Effect of hepatitis C treatment on CD4+ T-cell counts and the risk of death in HIV-HCV-coinfected patients: the COHERE collaboration

Effect of incident hepatitis C infection on CD4+ cell count and HIV RNA trajectories based on a multinational HIV seroconversion cohort

BACKGROUND

Most studies on hepatitis C virus (HCV)/HIV-coinfection do not account for the order and duration of these two infections. We aimed to assess the effect of incident HCV infection, and its timing relative to HIV seroconversion (HIVsc) in HIV-positive MSM on their subsequent CD4+ T-cell count and HIV RNA viral load trajectories.

METHODS

We included MSM with well estimated dates of HIVsc from 17 cohorts within the CASCADE Collaboration. HCV-coinfected MSM were matched to as many HIV monoinfected MSM as possible by HIV-infection duration and combination antiretroviral therapy (cART) use. We used multilevel random-effects models stratified by cART use to assess differences in CD4+ cell count and HIV RNA viral load trajectories by HCV-coinfection status.

FINDINGS

We matched 214 (ART-naive) and 147 (on cART) HCV-coinfected MSM to 5384 and 3954, respectively, matched controls. The timing of HCV seroconversion (HCVsc) relative to HIVsc had no demonstrable effect on HIV RNA viral load or CD4+ cell count trajectories. In the first 2-3 years following HCVsc CD4 cell counts were lower among HCV-coinfected MSM, but became comparable with HIV monoinfected MSM thereafter. In ART-naive MSM, during the first 2 years after HCVsc, HIV RNA viral load levels were lower or comparable with HIV monoinfected, tending to be higher thereafter. In MSM on cART, HCV had no significant effect on having a detectable HIV RNA viral load.

INTERPRETATION

Irrespective of the duration of HIV infection when HCV is acquired, CD4+ cell counts were temporarily lower following HCVsc, even when on cART. The clinical implications of our findings remain to be further elucidated.

M, Diana B, Monique T, Christine S, Rikke SB, Nina FM, Dorthe R, David H, Matthias E, Ian W, Stéphane DW. Cohort Profile: Collaboration of Observational HIV Epidemiological Research Europe (COHERE) in EuroCoord

Many questions about the long-term effects of combination antiretroviral therapy (cART) on clinical outcomes in people living with HIV (PLWH) and their impact on health systems remain unanswered. The Collaboration of Observational HIV Epidemiological Research Europe (COHERE) was formed in 2005 to pool and harmonize existing longitudinal data on people living with HIV in Europe, to answer key research questions that could not be addressed adequately by individual cohorts. Key research questions include long-term prognosis, rare outcomes, and variations across patient groups, settings and health systems. COHERE uses the HIV Cohorts Data Exchange Protocol, a standardized and validated method of data structure and transfer, to compile data from over 40 cohorts of PLWH residing in Europe, representing 331 481 individuals, including 2808 children (<13), representing 2 135 896 person-years of follow-up. COHERE compiles data on clinical characteristics, antiretroviral therapy and other medications, HIV seroconversion, opportunistic infections, laboratory results and socio demographic data. External collaborators interested in conducting a project in COHERE should submit a project proposal to the Regional Coordinating Centres in Bordeaux and Copenhagen for review by COHERE’s governing bodies (see www.cohere.org for further information).

Systematic review and meta-analysis of hepatitis C virus infection and HIV viral load: new insights into epidemiologic synergy

INTRODUCTION

Hepatitis C virus (HCV) and HIV infection frequently co-occur due to shared transmission routes. Co-infection is associated with higher HCV viral load (VL), but less is known about the effect of HCV infection on HIV VL and risk of onward transmission.

METHODS

We undertook a systematic review comparing 1) HIV VL among ART-naïve, HCV co-infected individuals versus HIV mono-infected individuals and 2) HIV VL among treated versus untreated HCV co-infected individuals. We performed a random-effects meta-analysis and quantified heterogeneity using the I(2) statistic. We followed Cochrane Collaboration guidelines in conducting our review and PRISMA guidelines in reporting results.

RESULTS AND DISCUSSION

We screened 3925 articles and identified 17 relevant publications. A meta-analysis found no evidence of increased HIV VL associated with HCV co-infection or between HIV VL and HCV treatment with pegylated interferon-alpha-2a/b and ribavirin.

CONCLUSIONS

This finding is in contrast to the substantial increases in HIV VL observed with several other systemic infections. It presents opportunities to elucidate the biological pathways that underpin epidemiological synergy in HIV co-infections and may enable prediction of which co-infections are most important to epidemic control.

Changes in HIV RNA and CD4 cell count after acute HCV infection in chronically HIV-infected individuals

OBJECTIVE

Little is known about the impact of acute hepatitis C virus (HCV) co-infection on HIV-1 disease progression. We investigated CD4 cell count and HIV RNA concentration changes after HCV infection in individuals chronically infected with HIV-1.

METHODS

We selected individuals that had the last negative and first positive HCV RNA test less than 1 year apart. Bivariate linear mixed-effects regression was used to model trends in HIV RNA level and CD4 cell count from 2 years before the last negative HCV RNA test until the first of the following dates: start of anti-HCV medication, change in combination antiretroviral therapy (cART) status, and end of follow-up.

RESULTS

At the estimated time of HCV co-infection, of 89 individuals, 63 (71%) were cART-treated and 26 (29%) were not on cART. In persons on cART, median CD4 cell count declined from 587 to 508 cells per cubic millimeter (P < 0.0001) during the first 5 months after HCV infection and returned to 587 cells per cubic millimeter after 2.2 years. Also, the probability of an HIV RNA >50 copies per milliliter peaked to 18.6% at HCV co-infection, with lower probabilities 6 months before (3.5%, P = 0.006 compared with peak probability) and after (2.9%, P = 0.009). In persons not on cART, no significant impact of HCV co-infection on trends in the HIV RNA level or CD4 cell count was observed.

CONCLUSIONS

Acute HCV infection in cART-treated, chronically HIV-infected patients was associated with a temporary decrease in CD4 cell counts and increased risk of HIV viremia >50 copies per milliliter. This may increase the risk of further HIV transmission.

Application of marginal structural models in pharmacoepidemiologic studies: a systematic review

PURPOSE

We systematically reviewed pharmacoepidemiologic studies published in 2012 that used inverse probability weighted (IPW) estimation of marginal structural models (MSM) to estimate the effect from a time-varying treatment.

METHODS

Potential studies were retrieved through a citation search within Web of Science and a keyword search within PubMed. Eligibility of retrieved studies was independently assessed by at least two reviewers. One reviewer performed data extraction, and a senior epidemiologist confirmed the extracted information for all eligible studies.

RESULTS

Twenty pharmacoepidemiologic studies were eligible for data extraction. The majority of reviewed studies did not report whether the positivity assumption was checked. Six studies performed intention-to-treat analyses, but none of them reported adherence levels after treatment initiation. Eight studies chose an as-treated analytic strategy, but only one of them reported modeling the multiphase of treatment use. Almost all studies performing as-treated analyses chose the most recent treatment status as the functional form of exposure in the outcome model. Nearly half of the studies reported that the IPW estimate was substantially different from the estimate derived from a standard regression model.

CONCLUSIONS

The use of IPW method to control for time-varying confounding is increasing in medical literature. However, reporting of the application of the technique is variable and suboptimal. It may be prudent to develop best practices in reporting complex methods in epidemiologic research.

Outcomes and management of viral hepatitis and human immunodeficiency virus co-infection in liver transplantation

Liver transplantation for human immunodeficiency virus (HIV) positive patients with viral hepatitis co-infection is increasingly offered in many North American and European liver transplant centers. Prior studies have demonstrated acceptable post-transplant outcomes and no increased risk of HIV complications in patients co-infected with hepatitis B virus (HBV). However, liver transplantation in HIV positive patients with hepatitis C virus (HCV) has poorer outcomes overall, requiring careful selection of candidates. This review aims to summarize the published literature on outcomes after transplant in HIV patients with HBV or HCV related end-stage liver disease and recommendations for management. In particular the pre-transplant factors impacting outcomes in HCV/HIV co-infected candidates and importance of multidisciplinary management will be discussed.

Temporal changes and regional differences in treatment uptake of hepatitis C therapy in EuroSIDA

OBJECTIVES

All HIV/hepatitis C virus (HCV)-coinfected patients with chronic HCV infection and ≥ F2 fibrosis should be considered for HCV therapy. This study aimed to determine the rate of HCV treatment uptake among coinfected patients in Europe.

METHODS

EuroSIDA patients with viraemic HCV infection were included in the study. Poisson regression was used to identify temporal changes and regional differences in HCV treatment uptake.

RESULTS

A total of 1984 patients were included in the study, with a median follow-up time of 168 months [interquartile range (IQR) 121-204 months]. To date, 501 (25.3%) HIV/HCV-coinfected patients have received HCV therapy. Treatment incidence rose from 0.33 [95% confidence interval (CI) 0.16-0.50] per 100 person-years of follow-up (PYFU) in 1998 to 5.93 (95% CI 4.49-7.38) in 2007, falling to 3.78 (95% CI 2.50-5.07) in 2009. After adjustment, CD4 cell count > 350 cells/μL [incidence rate ratio (IRR) 1.33 (95% CI 1.06-1.67) vs. CD4 count 200-350 cells/μL] and ≥F2 liver fibrosis [IRR 1.60 (95% CI 1.14-2.25; P = 0.0065) vs. < F2 fibrosis] were predictors of anti-HCV treatment initiation. However, 22% of patients who remain untreated for HCV, with fibrosis data available, had ≥F2 fibrosis and should have been considered for treatment, while only 36% of treated patients had ≥F2 fibrosis.

CONCLUSIONS

Although treatment incidence for HCV has increased, there remain a large proportion of patients indicated for treatment who have yet to be treated.