The influence of hepatitis C virus coinfection on the risk of lipid abnormalities in a cohort of HIV-1-infected patients after initiation of highly active antiretroviral therapy

Metabolic and Cardiovascular Complications in HIV/HCV-Co-infected Patients

PURPOSE OF REVIEW

Fifteen to thirty percent of HIV-infected persons in North America and Europe are co-infected with chronic hepatitis C (HCV). The latter is associated with a significant number of extra-hepatic metabolic complications that could compound HIV-associated increased cardiovascular risk. This article reviews the basic science and epidemiologic and clinical evidence for increased cardio-metabolic risk among HIV/HCV-co-infected patients and discusses potential underlying mechanisms. We will finally review the impact of control of HCV viremia on the cardio-metabolic morbidity and mortality of HIV/HCV-co-infected patients.

RECENT FINDINGS

HCV infection is associated with a number of immune-related complications such as cryoglobulinemia but also metabolic complications including dyslipidemias, hepatic steatosis, insulin resistance, diabetes, and chronic kidney disease. The incidence of these complications is higher among HIV-co-infected patients and might contribute to increased mortality. The potential mechanisms of increased cardiovascular risk among HIV/HCV-co-infected subjects include endothelial dysfunction, chronic inflammation and immune activation, the cardio-metabolic effects of HCV-induced hepatic steatosis and fibrosis or insulin resistance, and chronic kidney disease. However, epidemiologic studies show discordant findings as to whether HCV co-infection further increases the risk of atherosclerotic cardiovascular diseases (acute myocardial infarctions and strokes) among HIV-infected patients. Nonetheless, successful treatment of HCV is associated with significant improvements in cardio-metabolic risk factors including diabetes mellitus. HCV co-infection is associated with a higher incidence of metabolic complications-and likely increased risk of cardiovascular events-that might contribute to increased mortality in HIV. These appear to improve with successful HCV therapy.

HIV and HAART-Associated Dyslipidemia

Effective highly active antiretroviral therapy (HAART) for human immunodeficiency virus-1 (HIV) infection has led to marked improvement in life-expectancy for those infected with HIV. Despite reductions in the incidence of AIDS with effective treatment, patients continue to experience considerable morbidity and mortality from non-AIDS illness such as premature cardiovascular disease, liver failure and renal failure. These morbidities, particularly premature cardiovascular disease, are thought to be related to a combination of the effects of an ageing HIV-infected population coupled with long-term effects of HIV infection and antiretroviral therapy (ART). One of the principle drivers behind the well documented increase in the risk of cardiovascular disease in HIV-infected patients is dyslipidemia.

This review will focus on the clinical presentation of HIV and ART-associated dyslipidemia, what is known of its patho-physiology, including associations with use of specific antiretroviral medications, and suggest screening and management strategies.

Impact of NRTIs on lipid levels among a large HIV-infected cohort initiating antiretroviral therapy in clinical care

OBJECTIVE

to assess the associations between nucleoside reverse transcriptase inhibitors (NRTIs) and change in lipid levels among a large cohort of HIV-infected patients in routine clinical care initiating their first potent antiretroviral regimen.

DESIGN

longitudinal observational cohort study from the Centers for AIDS Research Network of Integrated Clinical Systems (CNICS) cohort.

METHODS

we used generalized estimating equations to examine the association between NRTIs and lipids accounting for within-patient correlations between repeated measures and key clinical and demographic characteristics including other antiretroviral medications.

RESULTS

among 2267 individuals who started their first antiretroviral regimen, tenofovir with emtricitabine or lamivudine was associated with lower levels for total cholesterol, low-density lipoprotein (LDL), triglycerides, non-high-density lipoprotein (HDL), and HDL, compared with other NRTI pairs in adjusted analyses. LDL levels were highest among patients receiving didanosine/lamivudine. Triglyceride levels were highest in stavudine/lamivudine users. HDL levels were highest among patients receiving didanosine/stavudine. Hepatitis C infection and younger age were also associated with lower lipid levels.

CONCLUSION

we found clinically important heterogeneity within the NRTI class of antiretroviral medications regarding their effect on lipid levels over time. Although the lipid profile of tenofovir with emtricitabine or lamivudine appeared to be less pro-atherogenic in this large longitudinal study of HIV-infected patients in routine clinical care, there was no association with beneficial HDL levels. In general, the change in lipid levels associated with most antiretroviral agents, particularly those NRTI combinations currently in common use, are relatively modest. Additional studies are needed to understand the long-term implications of these findings on cardiovascular disease risk.

Hepatitis C virus coinfection and the risk of cardiovascular disease among HIV-infected patients

BACKGROUND

Among HIV-infected patients, hepatitis C virus (HCV) coinfection is associated with lower cholesterol levels, but it remains unclear how it affects cardiovascular outcomes.

METHODS

We performed logistic regression to evaluate acute myocardial infarction (AMI) and cerebrovascular disease (CVD) events by HCV status among HIV-infected US veterans in the highly active antiretroviral therapy (HAART) era (1996-2004). We then performed survival analyses to evaluate incident AMI and CVD, exploring antiretroviral therapy (ART) as a time-dependent variable.

RESULTS

A total of 19 424 HIV-infected patients [31.6% of whom were HCV-coinfected (HIV/HCV)] contributed 76 376 patient-years of follow-up. HCV coinfection was associated with lower rates of hypercholesterolaemia (18.0% in HIV/HCV vs. 30.7% in HIV-only patients; P<0.001), but higher rates of hypertension (43.8%vs. 35.6%; P<0.0001), type 2 diabetes mellitus (16.2%vs. 11.1%; P<0.0001) and smoking (36.7%vs. 24.7%; P=0.009). Rates of AMI and CVD were significantly higher among HIV/HCV than HIV-only patients: 4.19 vs. 3.36 events/1000 patient-years, respectively (P<0.001), for AMI; and 12.47 vs. 11.12 events/1000 patient-years, respectively (P<0.001), for CVD. When analyses were controlled for diabetes mellitus, hypertension, age and duration of ART, hazard ratios (HRs) among those with HIV/HCV (vs. HIV only) were 1.25 [95% confidence interval (CI) 0.98-1.61; P=0.072] for AMI and 1.20 (CI 1.04-1.38; P=0.013) for CVD. Hypertension (HR 2.05; P<0.001), greater age (HR 1.79; P<0.001) and longer duration (cumulative years) of antiretroviral use (HR 1.12; P=0.0411) were also associated with increased risk of AMI in the adjusted model.

CONCLUSIONS

In the HAART era, HCV coinfection was associated with a significantly increased risk of CVD and a trend towards an increased risk of AMI among HIV-infected patients.

Cystatin C and creatinine in an HIV cohort: the nutrition for healthy living study

BACKGROUND

Human immunodeficiency virus (HIV)-infected persons have an increased risk of chronic kidney disease (CKD). Serum creatinine level may underestimate the prevalence of CKD in subjects with decreased lean body mass or liver disease. Level of serum cystatin C, an alternative kidney function marker, is independent of lean body mass.

STUDY DESIGN

Cross-sectional.

SETTING & PARTICIPANTS

250 HIV-infected subjects on highly active antiretroviral therapy in the Nutrition for Healthy Living (NFHL) cohort; 2,628 National Health and Nutrition Examination Survey (NHANES) 2001-2002 subjects.

PREDICTORS & OUTCOMES

Comparison of serum creatinine levels in NFHL to those in NHANES subjects; comparison of CKD in NFHL subjects ascertained using serum creatinine versus cystatin C levels.

MEASUREMENTS

Standardized serum creatinine, serum cystatin C, glomerular filtration rate (GFR) estimated from serum creatinine and cystatin C levels.

RESULTS

Creatinine levels were lower in NFHL than NHANES subjects despite greater rates of hepatitis, diabetes, and drug use (mean difference, -0.18 mg/dL; P < 0.001 adjusted for age, sex, and race). Of NFHL subjects, only 2.4% had a creatinine-based estimated GFR less than 60 mL/min/1.73 m(2), but 15.2% had a cystatin-based estimated GFR less than 60 mL/min/1.73 m(2).

LIMITATIONS

GFR was estimated rather than measured. Other factors in addition to GFR may affect creatinine and cystatin C levels. Measurements of proteinuria were not available.

CONCLUSIONS

Serum creatinine levels may overestimate GFRs in HIV-infected subjects. Kidney disease prevalence may be greater than previously appreciated.

Hepatitis C infection is associated with lower lipids and high-sensitivity C-reactive protein in HIV-infected men

Increased cardiovascular risk has been linked to HIV infection and combination antiretroviral therapy, but the impact of hepatitis C virus (HCV) status on indices of cardiovascular risk has not been routinely assessed in the HIV-infected population. The objective of this study was to analyze associations of HCV, HIV, and combination antiretroviral therapy with lipid levels and C-reactive protein (CRP) among older men. We measured fasting total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride, and high-sensitivity CRP serum levels in a cross-sectional study of 108 HIV-infected and 74 HIV-uninfected at-risk older men. One hundred ten men (60%) had detectable HCV RNA, with no difference by HIV status (p = 0.25). The majority (88%) of men with HCV infection had a history of injection drug use. Among all men, HCV infection was independently associated with lower total cholesterol (p < 0.001), LDL-C (p < 0.001), triglycerides (p = 0.01), and CRP (p = 0.001). Among HIV-infected men, HCV infection was associated with lower total cholesterol (p < 0.001), LDL-C (p < 0.001), and CRP (p = 0.004). HCV infection was associated with lower triglycerides among men on protease inhibitors (PI) (p = 0.02) and non-PI combination antiretroviral therapy (p = 0.02), but not among antiretroviral-naïve men. These findings demonstrate an association of lower serum lipid and CRP levels with HCV infection and suggest that HCV status should be assessed as an important correlate of cardiovascular risk factors in studies of older men with or at risk for HIV.

Lipid abnormalities in HIV/hepatitis C virus-coinfected patients

BACKGROUND

Among HIV-infected patients, hepatitis C virus (HCV) coinfection is associated with increased rates of lipodystrophy and insulin resistance. Its impact on HIV-associated dyslipidaemia is less clear.

METHODS

The lipid profiles of all HIV-infected patients and a subset of HCV-infected patients seen at the VA Medical Center in Dallas from January 2003 to March 2004 were analysed. Demographic data, HCV serostatus, and HIV treatment history were recorded. Lipid profiles of HIV/HCV-coinfected patients were compared with those of HIV-monoinfected and HCV-monoinfected patients.

RESULTS

A total of 359 HIV-infected patients, 91 (25.3%) of whom were HCV coinfected, and 112 HCV-infected patients were included in the analysis. Among the HIV-infected patients, HCV coinfection was associated with a reduced risk of hypercholesterolaemia [9.9% vs 24.8%; relative risk (RR)=0.333; 95% confidence interval (CI)=0.158-0.699; P<0.001] and hypertriglyceridaemia (48.4% vs 60.3%; RR=0.616; 95% CI=0.382-0.994; P=0.031). After controlling for duration of protease inhibitor (PI) therapy, race, alanine aminotransferase (ALT) concentration and platelet count, HCV remained an independent predictor of hypercholesterolaemia (RR=0.369; P=0.01) and any dyslipidaemia (RR=0.531; P=0.019). In addition, the rate of dyslipidaemias was lower among HCV-monoinfected than HIV/HCV-coinfected patients (29.5% vs 50.5; P=0.002). White race was also an independent predictor of dyslipidaemia (73.8% vs 50.7%; RR=2.32; 95% CI=1.44-3.76; P=0.001).

CONCLUSIONS

HCV coinfection independently predicted lower rates of dyslipidaemia among HIV-infected patients. An analysis of lipid kinetics among mono- and coinfected patients may elucidate the mechanisms of the apparent protective effect of HCV infection.

Influence of Hepatitis C Genotypes on Lipid Levels in HIV-Positive Patients during Highly Active Antiretroviral Therapy

Background

The independent role of HCV genotype a3 (HCV-3) in dyslipidaemia following highly active anti-retroviral therapy (HAART) is still unexplored.

Methods

Analysis of data from a cohort of 307 HIV/HCV-coinfected patients and 415 HIV-monoin-fected controls was conducted. Patients with available lipid levels at baseline and minimum 3-month follow-up were ranked into three groups by HCV status (HCV-3, other HCV genotypes or HCV negative). Univariate and multivariate GEE models were performed to assess factors correlated with lipid serum levels as coefficient (Coef., defined as mean difference [mg/dl] across the follow-up). Univariate and multivariate logistic regression analyses were performed for prediction of relevant hypertriglyceridaemia (≥500 mg/dl) and relevant hyper-cholesterolaemia (≥240 mg/dl) at 3 months of follow-up.

Results

HCV-3 correlated with lower triglyceridaemia (Coef.=-38.22; P=0.001), independently from the other considered variables, including age, gender and use of stavudine or lopinavir. Even though HCV infection per se appeared to be protective, HCV-3 in particular was also independently associated with lower choles-terolaemia (Coef.=-46.35; P<0.001). At logistic regression analyses, HCV-3, but not HCV-non-3, was associated with lower risk of relevant hypercholestero-laemia (odds ratio [OR] 0.06; P=0.01) and relevant hypertriglyceridaemia (OR 0.11; P=0.05), independently from other considered variables.

Conclusions

Our data confirm that HCV coinfection per se is associated with lower risk of hypercholestero-laemia after HAART. This effect was particularly attributed to HCV-3, which was the only genotype associated with lower triglyceridaemia during HAART.