Relationship between hepatitis C and microalbuminuria: Results from the NHANES III

Hepatitis C virus infection is associated with proteinuria according to a systematic review with meta-analysis

INTRODUCTION AND AIM

Hepatitis C virus infection and chronic kidney disease are major public health issues all over the world. It has been suggested a role of HCV as a risk factor for the development and progression of chronic kidney disease (defined by reduced glomerular filtration rate and/or detectable proteinuria) in the general population but conflicting findings have been given.

MATERIAL AND METHODS

A systematic review of the published medical literature was conducted to assess whether positive HCV serologic status is associated with greater rate of proteinuria in the adult general population. We used a random-effect model to generate a summary estimate of the relative risk of proteinuria with HCV across the published studies.

RESULTS

We identified 23 studies (n=198,967 unique patients) and performed separate meta-analyses according to the study design. Overall effect estimate was significant in cross-sectional (OR, 1.47, 95%CI, 1.3; 1.66) (P<0.001) and obvious between-study heterogeneity was observed (Q value by Chi-squared [χ2] test 27.3, P=0.02). The risk of proteinuria after exposure to HCV was also consistent among longitudinal studies (HR, 1.79, 95% CI, 1.17; 2.74) (P<0.001) and between-study heterogeneity occurred (Q value, 27.82 by X2 test, P=0.0001). Stratified analysis did not report heterogeneity in several comparisons-pooling studies based on urine protein/creatinine ratio (UACR) showed that the adjusted OR with HCV was 1.64 (95% CI, 1.41; 1.91, P<0.001) without heterogeneity (Q value by Chi-squared [χ2] test 9.98, P=NS). Meta-regression recorded a link between greater prevalence of proteinuria in males with HCV exposure (P=0.03). Studies based on univariate analysis (n=6, n=72, 551 unique patients) gave similar results, pooled OR 1.54 (95% CI, 1.08; 2.19) (P=0.0001).

CONCLUSIONS

An important relationship between HCV infection and higher risk of proteinuria in the general population exists. Research aimed to understand the biological mechanisms underlying such association is under way. We encourage to screen all patients with HCV exposure for proteinuria.

Hepatitis C virus antibody seropositivity is associated with albuminuria but not peripheral artery disease in patients with type 2 diabetes

Hepatitis C virus (HCV) infection is prevalent in patients with type 2 diabetes mellitus (DM). We aimed to investigate whether HCV antibody (Ab) seropositivity is associated with diabetic micro- and macro-vascular diseases. In this hospital-based cross-sectional study, we retrospectively collected data from patients who participated in the diabetes pay-for-performance program and underwent HCV Ab screening in the annual comprehensive assessment between January 2021 and March 2022. We examined the relationships of HCV Ab seropositivity with the spot urinary albumin-to-creatinine ratio (UACR) and ankle-brachial index (ABI) in patients aged ≥ 50 years with type 2 DM. A total of 1758 patients were enrolled, and 85 (4.83%) of the enrolled patients had HCV Ab seropositivity. Multivariable regression analyses revealed that albuminuria showed a dose-dependent association with HCV Ab seropositivity (UACR [30-299 mg/g]: odds ratio [OR] = 1.463, 95% confidence interval [CI] 0.872‒2.456); UACR [≥ 300 mg/g]: OR = 2.300, 95% CI 1.160‒4.562; P for trend = 0.015) when compared with normal albuminuria (UACR < 30 mg/g). However, the proportion of patients with peripheral arterial disease, defined as an ABI ≤ 0.9, was not significantly different between the groups with and without HCV Ab seropositivity (3.5% vs. 3.9%, P = 0.999). In conclusion, severely increased albuminuria, but not the ABI, showed a significant association with HCV Ab seropositivity in patients aged ≥ 50 years with type 2 DM.

From Bench to Bedside: Clinical and Biomedical Investigations on Hepatitis C Virus (HCV) Genotypes and Risk Factors for Albuminuria

An extrahepatic manifestation of nephropathies can be a feature of the chronic hepatitis C virus (HCV) infection. Albuminuria is a major risk factor for nephropathies and chronic kidney disease (CKD). The correlation between HCV genotypes and albuminuria is still unclear. In this study, investigations have been done for the biomedical tools and methodologies used in the National Health and Nutrition Examination Survey (NHANES) public database. We searched the 2007−2016 NHANES public database to retrieve data regarding the different HCV genotypes and clinical scenarios. This study attempted to investigate the impacts of HCV genetic diversity, associated comorbidities, and racial differences on albuminuria. The urine albumin/creatinine ratio (ACR) was the primary endpoint. Among 40,856 participants, 336 participants with positive and 237 with negative HCV RNA tests were analyzed, excluding 14,454 participants with negative HCV antibodies and 25,828 which were missed. After controlling for sex, race, education level, smoking, diabetes mellitus, hepatitis B, alcohol use, and body mass index (BMI) with a generalized linear equation, HCV genotype 2 was more likely than any other genotype to cause albuminuria based on the urine ACR (p < 0.001). The generalized linear equation also demonstrated a significantly higher urine ACR, including hepatitis B (p < 0.001), diabetes mellitus (p < 0.001), and smoking (p = 0.026). In summary, the patients with HCV genotype 2 presented with increased albuminuria in comparison with other HCV genotypes in this 10-year retrospective analysis. HCV infection could be a risk factor of CKD; early diagnosis and appropriate treatment may improve clinical outcomes.

Urinary levels of pro-fibrotic transglutaminase 2 (TG2) may help predict progression of chronic kidney disease

Renal clinical chemistry only detects kidney dysfunction after considerable damage has occurred and is imperfect in predicting long term outcomes. Consequently, more sensitive markers of early damage and better predictors of progression are being urgently sought, to better support clinical decisions and support shorter clinical trials. Transglutaminase 2 (TG2) is strongly implicated in the fibrotic remodeling that drives chronic kidney disease (CKD). We hypothesized that urinary TG2 and its ε-(γ-glutamyl)-lysine crosslink product could be useful biomarkers of kidney fibrosis and progression. Animal models: a rat 4-month 5/6th subtotal nephrectomy model of CKD and a rat 8-month streptozotocin model of diabetic kidney disease had 24-hour collection of urine, made using a metabolic cage, at regular periods throughout disease development. Patients: Urine samples from patients with CKD (n = 290) and healthy volunteers (n = 33) were collected prospectively, and progression tracked for 3 years. An estimated glomerular filtration rate (eGFR) loss of 2-5 mL/min/year was considered progressive, with rapid progression defined as > 5 mL/min/year. Assays: TG2 was measured in human and rat urine samples by enzyme-linked immunosorbent assay (ELISA) and ε-(γ-glutamyl)-lysine by exhaustive proteolytic digestion and amino acid analysis. Urinary TG2 and ε-(γ-glutamyl)-lysine increased with the development of fibrosis in both animal model systems. Urinary TG2 was 41-fold higher in patients with CKD than HVs, with levels elevated 17-fold by CKD stage 2. The urinary TG2:creatinine ratio (UTCR) was 9 ng/mmol in HV compared with 114 ng/mmol in non-progressive CKD, 1244 ng/mmol in progressive CKD and 1898 ng/mmol in rapidly progressive CKD. Both urinary TG2 and ε-(γ-glutamyl)-lysine were significantly associated with speed of progression in univariate logistic regression models. In a multivariate model adjusted for urinary TG2, ε-(γ-glutamyl)-lysine, age, sex, urinary albumin:creatinine ratio (UACR), urinary protein:creatinine ratio (UPCR), and CKD stage, only TG2 remained statistically significant. Receiver operating characteristic (ROC) curve analysis determined an 86.4% accuracy of prediction of progression for UTCR compared with 73.5% for UACR. Urinary TG2 and ε-(γ-glutamyl)-lysine are increased in CKD. In this pilot investigation, UTCR was a better predictor of progression in patients with CKD than UACR. Larger studies are now warranted to fully evaluate UTCR value in predicting patient outcomes.

The association between hepatitis C virus infection and renal function

BACKGROUND

The association between hepatitis C virus (HCV) infection and chronic kidney disease (CKD) still remains controversial. We aimed to investigate whether HCV really affects renal function, and to analyze the association between clinical effects of CHC and decreased kidney function (assessed by glomerular filtration rate (eGFR) level).

METHODS

An estimated 3360 patients with HCV infection and 3360 age- and sex-matched community-based control individuals without HCV were enrolled (1:1, case and control ratio) in this study between 2004 and 2016. We used the modification of diet in renal diseases to calculate eGFR. Demographic and laboratory parameters were assessed, and appropriate statistical methods were performed for the analysis.

RESULTS

Multivariate logistic regression analysis revealed that serum alanine aminotransferase level (odds ratio [OR] 0.998; 95% confidence interval [CI] 0.997-0.999; P = 0.001), platelet count (OR 0.997; 95% CI 0.995-0.999; p = 0.002), and hypertension (OR 1.31; 95% CI 1.03-1.66; P = 0.027) were significantly associated with HCV infection and serum triglyceride levels (OR 1.001; 95% CI 1.00-1.002; p = 0.005), platelet count (OR 0.996; 95% CI 0.995-0.997; p < 0.001), body mass index (BMI) >25 (OR 1.43; 95% CI 1.23-1.67; p < 0.001), hypertension (OR 1.69; 95% CI 1.42-1.99; p < 0.001), hyperlipidemia (OR 1.32; 95% CI 1.02-1.71; p = 0.035), and diabetes (OR 1.33; 95% CI 1.03-1.71; p = 0.032) were significantly associated with a low eGFR (<90 mL/min/m3) in control subjects. The BMI >25 kg/m2, hypertension, and diabetes were found to be associated with low eGFR interaction with the HCV infection, via a multivariate analysis.

CONCLUSION

Our study found that the patients with HCV infection are associated with a low eGFR compared with non-HCV-infected patients. This association is consistent in obese, diabetic, and hypertensive patients.

HCV cirrhotic patients treated with direct-acting antivirals: Detection of tubular dysfunction and resolution after viral clearance

BACKGROUND/AIMS

Hepatitis C virus (HCV) has been identified in tubular epithelial cells of infected patients; however, the presence of tubular dysfunction, which is a risk factor for chronic kidney disease (CKD), has never been examined in vivo. The present prospective longitudinal study aimed to estimate the prevalence of tubular dysfunction alone or with glomerular damage and its evolution after HCV clearance in cirrhotic patients.

METHODS

One hundred and thirty-five consecutive Child-Pugh A cirrhotic patients were evaluated before antiviral treatment and 6 months after the end of therapy. Tubular dysfunction was evaluated by urinary alpha1-microglobulin to creatinine ratio (α1-MCR), and glomerular damage was assessed by urinary albumin to creatinine ratio (ACR).

RESULTS

Almost all the patients (93.3%) showed a normal or mildly decreased e-GFR (KDIGO-G1/G2-categories). Tubular dysfunction was found in 23.7% (32/135) of patients, co-occurring with glomerular damage in 37.5% (12/32) of cases, while glomerular damage was found in 16.3% (22/135) of patients. In multiple logistic regression, glomerular damage and the concomitant presence of diabetes and hypertension were the only predictors significantly associated with tubular dysfunction. After HCV clearance, patients experienced a significant reduction of α1-MCR levels (21.0 vs 10.5 μg/mg, P = .009) and tubular dysfunction resolved in 57.1% of subjects.

CONCLUSIONS

Tubular dysfunction is an unrecognized feature of HCV-related kidney disease in cirrhotic patients and its presence should be primarily investigated in subjects with glomerular damage, diabetes and hypertension, despite normal e-GFR. Tubular dysfunction resolves in the majority of cases after HCV clearance; however, it may persist after antiviral treatment and further studies should evaluate its long-term impact on kidney function.

Hospitalization With Major Infection and Incidence of End-Stage Renal Disease: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

To evaluate whether the incidence of infectious diseases increases the long-term risk for incident end-stage renal disease (ESRD) in the general population.

PATIENTS AND METHODS

In 10,290 participants of the Atherosclerosis Risk in Communities Study who attended visit 4 (1996-1998), we evaluated the association of incident hospitalization with major infections (pneumonia, urinary tract infection, bloodstream infection, and cellulitis and osteomyelitis) with subsequent risk for ESRD through September 30, 2015. Hospitalization with major infection was entered into multivariable Cox models as a time-varying exposure to estimate the hazard ratios.

RESULTS

Mean age was 63 years, and of 10,290 individuals, 56% (n=5781) were women, 22% (n=2252) were black, and 7% (n=666) had an estimated glomerular filtration rate less than 60 mL/min/1.73 m2. During a median follow-up of 17.4 years, there were 2642 incident hospitalizations with major infection and 281 cases of ESRD (132 cases after hospitalization with major infection). The risk for ESRD was higher following major infection compared with while free of major infection (crude incidence rate, 10.9 vs 1.0 per 1000 person-years). In multivariable time-varying Cox analysis, hospitalization with major infection was associated with a 3.3-fold increased risk for ESRD (hazard ratio, 3.34; 95% CI, 2.56-4.37). The association was similar across pneumonia, urinary tract infection, bloodstream infection, and cellulitis and osteomyelitis, and remained significant across subgroups of age, sex, race, diabetes, history of cardiovascular disease, and chronic kidney disease.

CONCLUSION

Hospitalization with major infection was independently and robustly associated with subsequent risk for ESRD. Whether preventive approaches against infection have beneficial effects on kidney outcomes may deserve future investigations.

Hepatitis c virus and chronic kidney disease

INTRODUCTION

Hepatitis C virus (HCV) infection is associated with an increased incidence and progression of chronic kidney disease (CKD), as well as higher mortality in CKD and renal transplant patients. Direct acting antiviral agents (DAAs) have revolutionized the treatment of HCV, with viral eradication attained in 90-100% of treated patients. DAAs have an excellent safety and tolerability profile in CKD and renal transplant patients.

AREAS COVERED

In this review, we discuss the association of HCV with incidence and progression of CKD as well as its effect on outcomes and mortality. We also discuss the available treatment options in patients with CKD and renal transplant and in HCV-associated glomerular disease.

EXPERT OPINION

The availability of newly available direct acting anti-viral agents has revolutionized the treatment of HCV in persons with advanced CKD and undergoing dialysis. With these regimens, viral eradication can be attained in 90-100% of the treated patients. The safety, tolerability, and efficacy of these drugs in renal transplant patients have also made it possible to use HCV-infected grafts and successful virus eradication at a later stage.

Impact of Direct Acting Antiviral Agent Therapy upon Extrahepatic Manifestations of Hepatitis C Virus Infection

PURPOSE OF REVIEW

Direct acting antiviral agents (DAAs) have emerged as simple, short, safe, and effective treatments for chronic hepatitis C (CHC) infection. CHC is a systemic disease with frequent and multiple extrahepatic manifestations. The beneficial effects of DAA treatment regimens extend beyond improvement in liver-related outcomes to amelioration of extra hepatic manifestations and are likely to have economic implications. The purpose of this review is to evaluate the effect of DAAs on extra hepatic manifestations of CHC virus infection.

RECENT FINDINGS

Recent studies indicate that DAAs are associated with reduction in all-cause mortality, even in patients without significant hepatic fibrosis. They are also associated with reduction in incident cardiovascular disease and diabetes. DAAs are the mainstay of treatment in HCV-associated cryoglobulinemia and lymphoma. Successful HCV therapy with DAAs also improves patient-related outcomes such as health-related quality of life. DAAs improve extrahepatic manifestations of CHC virus infection. Future studies are needed to evaluate the long-term durability of treatment response and for accounting amelioration of extrahepatic manifestations into the cost effectiveness of DAA regimens.

Direct-acting antiviral therapy slows kidney function decline in patients with Hepatitis C virus infection and chronic kidney disease

Hepatitis C virus (HCV) infection is common and can accelerate chronic kidney disease (CKD) progression. Direct-acting antiviral (DAA) therapies against hepatitis C have consistently shown rates of sustained viral remission. However, the effect on kidney function is unknown. In a retrospective observational cohort study of HCV-infected patients receiving DAA therapies from 2013 to 2017, the slopes of estimated glomerular filtration rate (eGFR) decline were compared in the three years before DAA therapy to the slope after therapy. Pre- and post-treatment albuminuria values were also compared. In all, 1,178 patients were included; mean age of 56, 64% male, 71% white, 21% were diabetic, and 42% with cirrhosis. In patients with eGFR less than 60ml/min per 1.73m2, the annual decline in eGFR in the three years prior to treatment was -5.98 ml/min per year (95% confidence interval -7.30 to -4.67) and improved to -1.32 ml/min per year (95% confidence interval -4.50 to 1.88) after DAA therapy. In patients with eGFR greater than 60ml/min per 1.73m2 the annual decline in eGFR in the three years prior to treatment was -1.43 ml/min per year (95% confidence interval -1.78 to -1.08) and after DAA therapy was -2.32 ml/min per year (95% confidence interval -3.36 to -1.03). Albuminuria improved significantly in patients without diabetes, but not in those with diabetes. Predictors of eGFR improvement included having CKD at baseline and being non-diabetic. Events of acute kidney injury were rare, occurring in 29 patients, and unrelated to antiviral therapy in 76% of cases. Thus, DAA therapy for HCVs infection may slow CKD progression.

Association Between Hepatitis C Virus and Chronic Kidney Disease: A Systematic Review and Meta-Analysis

INTRODUCTION AND AIM

The role of hepatitis C virus infection as a risk factor for the development and progression of chronic kidney disease in the general population remains unclear.

MATERIAL AND METHODS

A systematic review of the published medical literature was performed to assess whether positive anti-HCV serologic status is associated with higher frequency of chronic kidney disease in the adult general population. We used a random-effects model to generate a summary estimate of the relative risk of chronic kidney disease (defined by lowered glomerular filtration rate or detectable proteinuria) with HCV across the published studies. Meta-regression and stratified analysis were also carried out.

RESULTS

Forty studies were eligible (n = 4,072,867 patients), and separate meta-analyses were conducted according to the outcome. Pooling results of longitudinal studies (n = 15 studies, n = 2,299,134 unique patients) demonstrated an association between positive anti-HCV serologic status and increased incidence of CKD, the summary estimate for adjusted HR with HCV across the surveys, 1.54 (95% CI, 1.26; 1.87) (P &lt; 0.001). Between-study heterogeneity was observed (Q value by Chi-squared [χ2] test 500.3, P &lt; 0.0001). The risk of chronic kidney disease related to HCV, in the subset of surveys from Asia was 1.45 (1.27; 1.65) (P &lt; 0.001) (no heterogeneity). According to our meta-regression, ageing (P &lt; 0.0001) and duration of follow-up (P &lt; 0.0001) increased the risk of chronic kidney disease among HCV-positive subjects. We observed a relationship between anti-HCV positive serologic status and frequency of proteinuria, adjusted effect estimate of proteinuria with HCV among surveys was 1.633 (95% CI, 1,29; 2.05) (P &lt; 0.001) (n = 10 studies; 315,404 unique patients). However, between-studies heterogeneity was noted (P value by Q test &lt; 0.0001).

CONCLUSION

An association between HCV infection and increased risk of chronic kidney disease in the general population exists. The mechanisms underlying such association are currently under active investigation.

Transmission of hepatitis C virus in the dialysis setting and strategies for its prevention

Hepatitis C virus (HCV) infection is more common among hemodialysis patients than the general population and transmission of HCV in dialysis clinics has been reported. In the context of the increased morbidity and mortality associated with HCV infection in the end stage renal disease population, it is important that dialysis clinics have processes in place for ensuring recommended infection control practices, including Standard Precautions, through regular audits and training of the staff. This review will summarize the epidemiology of HCV infection and risk factors for HCV transmission among hemodialysis patients. In addition, the proper protocols are required to investigate suspected cases of HCV transmission in dialysis facilities and recommendations for prevention of HCV transmission in will be reviewed.

Considering hepatitis C virus infection as a systemic disease

Hepatitis C virus (HCV) infection has been demonstrated to result in several adverse hepatic outcomes and has been associated with a number of important extrahepatic manifestations. The scope of extrahepatic clinical possibilities includes systemic diseases such as vasculitis and lymphoproliferative disorders, cardiovascular disease, myalgia, arthritis, and sicca syndrome. These end-organ effects of HCV may dominate the clinical course beyond the hepatic complications and significantly worsen the long-term prognosis of infected patients. Until several years ago, the standard of care for the treatment of HCV infection had been interferon-alpha-based regimens, which not only had limited effectiveness in achieving a cure but were often poorly tolerated, especially in patients with kidney disease. In those HCV-infected patients with significant systemic manifestations, the interferon-based regimens were problematic given their association with a wide variety of toxicities. The development of highly effective direct-acting antiviral agents to treat HCV infection presented an opportunity to improve the HCV care cascade with the eradication of HCV in most infected patients and by reducing the burden of both hepatic and extrahepatic complications.

The association of hepatitis C infection with the onset of CKD and progression into ESRD

Hepatitis C virus (HCV) infection is not only an important cause of chronic liver disease, but extrahepatic manifestations are common and include chronic kidney disease (CKD). HCV is classically associated with cryoglobulinemic glomerulonephritis in the context of mixed cryoglobulinemia syndrome, but other glomerular diseases also occur and may be significantly under-recognized. HCV may cause glomerular disease by immune complex deposition; however, other potential mechanisms by which HCV promotes CKD include a direct cytopathic effect of the virus on renal tissue, and by its association with accelerated atherosclerosis, insulin resistance, and chronic inflammation. Epidemiologic studies show HCV infection confers an increased risk of incident CKD and accelerates progression of CKD to end-stage renal disease (ESRD) in the general population, as well as subpopulations including diabetic patients, those coinfected with human immunodeficiency virus (HIV), and kidney transplant recipients. Patients with CKD and HCV infection experience inferior clinical outcomes, including poorer quality of life and an increased risk of mortality. Treatment with interferon-based regimens is associated with decreased risk of incident CKD and ESRD, though prior studies are limited by the small number of patients with HCV and CKD who underwent treatment. With the advent of new, well-tolerated direct-acting antiviral combinations that are not cleared by the kidneys, it is possible to treat all genotypes of HCV infection in patients with CKD and ESRD. More data on the effect of direct-acting antivirals on CKD incidence and progression are necessary. However, there is every expectation that with improved access to HCV treatment, the burden of CKD in patients with HCV could significantly decline.

Hepatitis C virus infection in chronic kidney disease: paradigm shift in management

Hepatitis C virus (HCV) infection in chronic kidney disease (CKD) is associated with increased liver-related morbidity and mortality rates, accelerated progression to end-stage renal disease, and risk of cardiovascular events. CKD patients with HCV infection require antiviral therapy. Pegylated interferon (peg-IFN) plus ribavirin was the standard of care for HCV-infected CKD patients before the introduction of first-generation direct-acting antiviral (DAA) oral anti-HCV agents. Peg-IFN-based treatment has a low virologic response rate and poor compliance, resulting in a high dropout rate. Recently, several clinical trials of all-DAA combination regimens have reported excellent antiviral efficacy and few adverse drug reactions in HCV-infected patients with CKD. These positive results have revolutionized the treatment of chronic HCV infection in this population. In this review, we address the impact of chronic HCV infection in CKD patients, and discuss their management using next-generation DAAs.

'Care and Prevent': rationale for investigating skin and soft tissue infections and AA amyloidosis among people who inject drugs in London

BACKGROUND

Skin and soft tissue infections (SSTIs) are a leading cause of morbidity and mortality among people who inject drugs (PWID). International data indicate up to one third of PWID have experienced an SSTI within the past month. Complications include sepsis, endocarditis and amyloid A (AA) amyloidosis. AA amyloidosis is a serious sequela of chronic SSTI among PWID. Though there is a paucity of literature reporting on AA amyloidosis among PWID, what has been published suggests there is likely a causal relationship between AA amyloidosis and injecting-related SSTI. If left untreated, AA amyloidosis can lead to renal failure; premature mortality among diagnosed PWID is high. Early intervention may reverse disease. Despite the high societal and individual burden of SSTI among PWID, empirical evidence on the barriers and facilitators to injecting-related SSTI prevention and care or the feasibility and acceptability of AA amyloidosis screening and treatment referral are limited. This study aims to fill these gaps and assess the prevalence of AA amyloidosis among PWID.

METHODS

Care and Prevent is a UK National Institute for Health Research-funded mixed-methods study. In five phases (P1-P5), we aim to assess the evidence for AA amyloidosis among PWID (P1); assess the feasibility of AA amyloidosis screening, diagnostic and treatment referral among PWID in London (P2); investigate the barriers and facilitators to AA amyloidosis care (P3); explore SSTI protection and risk (P4); and co-create harm reduction resources with the affected community (P5). This paper describes the conceptual framework, methodological design and proposed analysis for the mixed-methods multi-phase study.

RESULTS

We are implementing the Care and Prevent protocol in London. The systematic review component of the study has been completed and published. Care and Prevent will generate an estimate of AA amyloidosis prevalence among community recruited PWID in London, with implications for the development of screening recommendations and intervention implementation. We aim to recruit 400 PWID from drug treatment services in London, UK.

CONCLUSIONS

Care and Prevent is the first study to assess screening feasibility and the prevalence of positive proteinuria, as a marker for AA amyloidosis, among PWID accessing drug treatment services. AA amyloidosis is a serious, yet under-recognised condition for which early intervention is available but not employed.

Treatment of early stage chronic hepatitis C virus infection

INTRODUCTION

Treatment of Hepatitis C Virus (HCV) with direct acting antivirals (DAAs) is able to achieve the cure of infection in almost the totality of patients, independently of the characteristics of the individual and the virus, using short treatment schedules, and without the need of ribavirin. The high cost of DAAs is the main limiting factor for universal treatment of HCV. However, there is a strong evidence that treatment of infection at the early stage of disease may be the most rewarding approach. Areas covered: This review evaluates the aspects underlying the benefit of treating chronic HCV infection at the early stage of disease. It outlines the considerations that have to be taken into account when planning treatment in patients with HCV and minimal liver disease, assessing the positive reflex of viral eradication on several HCV-associated extra-hepatic conditions such as the risk of lymphoma, insulin-resistance and glycaemic control, and renal function. Lastly, it also covers the improvement of patients' quality of life and the pharmaco-economic aspects associated with early treatment. Expert commentary: Treatment of patients with HCV and minimal liver disease is associated with a beneficial, pleiotropic effect of viral eradication that goes beyond the simplistic consideration of the improvement in liver disease-related outcomes.

A systematic review and meta-analysis: Does hepatitis C virus infection predispose to the development of chronic kidney disease?

We aimed to meta-analytically assess the predisposition of hepatitis C virus (HCV) infection to the occurrence and severity of chronic kidney disease (CKD). Two authors independently searched articles and abstracted information. Odds ratio (OR) or hazard ratio (HR) along with 95% confidence interval (CI) was converged separately in 12 longitudinal (1,972,044 subjects) and 15 cross-sectional (937,607 subjects) studies. Overall effect estimate was remarkably significant in longitudinal studies (HR, 95% CI, P: 1.45, 1.23-1.71, < 0.001), in contrast to that in cross-sectional studies (OR, 95% CI, P: 1.25, 0.90-1.73, 0.188), with obvious heterogeneity (I² > 95%). HCV infection was also associated with an 1.54-fold (95% CI, P: 1.27-1.87, < 0.001) increased risk of having prevalent proteinuria. In longitudinal studies with estimated glomerular filtration rate (eGFR) < 60, < 30 and < 15 ml/min/1.73m², the corresponding HR was 1.39 (95% CI, P: 1.14-1.69, 0.001), 1.79 (0.91-3.51, 0.091) and 2.30 (1.26-4.19, 0.007). Further grouping the longitudinal studies by median follow-up time at 5 years revealed that the effect estimate was reinforced in long-term studies (HR, 95% CI, P: 1.86, 1.19-2.89, 0.006; I²=98.1%) relative to that in short-term studies (1.21, 1.03-1.43, 0.024; 92.0%). In conclusion, our findings demonstrate the significant risk of experiencing incident CKD after HCV infection, with the lower eGFR and longer HCV exposure time entailing a greater risk.

Confluence of Epidemics of Hepatitis C, Diabetes, Obesity, and Chronic Kidney Disease in the United States Population

BACKGROUND & AIMS

Obesity, kidney disease, and diabetes are common conditions that can affect outcomes of patients with chronic hepatitis C. The authors aimed to quantify the burden of these comorbid conditions among adults with chronic hepatitis C in the United States and to estimate the risk of death among people with chronic hepatitis C and comorbidities.

METHODS

The authors conducted cross-sectional and prospective analyses of 13,726 participants in the third National Health and Nutrition Examination Survey (NHANES III) and 23,691 participants of NHANES 1999-2012. Serum samples were analyzed for the presence of antibodies to hepatitis C virus (anti-HCV); in samples found to be positive for anti-HCV, the authors quantified HCV RNA (viral load). Individuals with anti-HCV and detectable HCV RNA were considered to have chronic hepatitis C. Comorbidities were defined using self-reported, physical examination, and laboratory data, as available. The authors used logistic models and predictive margins to estimate the adjusted prevalence of comorbidities in patients with chronic hepatitis C. The authors used Poisson regression models to estimate adjusted mortality rates based on chronic hepatitis C status, with or without comorbidities. Cox proportional hazards regression models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause, cardiovascular, and cancer mortality according to chronic hepatitis C status, with and without comorbidities.

RESULTS

Among persons with chronic hepatitis C, the demographic-adjusted prevalence estimate of diabetes was 17.9% (95% CI, 11.2%-27.5%) and of obesity was 20.9% (95% CI, 12.4%-29.5%). Overall, 69.6% of persons with chronic hepatitis C had at least 1 major cardiometabolic comorbidity (95% CI, 62.1%-76.2%). Only 38% of adults with chronic hepatitis C reported a diagnosis of liver disease. Chronic hepatitis C was associated with a substantially increased risk of death (HR, 2.45), especially in the presence of diabetes (HR, 3.24) or chronic kidney disease (HR, 4.39).

CONCLUSION

In an analysis of NHANES data, the authors found that individuals with chronic hepatitis C have a high burden of major cardiometabolic comorbidities. Diabetes and chronic kidney disease, in particular, are associated with substantial excess mortality in persons with chronic hepatitis C.

Hepatitis C and Its Metabolic Complications in Kidney Disease

INTRODUCTION

Evidence has been accumulated during the last decade showing that HCV infection plays an important activity at hepatic and extra-hepatic level. Chronic HCV is associated with a large spectrum of extra-hepatic manifestations including lympho-proliferative diseases and metabolic abnormalities (such as insulin resistance and fatty liver disease).

MATERIAL AND METHODS

We have performed an extensive review of the medical literature regarding the increased risk of cardiovascular and kidney disease that has been observed in various groups of HCV-infected patients. The potential link between such increased risk and the metabolic consequences of chronic HCV infection has been explored.

RESULTS

According to a systematic review with a meta-analysis of longitudinal studies (n = 9 clinical observational studies; n = 1,947,034 unique patients), we found a strong relationship between positive anti-HCV serologic status and increased incidence of chronic kidney disease in the adult general population, the summary estimate for adjusted hazard ratio was 1.43 (95% confidence intervals, 1.23; 1.63, P = 0.0001) (random-effects model) in anti-HCV positive patients. In another meta-analysis of clinical observational studies (n = 145,608 unique patients on long term dialysis; n = 14 observational studies), anti-HCV sero-positive status was an independent and significant risk factor for death in patients on maintenance dialysis. The summary estimate for adjusted relative risk (all-cause mortality) was 1.35 with a 95% confidence interval (CI) of 1.25; 1.47 (P &lt; 0.01) in anti-HCV positive patients on maintenance dialysis. An updated and stratified analysis (n = 4 studies, n = 91,916 patients on maintenance dialysis) resulted in an adjusted HR for cardiovascular mortality among anti-HCV positive patients of 1.21 (95% CI, 1.06; 1.39) (P &lt; 0.01); the homogeneity assumption was not rejected. The mechanisms underlying such relationships remain unclear; it has been suggested that HCV promotes atherogenesis through direct and indirect mechanisms.

CONCLUSIONS

Clinical trials are under way to assess whether the clearance of HCV RNA from serum by direct-acting antiviral drugs reduces all cause or disease-specific (cardiovascular) mortality among patients on maintenance dialysis.

Effect of Sofosbuvir-Based Hepatitis C Virus Therapy on Kidney Function in Patients with CKD

BACKGROUND AND OBJECTIVES

Hepatitis C virus infection is common in patients with CKD and leads to accelerated progression to ESRD. Sofosbuvir is a potent direct-acting antiviral therapy against hepatitis C virus; however, there are concerns about its safety in patients with CKD. The objective of our study was to determine the safety and efficacy of sofosbuvir in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied a retrospective observational cohort of patients with CKD defined by eGFR<60 ml/min per 1.73 m2, ≥30 mg albuminuria per 1 g creatinine, or ≥200 mg proteinuria per 1 g creatinine who received sofosbuvir-based therapy in a large health care system. Regression models were constructed to predict likelihood of sustained virologic response, detect adverse events, and examine changes in eGFR from baseline to follow-up.

RESULTS

Ninety-eight patients with CKD (42% stage 1 or 2 CKD and 58% stage 3 CKD) were included. Mean age was 62 years old, 78% were men, and 65% were white. Additionally, 49% of patients had diabetes, 38% of patients had cirrhosis, and 33% of patients had prior solid organ transplant. Overall sustained virologic response was 81% and varied by regimen used and viral genotype. Average baseline eGFR was equivalent to average on-treatment eGFR, but seven patients experienced a rise in creatinine ≥1.5 times baseline while taking sofosbuvir; all but one recovered. In patients with eGFR<60 ml/min per 1.73 m2 at baseline (stage 3 CKD), regression models showed that hepatitis C cure was associated with a 9.3 (95% confidence interval, 0.44 to 18) ml/min per 1.73 m2 improvement in eGFR during the 6-month post-treatment follow-up period. Adverse events were common (81%), but serious adverse events (17%) and treatment discontinuations (8%) were uncommon.

CONCLUSIONS

Sofosbuvir-based direct-acting antiviral therapy is safe and effective in a cohort of patients with CKD infected with hepatitis C.

Do we really need more evidence to use hepatitis C positive donor kidney more liberally?

The number of patients listed active for kidney transplantation has continued to rise over the last 10 years, leading to significantly increased wait-list time for patients awaiting kidney transplantation in the USA. This increased demand has led to a supply–demand mismatch and should prompt clinicians to seek timely solutions to improve access to available organs. Hepatitis C virus positive [HCV(+)] kidneys continue to be discarded without clear evidence that they lead to poor outcomes in the current era of highly efficacious HCV treatment with direct-acting antiviral agents (DAAs). Increased utilization of HCV(+) donor kidneys will decrease wait-list time and improve availability of donor organs. Emerging data suggests that HCV can be successfully treated with DAAs after kidney transplantation with 100% sustained virologic response rates and no significant changes from baseline kidney function. Utilization of HCV(+) donor kidneys should be considered more liberally in the era of highly effective HCV treatment. Further studies are warranted to assess the long-term effect of HCV(+) donor kidneys in transplant recipients in the new era of DAAs.

Chronic hepatitis C and chronic kidney disease: Advances, limitations and unchartered territories

Over the past few years, treatment options for chronic hepatitis C virus (HCV) infection have evolved dramatically. The current approved interferon-free direct-acting antiviral (DAA) regimens have been shown to be safe and effective with sustained virologic response (SVR) rates of >90% in most patients. Unique issues yet remain such as the challenges in patients with impaired renal function or decompensated cirrhosis. Patients with stages 4-5 chronic kidney disease (CKD) have a higher prevalence of HCV infection compared with the general population. Chronic HCV in those on dialysis and in kidney transplant recipients is associated with higher morbidity and mortality than uninfected patients. The HCV-infected population is also at risk of developing extrahepatic manifestations associated with altered immune system function and chronic inflammation with cryoglobulinaemic vasculitis being the most common of these manifestations. Therefore, patients with CKD stages 4-5 have to be considered priority patients for HCV therapy. New antiviral therapies have the potential to improve outcomes in this vulnerable patient population, including those on haemodialysis. Recently published studies conducted in kidney transplant recipients have demonstrated successful outcomes. It is thus essential that we carefully select the most appropriate DAA regimen and the best time for treatment in the context of kidney transplantation or cryoglobulinaemic vasculitis. While sofosbuvir, the only approved nucleotide NS5B inhibitor, has been the backbone of most pangenotypic therapeutic regimens, it has a limitation in those with advanced kidney disease. The currently approved regimens for those with stage 4/5 CKD, while effective, have challenges in that they apply to genotype 1/4 and may require RBV for genotype 1a. Globally, genotype 3 is a common infection, and thus, this group with CKD presents a huge unmet need for effective therapies. As therapy of HCV in renal transplant recipients has been highly successful, it provides an opportunity to expand the use of HCV-infected organs in solid organ transplantation.

New insights into HCV-related rheumatologic disorders: A review

Hepatitis C virus (HCV) infected patients are known to be exposed to major liver complications i.e. cirrhosis and hepatocellular carcinoma. In addition, many extrahepatic manifestations including rheumatologic disorders have been reported in up to two-third of HCV infected patients. These manifestations include frank auto-immune and rheumatic diseases (such as arthralgia, myalgia, arthritis, sicca syndrome and vasculitis) which may dominate the course of infection. Until recently, the standard of care of HCV has been the use of interferon-alpha based regimens, which not only had limited effectiveness in HCV cure but were poorly tolerated. In patients with rheumatic diseases interferon-based regimens may be problematic given their association with a wide variety of autoimmune toxicities. Recent therapeutic advances with new direct anti-HCV therapies (interferon-free) which are more effective and better tolerated, make screening for this comorbidity in patients with rheumatic disorders more important than ever. This review aimed to outline main HCV extrahepatic with a special focus on rheumatologic manifestations.

Hepatitis C Therapy in Renal Patients: Who, How, When?

Renal patients are overexposed to hepatitis C virus (HCV) infection. Hepatitis C virus infection may induce renal disease, i.e., cryoglobulinemic membrano-proliferative glomerulopathy and non-cryoglobulinemic nephropathy. Hepatitis C virus impacts general outcomes in chronic kidney disease, dialysis or transplanted patients. Hepatitis C virus infection is now about to be only part of their medical history thanks to new direct acting antiviral drugs exhibiting as much as over 95% of sustained virological response. All HCV-infected patients potentially can receive the treatment. Control of the virus is associated with better outcomes in all cases, whatever the severity of the hepatic or renal disease. This article focuses on HCV-induced renal diseases, the reciprocal impact of HCV infection on the renal outcome and renal status in liver disease, use of new direct-acting antiviral drugs with dosage adaptations and the most recent safety data.

Prevalence of Renal Impairment and Associated Conditions Among HCV-Infected Persons in the Chronic Hepatitis Cohort Study (CHeCS)

BACKGROUND

Guidelines for the treatment of HCV-infected persons were updated in August 2015 with new recommendations for patients with renal impairment. Treatment is imperative for patients with severe, renal-associated extrahepatic manifestations of HCV infection.

AIMS

We sought to describe the prevalence of these conditions among current HCV-infected patients in a population-based prospective, observational cohort study at four large US health systems.

METHODS

Data from cohort patients with chronic HCV infection during 2012 were analyzed for the period from 2006 to 2013. We determined the prevalence of mild to moderately impaired renal function defined as having the most recent estimated glomerular filtration rate [eGFR] ≤ 80 ml/min/1.73 m(2), with severe impairment defined as eGFR < 30 ml/min/1.73 m(2), based on the treatment guidelines. Prevalence of extrahepatic conditions was ascertained using ICD9-codes.

RESULTS

Among 5772 persons, the prevalence of eGFR ≤ 80 was 33 % and eGFR < 30 was 2 %, including among patients with hepatic fibrosis. Diagnosed extrahepatic renal manifestations were rare: vasculitis- 0.2 %, nephrotic syndrome- 0.3 %, and cryoglobulinemia- 0.9 %.

CONCLUSIONS

While the prevalence of severe renal impairment and diagnosed extrahepatic manifestations was low, mild-to-moderate renal impairment was common in HCV patients, including those with advanced liver fibrosis for whom the need for treatment is urgent.

Extrahepatic manifestations of chronic hepatitis C virus infection

During hepatitis C virus (HCV) chronic infection, extrahepatic manifestations are frequent and polymorphous. This article reports on a large cohort of patients with HCV-related autoimmune or lymphoproliferative disorders, from mixed cryoglobulinemia vasculitis to frank lymphomas. The relationship between HCV infection and such immune-related diseases has been formally demonstrated by epidemiological, clinical, immunological and pathological data, and results of therapeutic trials. More recently, other nonliver-related HCV disorders have been reported, including cardiovascular (i.e. stroke, ischemic heart disease), renal, metabolic and central nervous system diseases. For these manifestations, most evidence comes from large epidemiological studies; there is a need for mechanistic studies and therapeutic trials for confirmation. Beyond the risk of developing liver complications, that is, cirrhosis and liver cancer, patients with HCV infection have an increased risk of morbidity and mortality related to nonliver diseases. HCV chronic infection should be analyzed as a systemic disease in which extrahepatic consequences increase the weight of its pathological burden. The need for effective viral eradication measures is underlined.

Extrahepatic manifestations in chronic hepatitis C virus carriers

Patients with chronic hepatitis C virus (HCV) infection frequently present with extrahepatic manifestations covering a large spectrum, involving different organ systems leading to the concept of systemic HCV infection. These manifestations include autoimmune phenomena and frank autoimmune and/or rheumatic diseases and may dominate the course of chronic HCV infection. Chronic HCV infection causes liver inflammation affecting the development of hepatic diseases. HCV is also a lymphotropic virus that triggers B cells and promotes favorable conditions for B lymphocyte proliferation, including mixed cryoglobulinemia (MC) and MC vasculitis, which is the most prominent extrahepatic manifestation of chronic HCV infection. HCV may also promote a low-grade chronic systemic inflammation that may affect the development of some extrahepatic manifestations, particularly cardiovascular and cerebral vascular diseases. Recognition of extrahepatic symptoms of HCV infection could facilitate early diagnosis and treatment. The development of direct-acting antiviral agents (DDAs) has revolutionized HCV treatment. DDAs, as well as new B-cell-depleting or B-cell-modulating monoclonal antibodies, will expand the panorama of treatment options for HCV-related extrahepatic manifestations including cryoglobulinemic vasculitis. In this context, a proactive, integrated approach to HCV therapy should maximize the benefits of HCV therapy, even when liver disease is mild.

Hepatitis C Virus Infection Increases the Risk of Developing Chronic Kidney Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND RATIONALE

Chronic kidney disease and hepatitis C virus are prevalent in the general population worldwide, and controversy exists about the impact of HCV infection on the development and progression of kidney disease.

DESIGN

A systematic review of the published medical literature was made to assess whether positive anti-HCV serologic status plays an independent impact on the development of chronic kidney disease in the adult general population. We used a random-effects model to generate a summary estimate of the relative risk of chronic kidney disease (defined by reduced glomerular filtration rate or detectable proteinuria) with HCV across the published studies. Meta-regression and stratified analysis were also conducted.

RESULTS

Twenty-three studies (n = 2,842,421 patients) were eligible, and separate meta-analyses were performed according to the outcome. Pooling results of longitudinal studies (n = 9; 1,947,034 unique patients) demonstrated a relationship between positive HCV serologic status and increased incidence of chronic kidney disease, the summary estimate for adjusted hazard ratio was 1.43 (95% confidence interval 1.23; 1.63, P = 0.0001), and between-studies heterogeneity was noted (P value by Q test <0.0001). The risk of the incidence of chronic kidney disease associated with HCV, in the subset of Asian surveys, was 1.31 (95% confidence interval 1.16; 1.45) without heterogeneity (P value by Q test = 0.6). HCV positive serology was an independent risk factor for proteinuria; adjusted odds ratio, 1.508 (95% confidence intervals 1.19; 1.89, P = 0.0001) (n = 6 studies; 107,356 unique patients).

CONCLUSIONS

HCV infection is associated with an increased risk of developing chronic kidney disease in the adult general population.

Association of Hepatitis C Virus Infection with Proteinuria and Glomerular Filtration Rate

AIM

Despite several studies, the extent to which hepatitis C virus (HCV) infection is associated with chronic kidney disease (CKD) remains controversial. Thus, we examined the relationship between HCV and CKD using the continuous National Health and Nutrition Examination Survey (1999-2012).

METHODS

Specimens positive for anti-HCV antibodies were retested and confirmed with recombinant immunoblot assay (RIBA). Proteinuria was defined as urine albumin creatinine ratio > 30 mg/g. CKD was defined as estimated glomerular filtration rate (GFR) < 60 mL/min/1.73 m(2) . We used linear and logistic regression models to examine the association between HCV and outcomes with and without adjustment for age, sex, race, hypertension, diabetes mellitus, and body mass index and accounting for the complex survey design.

RESULTS

Of the 33,729 eligible participants, HCV infection was present in 659 (1.73%). In unadjusted and adjusted analyses, HCV was associated with proteinuria (OR = 1.40, p = 0.01 and OR = 1.50, p = 0.02, respectively). In both unadjusted and adjusted analyses, individuals with HCV had significantly higher GFR than individuals without (1.4 mL/min, p = 0.04 and 2.7 mL/min, p < 0.001, respectively). We did not find an association of HCV with CKD in adjusted or unadjusted analyses.

CONCLUSION

HCV infection is associated with proteinuria and high GFR but not with CKD. The biological mechanism of the observed association needs further study.

Epidemiology, clinical characteristics, and management of chronic kidney disease in human immunodeficiency virus-infected patients

Antiretroviral therapy has markedly reduced acquired immune deficiency syndrome-related deaths and opportunistic infectious diseases. This has resulted in prolonged survival of individuals infected with the human immunodeficiency virus (HIV). However, this improvement in survival has been accompanied by an increase in the incidence of chronic kidney disease (CKD) and end-stage renal disease. CKD is now epidemic among HIV-infected populations in both Western and Eastern countries. Risk factors associated with CKD in HIV-infected populations include aging, hypertension, diabetes mellitus, co-infection with hepatitis C virus, a low CD4 cell count, and a high HIV viral load. Clinical experience has shown that HIV-infected individuals often have one or more concurrent risk factors for CKD. The cumulative effect of multiple risk factors on the development of CKD should be noted in this population. Glomerular disease directly related to HIV infection, so-called HIV-associated nephropathy, remains an important cause of CKD among a limited HIV population of African descent, but is less likely to be common among other urban HIV populations. The impact of exposure to nephrotoxic antiretroviral agents on the development of kidney disease is both an old and a new concern. In particular, the association of tenofovir with kidney tubular injury has been an area of great interest. The findings regarding tenofovir's adverse effect on long-term kidney function vary among studies. The early identification and treatment of CKD is recommended for reducing the burden of patients requiring dialysis in HIV-infected populations. Periodic monitoring of urinary concentrations of albumin, protein, and tubular injury markers such as low-molecular-weight proteins may be useful for the early diagnosis of patients at risk for incident CKD. This review focuses on recent epidemiology, clinical characteristics, and management of CKD in a contemporary HIV-infected population.

Association of hepatitis C viral infection with incidence and progression of chronic kidney disease in a large cohort of US veterans

An estimated 4 million Americans have been exposed to the hepatitis C virus (HCV). The risks of incident and progressive chronic kidney disease and of mortality in patients with normal kidney function infected with HCV are unclear. In a nationally representative cohort of 100,518 HCV(+) and 920,531 HCV(-) US veterans with normal baseline estimated glomerular filtration rate (eGFR), we examined the association of HCV infection with (1) all-cause mortality, (2) incidence of decreased kidney function (defined as eGFR <60 mL/min/1.73 m(2) and 25% decrease in eGFR), (3) end-stage renal disease, and (4) rate of kidney function decline. Associations were examined in naive and adjusted Cox models (for time-to-event analyses) and logistic regression models (for slopes), with sequential adjustments for important confounders. Propensity-matched cohort analysis was used in sensitivity analyses. The patients' age was 54.5 ± 13.1 (mean ± standard deviation) years, 22% were black, 92% were male, and the baseline eGFR was 88 ± 16 mL/min/1.73 m(2) . In multivariable adjusted models HCV infection was associated with a 2.2-fold higher mortality (fully adjusted hazard ratio = 2.17, 95% confidence interval [CI] 2.13-2.21), a 15% higher incidence of decreased kidney function (adjusted hazard ratio = 1.15, 95% CI 1.12-1.17), a 22% higher risk of steeper slopes of eGFR (adjusted odds ratio = 1.22, 95% CI 1.19-1.26), and a 98% higher hazard of end-stage renal disease (adjusted hazard ratio = 1.98, 95% CI 1.81-2.16). Quantitatively similar results were found in propensity-matched cohort analyses.

CONCLUSIONS

Infection with HCV is associated with higher mortality risk, incidence of decreased kidney function, and progressive loss of kidney function; randomized controlled trials are warranted to determine whether treatment of HCV infection can prevent the development and progression of chronic kidney disease and improve patient outcomes.

Extrahepatic manifestations of chronic hepatitis C virus infection

Hepatitis C virus (HCV) infected patients are known to be at risk of developing liver complications i.e. cirrhosis and liver cancer. However, the risks of morbidity and mortality are underestimated because they do not take into account non-liver consequences of chronic hepatitis C virus infection. Numerous extrahepatic manifestations have been reported in up to 74% of patients, from perceived to disabling conditions. The majority of data concern hepatitis C virus-related autoimmune and/or lymphoproliferative disorders, from mixed cryoglobulinaemia vasculitis to frank lymphomas. More recently, other hepatitis C virus-associated disorders have been reported including cardiovascular, renal, metabolic, and central nervous system diseases. This review aims to outline most of the extrahepatic manifestations that are currently being investigated, including some of autoimmune and/or lymphoproliferative nature, and others in which the role of immune mechanisms appears less clear. Beyond the liver, hepatitis C virus chronic infection should be analyzed as a multifaceted systemic disease leading to heavy direct and indirect costs. The accurate consideration of extrahepatic consequences of such a systemic infection significantly increases the weight of its pathological burden. The need for effective viral eradication measures is underlined.

Age and gender differences in the relationship between hepatitis C infection and all stages of Chronic kidney disease

Chronic kidney disease (CKD) is a worldwide health issue with heavy economic burden. Chronic hepatitis C virus (HCV) infection is a common cause of CKD, which can significantly impact the progression and mortality among patients with CKD. The prevalence of both illnesses is high in Taiwan. A multicentre and population-based cross-sectional study including 24 642 subjects was conducted to explore the association of HCV infection with the prevalence and severity of CKD. The measurements of metabolic parameters, eGFR and CKD stages were compared between subjects with HCV seropositivity and seronegativity. The analyses of association between HCV infection with CKD stages and evaluation of potential risk factors of CKD were performed by gender and age (≤ and >45 years). HCV-seropositive subjects accounted for 6.9% and had a significantly older age. The prevalence of CKD increased in those with HCV seropositivity (16.5%). Significantly higher prevalence of CKD stages ≥3 in HCV-seropositive subjects was noticed (7.8%). Age (>45 year), male gender, alcohol drinking, hypertension, creatinine and HCV infection were the significant factors associated with the presence of CKD. HCV seropositivity was an independent risk factor of developing CKD and associated with an increased risk of having CKD of all stages. The higher prevalence of earlier stage of CKD warrants longitudinal studies with frequent testing on renal function and sufficient duration to determine the changes of eGFR over time. Implementation of effective treatment intervention is also required for these subjects to prevent the progression of CKD to late stages.

Hepatitis C virus infection, mixed cryoglobulinemia, and kidney disease

Hepatitis C virus (HCV) may instigate mixed cryoglobulinemia; the most significant accompanying kidney lesion is type I membranoproliferative glomerulonephritis, usually occurring in the context of type II mixed cryoglobulinemia. Additionally, recent data support a link between HCV infection and proteinuria in population-based studies, raising the possibility that kidney diseases associated with HCV may be more common than previously thought. A number of strategies have been used to treat HCV-related glomerulonephritis, including antiviral agents, immunosuppressive therapies such as corticosteroids and cytotoxic agents, and plasma exchange. Limited but encouraging data about the utility of antiviral treatment in the setting of HCV-associated glomerulonephritis exist, with one pooled analysis noting a sustained viral response of 42%, albeit with significant heterogeneity. Immunosuppressive therapy may be most useful for cryoglobulinemic kidney disease, with individualized approaches considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis based on the level of proteinuria and kidney failure. Of note, rituximab, a chimeric monoclonal antibody that blocks CD20 receptors on B cells, has been reported to be effective for the treatment of mixed cryoglobulinemia symptoms, including glomerulonephritis.

How to manage HIV-infected patients with chronic kidney disease in the HAART era

As human immunodeficiency virus (HIV)-infected patients now live longer while receiving highly active antiretroviral therapy (HAART), chronic kidney disease (CKD) has emerged as a significant cause of morbidity and mortality among urban HIV population. Risk factors associated with CKD in such HIV-infected population include aging, hypertension, diabetes mellitus, co-infection with hepatitis C virus, low CD4 cell count, and high HIV viral load. Clinical experience has shown that HIV-infected individuals often have one or more concurrent risk factors for CKD. The cumulative effect of multiple risk factors on the development of CKD should be noted in this population. Glomerular disease directly related to HIV infection, so-called HIV-associated nephropathy, remains an important cause of CKD among limited HIV population of African descent. The impact of exposure to nephrotoxic antiretroviral agents on the development of kidney disease is both an old and a new concern. In particular, the association of tenofovir with kidney disease has been an area of great interest. The findings regarding tenofovir's adverse effect on long-term kidney function vary among studies. Early identification and treatment of kidney disease is imperative for reducing the burden of patients requiring dialysis in HIV-infected populations. Periodic monitoring of urinary albumin excretion, tubular parameters such as low-molecular-weight proteinuria, and the estimated glomerular filtration rate may be useful for early diagnosis of patients at risk for incident CKD. This review focuses on recent developments in epidemiology, risk factors, identification, estimation, and management of CKD in HIV-infected population in the HAART era.

Hepatitis C virus, cryoglobulinemia, and kidney: novel evidence

Hepatitis C virus infection can lead to chronic active hepatitis, cirrhosis, and liver failure; however, it is also associated with a wide range of extra-hepatic complications. HCV is associated with a large spectrum of histopathological lesions in both native and transplanted kidneys, and it is increasingly recognized as an instigator of B cell lympho-proliferative disorders including mixed cryoglobulinemia. Mixed cyoglobulinemia is a systemic vasculitis primarily mediated by immune complexes; it is characterized by variable organ involvement including skin lesions, chronic hepatitis, glomerulonephritis, peripheral neuropathy, and arthralgias. The most frequent HCV-associated nephropathy is type I membranoproliferative glomerulonephritis, usually in the context of type II mixed cryoglobulinemia. Various approaches have been tried for the treatment of HCV-related glomerulonephritis, including immunosuppressive therapy (corticosteroids and cytotoxic agents), plasma exchange and antiviral agents. Data on the antiviral treatment of HCV-associated glomerulonephritis are not abundant but encouraging results have been provided. Immunosuppressive therapy is particularly recommended for cryoglobulinemic kidney disease. Recent evidence has been accumulated on rituximab therapy for HCV-related cryoglobulinemic glomerulonephritis exists but several questions related to its use remain unclear. Distinct approaches should be considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis according to the level of proteinuria and kidney failure.

Association of hepatitis C virus infection with risk of ESRD: a population-based study

BACKGROUND

The association between chronic hepatitis C virus (HCV) infection and end-stage renal disease (ESRD) has been widely debated.

STUDY DESIGN

National population-based cohort study.

SETTING & PARTICIPANTS

Insurance claims data from the Taiwan National Health Insurance Research Database in 2000-2005.

PREDICTOR

Chronic HCV infection as defined by the International Classification of Diseases, Ninth Revision, Clinical Modification.

OUTCOMES

ESRD as defined by the International Classification of Diseases, Ninth Revision, Clinical Modification.

RESULTS

We identified 6,291 adults with chronic HCV infection. The control group included 31,455 sex- and age-matched individuals without evidence of chronic hepatitis. The incidence of ESRD was 2.14-fold higher in patients with chronic HCV infection (HR, 1.53; 95% CI, 1.17-2.01; P = 0.002) than in patients without HCV infection. Age stratification analysis showed that patients aged 50-59 years with chronic HCV infection (HR, 7.77; 95% CI, 4.23-14.3; P < 0.001) had the highest risk of developing ESRD relative to patients aged 20-49 years without chronic HCV infection (interaction P < 0.001).

LIMITATIONS

Lack of clinical data.

CONCLUSIONS

Patients with chronic HCV infection are at greater risk of developing ESRD than individuals without chronic HCV infection. In addition, the risk of developing ESRD is highest in younger patients with HCV infection. Early renal screening programs should be initiated for this high-risk group of young individuals with chronic HCV infection.

Hepatitis C virus infection and kidney disease: a meta-analysis

BACKGROUND AND OBJECTIVES

Hepatitis C virus (HCV) infection and kidney disease are both highly prevalent diseases. The association between HCV and GN has been supported by previous research but little is known about the relationship between HCV and kidney disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A systematic review of the published medical literature was conducted to determine if HCV is associated with increased likelihood of kidney disease in the general population. A random-effects model was used to generate a summary estimate of the relative risk for kidney disease, defined as an estimated GFR <60 ml/min per 1.73 m(2) or proteinuria, with HCV across the published studies.

RESULTS

Nine clinical studies (817,917 unique individuals) were identified. Pooling of study results demonstrated the absence of a relationship between HCV seropositive status and reduced estimated GFR (adjusted relative risk, 1.12; 95% confidence interval, 0.91, 1.38; P=0.28) according to the random-effects model. HCV seropositive serology was an independent and significant risk factor for proteinuria (defined by urine dipstick test or spot urine albumin/creatinine ratio) in the general population, with a summary estimate for adjusted relative risk of 1.47 (95% confidence interval, 1.12, 1.94; P=0.006). Significant heterogeneity was observed between studies (Ri=0.82; P value by Q test, <0.001).

CONCLUSIONS

This meta-analysis shows that HCV is independently associated with proteinuria but not with reduced GFR in the general population. Substantial heterogeneity occurred.

Higher prevalence of chronic kidney disease and shorter renal survival in patients with chronic hepatitis C virus infection

BACKGROUND

The role of hepatitis C virus infection (HCV) in the etiology and progression of chronic kidney disease (CKD) is controversial.

AIM

To measure the prevalence of CKD and evaluate its course in patients with chronic HCV infection.

METHODS

A retrospective analysis was done after excluding patients with nephrolithiasis, structural kidney disease, and those with missing clinical information on 552 anti-HCV-positive patients and 313 patients without known HCV infection matched for age, race, and gender. CKD was defined as estimated glomerular filtration rate value of <60 mL/min/1.73 m(2) and/or persistence of proteinuria (>3 months) on urine analysis by dipstick. Viral load obtained during the initial evaluation was defined as "baseline viral load".

RESULTS

The prevalence of CKD in the anti-HCV-positive group was significantly higher compared to control group [53 (9.6%) vs. 16 (5.1%), P = 0.02]. On multivariate regression analysis, higher age, hypertension, HCV PCR > 7 × 10(5) cps/mL, and diabetes mellitus were significant independent positive predictors, whereas history of interferon treatment was significant independent negative predictor for CKD. Male gender, human immunodeficiency virus status, body weight, intravenous drug use, and HCV genotype were not predictors of CKD. Analysis of renal survival through Kaplan-Meyer curves revealed significantly shorter time to develop CKD (74 vs. 84 months, P < 0.001; log rank) and end-stage renal disease (79.9 vs. 86.5 months, P = 0.005; log rank) in the HCV group compared to the control group.

CONCLUSION

Chronic HCV infection was associated with a significantly higher prevalence of CKD compared with controls, as well as significantly shorter renal survival. A higher baseline viral load is an independent predictor of CKD.

Racial/ethnic differences in microalbuminuria among adults with prehypertension and hypertension: National Health and Nutrition Examination Survey (NHANES), 1999-2006

BACKGROUND

Microalbuminuria, a biomarker of endothelial dysfunction, is associated with increased cardiovascular, renal, and cerebrovascular morbidity and mortality, especially among ethnic minorities.

METHODS

A total of 16,567 adults in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2006 were categorized according to JNC 7 blood pressure (BP) definitions. Microalbuminuria was defined as spot urinary albumin/creatinine ratio (ACR) of 30-299 mg/g. Logistic regression estimated the odds of having microalbuminuria among BP categories compared with normal BP after adjusting for age, race/ethnicity, sex, education level, smoking status, body mass index (BMI), systolic BP, and diabetes.

RESULTS

Prevalence of microalbuminuria was 4.5% for normal BP, 6.3% for prehypertension, 12.4% for stage 1 hypertension, 25.3% for stage 2 hypertension, and 11.3% among those with treated, controlled hypertension. Compared with participants with normal BP, the adjusted odds ratios and 95% confidence intervals (CIs) for microalbuminuria were 1.3 (1.0-1.7, P = 0.03) for those with prehypertension, 2.3 (1.8-3.0, P < 0.01) with stage 1 hypertension, 4.8 (3.7-6.3 P < 0.01) with stage 2 hypertension, and 1.6 (1.3-2.1, P < 0.01) with treated, controlled hypertension. The treated controlled hypertension group exhibited the strongest race-ethnicity gradient.

CONCLUSIONS

Participants with hypertension and prehypertension had a higher likelihood of microalbuminuria than those with normal BP, especially ethnic minorities, suggesting greater target organ damage. Our observations suggest that further research is necessary to determine whether microalbuminuria can be used as a screening tool in adults with prehypertension, to identify adults at highest risk for cardiovascular disease or decline in renal function.