Hepatitis C virus cure does not impact kidney function decline in HIV co-infected patients

Host factors predisposing to kidney disease in people with HIV

PURPOSE OF REVIEW

To highlight advances in understanding of host factors, in particular host genetics, in the development of chronic kidney disease (CKD) in people with HIV.

RECENT FINDINGS

In Black populations, the G1 and G2 variants of the apolipoprotein L1 (APOL1) gene predispose to HIV-associated nephropathy (HIVAN). The risk of HIVAN is mostly confined to individuals with two APOL1 variants (kidney-risk genotypes). APOL1 kidney-risk genotypes are present in approximately 80% of patients with HIVAN and account for nearly half the burden of end-stage CKD in people of African ancestry with HIV. Progress has been made in elucidating the mechanisms of kidney injury in APOL1 nephropathy, and several targeted molecular therapies are being investigated in clinical trials. Genome- and epigenome-wide association studies are identifying additional genes and pathways that may be involved in the pathogenesis of CKD in people with HIV.

SUMMARY

Genetic variants of APOL1 are strongly associated with severe CKD and contribute to the high rates of CKD in Black populations with HIV. Most individuals with APOL1 kidney-risk genotypes, however, do not develop kidney disease and further studies are required to understand the role of additional genetic and environmental factors that may affect CKD risk in this population.

Three-step matching algorithm to enhance between-group comparability and minimize confounding in comparative effectiveness studies

We developed a three-step matching algorithm to enhance the between-group comparability for comparative drug effect studies involving prevalent new-users of the newer study drug versus older comparator drug(s). The three-step matching scheme is to match on: (1) index date of initiating the newer study drug to align the cohort entry time between study groups, (2) medication possession ratio measures that consider prior exposure to all older comparator drugs, and (3) propensity scores estimated from potential confounders. Our approach is illustrated with a comparative cardiovascular safety study of glucagon-like peptide-1 receptor agonist (GLP-1ra) versus sulfonylurea (SU) in type 2 diabetes patients using Taiwan’s National Health Insurance Research Database 2003–2015. 66% of 3195 GLP-1ra users had previously exposed to SU. The between-group comparability was well-achieved after implementing the matching algorithm (i.e., standardized mean difference < 0.2 for all baseline patient characteristics). Compared to SU, the use of GLP-1ra yielded a significantly reduced risk of the primary composite cardiovascular events (hazard ratio [95% confidence interval]: 0.71 [0.54–0.95], p = 0.022). Our matching scheme can enhance the between-group comparability in prevalent new-user cohort designs to minimize time-related bias, improve confounder adjustment, and ensure the reliability and validity of study findings.

Impact of antiviral therapy with direct acting antiviral agents (DAAs) on kidney disease in patients with chronic hepatitis C

Hepatitis C virus and chronic kidney disease are major public health issues all over the world and controversy persists regarding the role of Hepatitis C as a risk factor for the development of chronic kidney disease in the adult general population. Numerous studies found a relationship between positive anti-HCV antibody serologic prevalence and increased frequency of incidence, prevalence and accelerated progression of chronic kidney disease (CKD) over time. However, this has not been universally accepted. One method to analyze the relationship between anti-HCV status and CKD is to evaluate the impact of anti-HCV antiviral therapy on the risk of CKD in the general population. The availability of safe and effective drugs (direct-acting antiviral agents) for HCV eradication supports this approach. Novel data support the notion that sustained viral response with anti-HCV regimens leads to improvement of hepatic and extrahepatic outcomes. A systematic review with meta-analysis of clinical observational studies was recently performed on this point. Fifteen studies were retrieved (N.=356, 285 patients); a relationship between sustained viral response and lower rate of kidney disease was noted- the summary estimate for adjusted risk of kidney disease was 2.5 (95% CI: 1.41; 4.41) (P=0.0016). An association between anti-HCV therapy and reduced risk of kidney disease after comparison of treated vs. untreated cohorts was observed, the summary estimate for adjusted HR was 0.44 (95% CI: 0.25; 0.63) (P=0.0001). Several biologic mechanisms have been cited to explain the detrimental role of HCV on kidney disease in the general population, and a direct and indirect activity of HCV on atherogenesis at kidney level has been mentioned. Clinical and experimental studies are under way.

Influence of hepatitis C virus co-infection and hepatitis C virus treatment on risk of chronic kidney disease in HIV-positive persons

BACKGROUND

Hepatitis C virus (HCV) infection has been associated with increased risk of chronic kidney disease (CKD). We investigated the impact of HCV cure on CKD in HIV-positive persons in the EuroSIDA study.

METHODS

HIV-positive persons with known HCV status and at least three serum creatinine measurements after 1/1/2004 were compared based on time-updated HCV-RNA and HCV treatment: anti-HCV-negative, spontaneously cleared HCV, chronic untreated HCV, successfully treated HCV, and HCV-RNA positive after HCV treatment. Poisson regression compared incidence rates of CKD [confirmed (>3 months apart) eGFR <60 ml/min per 1.73 m] between HCV strata.

RESULTS

Fourteen thousand, seven hundred and fifty-four persons were included; at baseline 9273 (62.9%) were HCV-Ab negative, 696 (4.7%) spontaneous clearers, 3021 (20.5%) chronically infected, 922 (6.2%) successfully treated and 842 (5.7%) HCV-RNA positive after treatment. During 115 335 person-years of follow-up (PYFU), 1128 (7.6%) developed CKD; crude incidence 9.8/1000 PYFU (95% CI 9.2-10.4). After adjustment, persons anti-HCV negative [adjusted incidence rate ratio (aIRR) 0.59; 95% CI 0.46-0.75] and spontaneous clearers (aIRR 0.67; 95% CI 0.47-0.97) had significantly lower rates of CKD compared with those cured whereas persons chronically infected (aIRR 0.85; 95% CI 0.65-1.12) and HCV-RNA positive after treatment (aIRR 0.71; 95% CI 0.49-1.04) had similar rates. Analysis in those without F3/F4 liver fibrosis using a more rigorous definition of CKD showed similar results.

CONCLUSION

This large study found no evidence that successful HCV treatment reduced CKD incidence. Confounding by indication, where those with highest risk of CKD were prioritized for HCV treatment in the DAA era, may contribute to these findings.

Dolutegravir plus rilpivirine as dual regimen in virologically suppressed HIV-1 infected patients in a clinical setting

Objectives: There are scarce data on the combination of dolutegravir (DTG) plus rilpivirine (RPV) in the real world, including patients with hepatitis C virus (HCV) coinfection, toxicity or previous failure, or at risk for severe drug-drug interactions (DDIs). Methods: Prospective cohort study of virologically suppressed HIV-1 infected patients, without resistance to DTG or RPV, switched to this dual regimen because of toxicity or risk of DDIs (NCT02491242). Results: Overall, 102 patients (mean age 54 years, 28% women) were included. Fifty-seven were coinfected with HCV (fibrosis grade 4 in 27 cases, 1 liver transplantation). Seven patients had chronic kidney disease (1 renal transplantation). At week 48, only 1 virologic failure occurred (<1%), and 6 patients (6%) left the regimen (3 with central nervous system adverse events, 1 each due to pregnancy, metformin interaction, and lost to follow up). Thus, the overall treatment success rates were 93% (95% CI, 88%-98%; ITT-e, snapshot analysis) and 96% (95% CI, 92%-99%; per protocol analysis). The CD4/CD8 ratio increased slightly (median, +0.03). Triglycerides levels improved significantly (-18.8%, p < 0.01). The creatinine-based estimated glomerular filtration rate decreased by a mean of -8.4 ml/min/1.73 m², but tubular renal parameters improved. A paired dual X-ray absorptiometry scan showed a mild improvement in spine (mean, +1.15%; -0.57 to +3.3%) and in femoral neck bone mineral density (mean, +0.4%; -3.3% to +2.57%). Conclusions: In the clinical setting, switching to the combination of DTG plus rilpivirine in virologically suppressed HIV-1 patients is effective and safe, and improves lipid, renal and bone evolution.

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.