other overlapping disorders, through multifactorial and multistep pathogenetic process. HCV-related B-cell proliferation represents an important model of virus-driven autoimmune/neoplastic disorder. The term HCV syndrome is referred to a wide spectrum of both hepatic and extrahepatic disorders. The present review analyzes the complex virological, clinico-pathological, and therapeutic implications of B-cell proliferation, with or without HCV infection, in MC patients.

Extrahepatic manifestations of Hepatitis C Virus infection: a general overview and guidelines for a clinical approach

Hepatitis C Virus is associated with a wide series of extrahepatic manifestations. Based on available data the link between the virus and some of these extrahepatic diseases is only suggested and needs further confirmation. Hepatitis C Virus-related lymphoproliferative disorders, whose prototype is mixed cryoglobulinaemia, represent the most closely related extrahepatic manifestations of Hepatitis C Virus. Other Hepatitis C Virus-associated disorders include nephropathies, thyreopathies, sicca syndrome, idiopathic pulmonary fibrosis, porphyria cutanea tarda, lichen planus, diabetes, chronic polyarthritis, cardiopathy and atherosclerosis. A pathogenetic link between Hepatitis C Virus and some extrahepatic manifestations was confirmed by their responsiveness to antiviral therapy, which is now deemed the first therapeutic option to consider. By contrast, there are diseases where treatment with interferon was ineffective or dangerous. The aim of the present paper is to outline the most recent evidence concerning extrahepatic disorders that are possibly associated with Hepatitis C Virus infection. Special emphasis will be given to discussion of the most appropriate clinical approaches to be adopted in order to diagnose, treat (possibly prevent) and follow-up extrahepathic diseases in patients with Hepatitis C Virus infection.

Chronic hepatitis B viral infection independently predicts renal outcome in type 2 diabetic patients

AIMS/HYPOTHESIS

We examined the association between chronic hepatitis B virus (HBV) infection and clinical outcomes in a consecutive cohort of Chinese patients with type 2 diabetes.

SUBJECTS, MATERIALS AND METHODS

Between 1995 and 1999, 2,838 type 2 diabetes patients underwent comprehensive assessments and blood screening for hepatitis B surface antigen (HBsAg). The risk of occurrence of cardiovascular events and end-stage renal disease (defined as need for dialysis, doubling of serum creatinine or serum creatinine > or =500 micromol/l) was compared between HBsAg-positive and HBsAg-negative groups.

RESULTS

At baseline, HBV-infected patients (n=286, 10.1%) were younger (51.0+/-11.5 vs 53.7+/-12.7 years, p=0.004), had earlier onset of diabetes (51.0+/-11.5 vs 53.7+/-12.7 years, p=0.001) and a higher frequency of retinopathy (28 vs 22%, p=0.03) than non-HBV-infected patients. After a median follow-up of 3.5 years (interquartile range: 1.7-5.9 years) and adjustment of age, glycaemic control and other potential confounding factors, HBV-infected patients were more likely to develop end-stage renal disease than non-HBV infected patients (8.7 vs 6.4%) with a hazard ratio of 4.5 (95% CI 1.1-18.6). The difference in the frequency of cardiovascular endpoints was not statistically significant.

CONCLUSIONS

In Chinese type 2 diabetes patients, chronic HBV infection was associated with increased risk of end-stage renal disease, and this was independent of other potential confounding factors. Early identification of HBV status and close surveillance of renal function are important in patients with type 2 diabetes who are living in areas where HBV is endemic or who are at risk of chronic HBV infection.