Predictors of renal outcome in HIV-associated nephropathy

An Update on Viral Infection-Associated Collapsing Glomerulopathy

The COVID-19 era has been a reminder to clinicians around the world of the important role that viral infections play in promoting glomerular disease. Several viral infections including human immunodeficiency virus (HIV), severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, cytomegalovirus, and parvovirus B19 can cause podocyte injury and present with a collapsing glomerulopathy (CG) variant of focal segmental glomerulosclerosis or minimal change disease. CG associated with COVID-19 has been termed COVID-19-associated nephropathy due to its striking resemblance to HIV-associated nephropathy. Host susceptibility is a major determinant of viral infection-associated CG, and the presence of two APOL1 risk variants explains most of the racial predilection to viral-associated CG observed in individuals of African ancestry. Interactions between APOL1 risk variants, viral genes, and the systemic inflammatory response to viral infection all contribute to kidney injury. This review will summarize our current knowledge of viral infection-associated CG, focusing primarily on the clinical presentation, histological features, mechanisms, and disease course of HIV-associated nephropathy and COVID-19-associated nephropathy.

Emerging Viral Infections and the Potential Impact on Hypertension, Cardiovascular Disease, and Kidney Disease

Viruses are ubiquitous in the environment and continue to have a profound impact on human health and disease. The COVID-19 pandemic has highlighted this with impressive morbidity and mortality affecting the world's population. Importantly, the link between viruses and hypertension, cardiovascular disease, and kidney disease has resulted in a renewed focus and attention on this potential relationship. The virus responsible for COVID-19, SARS-CoV-2, has a direct link to one of the major enzymatic regulatory systems connected to blood pressure control and hypertension pathogenesis, the renin-angiotensin system. This is because the entry point for SARS-CoV-2 is the ACE2 (angiotensin-converting enzyme 2) protein. ACE2 is one of the main enzymes responsible for dampening the primary effector peptide Ang II (angiotensin II), metabolizing it to Ang-(1-7). A myriad of clinical questions has since emerged and are covered in this review. Several other viruses have been linked to hypertension, cardiovascular disease, and kidney health. Importantly, patients with high-risk apolipoprotein L1 (APOL1) alleles are at risk for developing the kidney lesion of collapsing glomerulopathy after viral infection. This review will highlight several emerging viruses and their potential unique tropisms for the kidney and cardiovascular system. We focus on SARS-CoV-2 as this body of literature in regards to cardiovascular disease has advanced significantly since the COVID-19 pandemic.

Genetic Variants of APOL1 Are Major Determinants of Kidney Failure in People of African Ancestry With HIV

Introduction

Variants of the APOL1 gene are associated with chronic kidney disease (CKD) in people of African ancestry, although evidence for their impact in people with HIV are sparse.

Methods

We conducted a cross-sectional study investigating the association between APOL1 renal risk alleles and kidney disease in people of African ancestry with HIV in the UK. The primary outcome was end-stage kidney disease (ESKD; estimated glomerular filtration rate [eGFR] of <15 ml/min per 1.73 m2, chronic dialysis, or having received a kidney transplant). The secondary outcomes included renal impairment (eGFR <60 ml/min per 1.73 m2), albuminuria (albumin-to-creatinine ratio [ACR] >30 mg/mmol), and biopsy-proven HIV-associated nephropathy (HIVAN). Multivariable logistic regression was used to estimate the associations between APOL1 high-risk genotypes (G1/G1, G1/G2, G2/G2) and kidney disease outcomes.

Results

A total of 2864 participants (mean age 48.1 [SD 10.3], 57.3% female) were genotyped, of whom, 354 (12.4%) had APOL1 high-risk genotypes, and 99 (3.5%) had ESKD. After adjusting for demographic, HIV, and renal risk factors, individuals with APOL1 high-risk genotypes were at increased odds of ESKD (odds ratio [OR] 10.58, 95% CI 6.22-17.99), renal impairment (OR 5.50, 95% CI 3.81-7.95), albuminuria (OR 3.34, 95% CI 2.00-5.56), and HIVAN (OR 30.16, 95% CI 12.48-72.88). An estimated 49% of ESKD was attributable to APOL1 high-risk genotypes.

Conclusion

APOL1 high-risk genotypes were strongly associated with kidney disease in people of African ancestry with HIV and accounted for approximately half of ESKD cases in this cohort.

Sickle Cell Trait and Kidney Disease in People of African Ancestry With HIV

Introduction

Sickle cell trait (SCT) has been associated with chronic kidney disease (CKD) in African Americans, although evidence for its impact in Africans and people with HIV is currently lacking. We conducted a cross-sectional study investigating the association between SCT and kidney disease in people of African ancestry with HIV in the UK.

Methods

The primary outcome was estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m2. Secondary outcomes were eGFR <90 ml/min per 1.73 m2, end-stage kidney disease (ESKD; eGFR <15 ml/min per 1.73 m2, chronic dialysis, or having received a kidney transplant), proteinuria (protein-to-creatinine ratio >50 mg/mmol), and albuminuria (albumin-to-creatinine ratio >3 mg/mmol). Multivariable logistic regression was used to estimate the associations between SCT and kidney disease outcomes.

Results

A total of 2895 participants (mean age 48.1 [SD 10.3], 57.2% female) were included, of whom 335 (11.6%) had SCT and 352 (12.2%) had eGFR <60 ml/min per 1.73 m2. After adjusting for demographic, HIV, and kidney risk factors including APOL1 high-risk genotype status, individuals with SCT were more likely to have eGFR <60 ml/min per 1.73 m2 (odds ratio 1.62 [95% CI 1.14-2.32]), eGFR <90 ml/min per 1.73 m2 (1.50 [1.14-1.97]), and albuminuria (1.50 [1.09-2.05]). Stratified by APOL1 status, significant associations between SCT and GFR <60 ml/min per 1.73 m2, eGFR <90 ml/min per 1.73 m2, proteinuria, and albuminuria were observed for those with APOL1 low-risk genotypes.

Conclusion

Our results extend previously reported associations between SCT and kidney disease to people with HIV. In people of African ancestry with HIV, these associations were largely restricted to those with APOL1 low-risk genotypes.

Impact of Antiretroviral Therapy on Kidney Disease in HIV Infected Individuals - A Qualitative Systematic Review

Kidney disease is the fourth most common cause of non-AIDS-related mortality in people living with HIV. Combination antiretroviral therapy (cART) remains the cornerstone of treatment. However, little is known about the impact of cART on disease outcomes in patients with HIV-associated nephropathy (HIVAN) and HIV-immune complex kidney disease (HIVICK). This systematic review evaluates the impact of cART on progression to end-stage kidney disease (ESKD) and other outcomes in HIV-infected individuals. We conducted a literature search utilizing PubMed, and Cochrane database and 11 articles met inclusion criteria for analysis of which nine HIVAN studies showed decreased progression to ESKD or death for subjects when treated with cART versus those untreated. However, two studies showed no survival advantage with cART. Three HIVICK studies showed improvement in delaying ESKD in subjects on cART compared to untreated subjects. cART appeared to reduce the risk to ESKD or death in patients with both HIVAN and HIVICK.

Profiling Biomarkers in HIV Glomerular Disease – Potential for the Non-Invasive Diagnosis of HIVAN?

Background

There is a wide spectrum of kidney pathology in human immunodeficiency virus (HIV) infection, affecting all structures of the kidney. The histology of HIV chronic kidney disease (CKD) is diverse, ranging from HIV-associated nephropathy (HIVAN) to focal glomerulosclerosis (FSGS), HIV-immune complex disease (HIV-ICD), other glomerulopathies and tubulo-interstitial nephritis. Definitive diagnosis is by kidney biopsy, an invasive procedure. However, serum and urinary biomarkers may be useful in predicting the histological diagnosis of HIVAN.

Purpose

We wished to determine the utility of serum and urinary biomarkers in predicting the histological diagnosis of HIVAN.

Patients and Methods

We measured neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, transforming growth factor (TGF)-β isoforms and bone morphogenetic protein (BMP)-7 in the serum and urine in patients with different histological forms of HIV glomerular disease.

Results

In HIVAN, we demonstrated increased levels of serum cystatin C and increased levels of serum and urinary NGAL. Urinary TGF-β1 and TGF-β2 levels were elevated in HIV-positive patients with CKD but were not significantly different in the different HIV histologies, while urinary BMP-7 levels were elevated in minimal change disease.

Conclusion

This study confirmed the presence of increased serum and urinary biomarkers of tubular injury in patients with HIVAN, and increased urinary biomarkers of fibrosis in HIV CKD, and may indicate their value as a non-invasive diagnostic tool for the diagnosis of HIVAN.

Viral Nephropathies, Adding SARS-CoV-2 to the List

Viral infections in the immunocompetent host can cause both acute and chronic kidney disease either as a direct damage to the infected kidney cells or as a consequence of systemic immune responses that impact kidney function. Since identifying these entities in the 1970s and 80s, major breakthroughs in the understanding of the viral mechanisms have occurred. Viruses have evolved mechanisms to hijack signaling pathways of infected cells to evade antiviral immune responses by the host. Over time, the clinical presentations and management of these diseases have evolved along with our in-depth understanding of the various pathophysiological mechanisms causing these conditions. Similarly, both at the cellular and systemic levels, the host has evolved mechanisms to counter viral subversion strategies for mutual survival. Since the start of the current COVID-19 pandemic, numerous cases of acute kidney injury have been reported in the literature with various possible pathophysiological mechanisms. In this review, we summarize lessons learned from prior viral pandemics related to viral mechanisms utilized in the pathogenesis of numerous renal manifestations to attempt to utilize this knowledge in predicting post-COVID-19 kidney disease.

Chronic Kidney Disease Risk in African and Caribbean Populations With HIV

We conducted an observational cohort study of end-stage kidney disease (ESKD) in >7000 African and Caribbean people with HIV in the UK. Using Poisson regression and East Africans as the reference group, the adjusted incidence rate ratio (95% confidence interval) of ESKD was 3.14 (1.26–7.84) in Southern Africans, 6.35 (2.53–15.96) in West Africans, and 5.26 (1.91–14.43) in Caribbeans. Higher CD4 cell count and suppressed HIV replication were associated with reduced risk of ESKD. The risk of ESKD varied among HIV-positive people of African heritage, with the highest rates observed in those of West African descent.

Clinical characteristics and outcome of HIV infected patients with chronic kidney disease in Sub Saharan Africa: an example from in Cameroon

BACKGROUND

Chronic kidney disease (CKD) is one of the major complications of Human immune deficiency Virus (HIV) and a risk factor for poor outcome of these patients. We aimed to describe the profile and outcome of HIV positive patients with CKD in Douala general hospital in Cameroon.

METHODS

HIV positive patients with CKD referred to the nephrologist from January 2007 to March 2013 were included. Socio demographic, clinical (history and stage of HIV, comorbidities, baseline nephropathy, used of c-ART), para clinical data at referral (serum urea, creatinine, full blood count, CD4 count, serum calcium, phosphorus, albumin), dialysis initiation and outcome at 1 year were collected from medical records. GFR was estimated using Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. CKD was defined and classified according to the Kidney Disease Improving Global Outcomes (KDIGO 2012).

RESULTS

We included 156 patients (51.3% men) with a mean age of 45.4 ± 12.1 years. Hypertension (36.5%), diabetes (17.9%) and Hepatitis C (7.7%) were the main comorbidities. HIV associated nephropathy (27.6%), chronic glomerulonephritis (15.4%) diabetes (14.1%) and hypertension (13.5%) were the leading causes of kidney disease. Before referral HIV status was known by 109 (69.9%) patients, with 76 (69.7%) being on c-ART. Median CD4 count was 241 (117-438) cells/mm3. Prevalence of anemia (93.9%), hypocalcemia (68.6%) and Proteinuria (77.6%) was high, 94 (60.3%) patients were at CKD stage 5 at referral and 37 (23.7%) underwent emergency dialysis. After 1 year, 64 (41.0%) patients were lost to follow up. The mortality rate was 49% and 25 (28.7%) were maintenance hemodialysis, and being on c-ART was associated with a lower risk of death (HR: 0.45; 95% CI: 0.23-0.89; p = 0.021).

CONCLUSION

HIV patients with CKD were referred late with high morbidity and need for urgent hemodialysis. HIVAN was the main etiology of CKD and mortality rate was high mainly due to the absence of c-ART at referral.

Kidney disease in Africans with HIV and tuberculosis

OBJECTIVE

To describe the spectrum of kidney disease in African patients with HIV and tuberculosis (TB).

METHODS

We used data from three cohorts: consecutive patients with HIV/TB in South London (UK, 2004-2016; n = 95), consecutive patients with HIV/TB who underwent kidney biopsy in Cape Town (South Africa, 2014-2017; n = 70), and consecutive patients found to have HIV/TB on autopsy in Abidjan (Cote d'Ivoire, 1991; n = 100). Acute kidney injury (AKI) was ascertained using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. In the Cape Town cohort, predictors of recovery of kidney function at 6 months were assessed using Cox regression.

RESULTS

In the London cohort, the incidence of moderate/severe AKI at 12 months was 15.1 (95% CI 8.6-26.5) per 100 person-years, and the prevalence of chronic and end-stage kidney disease (ESKD) 13.7 and 5.7%, respectively. HIV-associated nephropathy (HIVAN) was diagnosed in 6% of patients in London, and in 6% of autopsy cases in Abidjan. Evidence of renal TB was present in 60% of autopsies in Abidjan and 61% of kidney biopsies in Cape Town. HIVAN and acute tubular necrosis (ATN) were also common biopsy findings in Cape Town. In Cape Town, 40 patients were dialyzed, of whom 28 (70%) were able to successfully discontinue renal replacement therapy. Antiretroviral therapy status, CD4 cell count, estimated glomerular filtration rate (eGFR) at biopsy and renal histology, other than ATN, were not predictive of eGFR recovery.

CONCLUSION

Kidney disease was common in Africans with HIV/TB. Monitoring of kidney function, and provision of acute dialysis to those with severe kidney failure, is warranted.

Autoimmune Kidney Diseases Associated with Chronic Viral Infections

Autoimmune kidney diseases triggered by viruses are an important cause of kidney disease in patients affected by chronic viral infection. Hepatitis B virus (HBV) infection is associated with membranous nephropathy and polyarteritis nodosa. Hepatitis C virus (HCV) infection is a major cause of cryoglobulinemic glomerulonephritis. Patients with human immunodeficiency virus (HIV) may develop HIV-associated nephropathy, a form of collapsing focal segmental glomerulosclerosis, or various forms of immune-complex-mediated kidney diseases. This article summarizes what is known about the pathogenesis, diagnosis, and management of immune-mediated kidney diseases in adults with chronic HBV, HCV, and HIV infections.

HIV-associated nephropathy: links, risks and management

Despite the decreased incidence of human immunodeficiency virus (HIV)-associated nephropathy due to the widespread use of combined active antiretroviral therapy, it remains one of the leading causes of end-stage renal disease (ESRD) in HIV-1 seropositive patients. Patients usually present with low CD4 count, high viral load and heavy proteinuria, with the pathologic findings of collapsing focal segmental glomerulosclerosis. Increased susceptibility exists in individuals with African descent, largely due to polymorphism in APOL1 gene. Other clinical risk factors include high viral load and low CD4 count. Advanced kidney disease and nephrotic range proteinuria have been associated with progression to ESRD. Improvement in kidney function has been observed after initiation of combined active antiretroviral therapy. Other treatment options, when clinically indicated, are inhibition of the renin-angiotensin system and corticosteroids. Further routine management approaches for patients with chronic kidney disease should be implemented. In patients with progression to ESRD, kidney transplant should be pursued, provided that viral load control is adequate. Screening for the presence of kidney disease upon detection of HIV-1 seropositivity in high-risk populations is recommended.

HIV and chronic kidney disease

Chronic kidney disease (CKD) is a frequent complication of HIV infection, occurring in 3.5 - 48.5%, and occurs as a complication of HIV infection, other co-morbid disease and infections and as a consequence of therapy of HIV infection and its complications. The classic involvement of the kidney by HIV infection is HIV-associated nephropathy (HIVAN), occurring typically in young adults of African ancestry with advanced HIV disease in association with APOL1 high-risk variants. HIV-immune complex disease is the second most common diagnosis obtained from biopsies of patients with HIV-CKD. CKD is mediated by factors related to the virus, host genetic predisposition and environmental factors. The host response to HIV infection may influence disease phenotype through activation of cytokine pathways. With the introduction of antiretroviral therapy (ART), there has been a decline in the incidence of HIVAN, with an increasing prevalence of focal segmental glomerulosclerosis. Several studies have demonstrated the overall improvement in kidney function when initiating ART for HIV CKD. Progression to end stage kidney disease has been reported to be more likely when high grade proteinuria, severely reduced eGFR, hepatitis B and/C co-infection, diabetes mellitus, extensive glomerulosclerosis, and chronic interstitial fibrosis are present. Improved renal survival is associated with use of renin angiotensin system blockers and viral suppression. Many antiretroviral medications are partially or completely eliminated by the kidney and require dose adjustment in CKD. Certain drug classes, such as the protease inhibitors and the non-nucleoside reverse transcriptase inhibitors, are metabolized by the liver and do not require dose adjustment. HIV-infected patients requiring either hemo- or peritoneal dialysis, who are stable on ART, are achieving survival rates comparable to those of dialysis patients without HIV infection. Kidney transplantation has been performed successfully in HIV-infected patients; graft and patient survival appears to be similar to that of HIV-uninfected recipients. Early detection of kidney disease by implementation of screening on diagnosis of HIV infection and annual screening thereafter will have an impact on the burden of disease, together with access to ART to those who require it. Programs for prevention of HIV infection are essential to prevent this lethal disease.

Clinical characteristics and outcomes of HIV-associated immune complex kidney disease

BACKGROUND

The pathogenesis and natural history of HIV-associated immune complex kidney disease (HIVICK) is not well understood. Key questions remain unanswered, including the role of HIV infection and replication in disease development and the efficacy of antiretroviral therapy (ART) in the prevention and treatment of disease.

METHODS

In this multicentre study, we describe the renal pathology of HIVICK and compare the clinical characteristics of patients with HIVICK with those with IgA nephropathy and HIV-associated nephropathy (HIVAN). Poisson regression models were used to identify risk factors for each of these pathologies.

RESULTS

Between 1998 and 2012, 65 patients were diagnosed with HIVICK, 27 with IgA nephropathy and 70 with HIVAN. Black ethnicity and HIV RNA were associated with HIVICK, receipt of ART with IgA nephropathy and black ethnicity and CD4 cell count with HIVAN. HIVICK was associated with lower rates of progression to end-stage kidney disease compared with HIVAN and IgA nephropathy (P < 0.0001). Patients with HIVICK who initiated ART and achieved suppression of HIV RNA experienced improvements in estimated glomerular filtration rate and proteinuria.

CONCLUSIONS

These findings suggest a pathogenic role for HIV replication in the development of HIVICK and that ART may improve kidney function in patients who have detectable HIV RNA at the time of HIVICK diagnosis. Our data also suggest that IgA nephropathy should be viewed as a separate entity and not included in the HIVICK spectrum.

Renal Transplantation in HIV-Infected Patients: The First Portuguese Review

INTRODUCTION

With the introduction of combination antiretroviral therapy (cART), prognosis of human immunodeficiency virus (HIV) infection has been improved and kidney transplantation (KT) in HIV-positive patients became possible.

METHODS

We reviewed the demographic, clinical, laboratory, and therapeutic data of all the HIV-infected patients who underwent KT between 2009 (first KT in Portugal in a HIV-infected patient) and May 2014. Case accrual was through all Portuguese KT centers where a KT in an HIV-infected patient was performed. Patients were transplanted following the American and Spanish guideline recommendations that included maintenance on cART, undetectable plasma HIV RNA copies, and absolute CD4 counts of ≥ 200 cells/μL in the last 6 months.

RESULTS

Fourteen KT were performed on men and 3 on women. The mean age of patients at the time of transplantation was 49.9 ± 11.7 years. HIV status was known for 12 ± 5 years. Eight patients had AIDS in the past and all patients received grafts from deceased donors. Twelve patients (64.7%) underwent induction therapy with basiliximab and 2 patients experienced early graft loss. In 2 patients, humoral rejection was diagnosed and in 3 patients, cellular rejection. Two patients died and an additional patient had early graft loss.

CONCLUSION

KT is a possible, but challenging, renal replacement therapy in selected HIV-positive patients. Even in those with AIDS criteria in the past, when the disease is controlled, and after the reconstitution of the immune system with cART, KT can be performed. Nevertheless, the risk-benefit ratio for each patient needs to be taken in consideration.

HIV and the kidney in the acute medical unit

Acute kidney injury (AKI) is encountered commonly in HIV-positive patients admitted to the acute medical unit. The spectrum of AKI has changed in the era of combination anti-retroviral therapy, and now includes adverse effects of commonly used anti-retroviral drugs in addition to traditional precipitants such as severe sepsis or exposure to nephrotoxic antimicrobials. An accurate diagnosis requires careful integration of clinical data including volume status, history of potentially nephrotoxic exposures and consideration of immuno-virological status. This article provides an overview of common causes of AKI in HIV and presents a framework by which the acute care physician may approach the finding of an elevated serum creatinine in a patient with HIV.

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.

Incidence and risk factors for tenofovir-associated renal toxicity in HIV-infected patients

BACKGROUND

Since the beginning of highly active antiretroviral therapy utilization, the association of renal impairment with treatment toxicity is more prevalent. Tenofovir disoproxil fumarate (TDF) side effects include renal toxicity.

OBJECTIVE

To assess the incidence of renal damage in human immunodeficiency virus (HIV)-positive patients treated with TDF and to identify associated potential risk factors.

SETTING

A public university tertiary 450-beds hospital in Spain.

METHOD

Retrospective, longitudinal observational study that included adult HIV-1-infected patients treated with TDF. Patient´s treated with TDF from January 2010 to December 2012 were included. Patient follow-up started when initiating treatment with TDF up until either end of treatment or end of study (July 31, 2013). The estimated glomerular filtration rate was calculated using the four-variable modification of diet in renal disease. Renal toxicity was classified as moderate [estimated glomerular filtration rate (eGFR) < 60 ml/min] or severe (eGFR < 30 ml/min). The incidence rate for moderate and severe renal insufficiency was calculated as number of cases per 1000 patient-year. A univariate analysis and binary logistic regression was carried out in order to identify risk factors associated with renal toxicity by using the forward stepwise method (likelihood ratio)

MAIN OUTCOME MEASURE

Incidence rate for moderate and severe renal insufficiency (RI) RESULTS: 451 patients were included in the study. The incidence rate of moderate RI was 29.2 cases per 1000 person-year (95% CI 22.1-36.3), whereas the incidence of severe RI was 2.2 cases per 1000 person-year (95% CI 0.3-4.1). Multivariate analysis confirmed an independent association with the risk of kidney damage for age (OR 1.08 95% CI 1.05-1.12), time on treatment with TDF (OR 1.16 95% CI 1.04-1.30), baseline creatinine (OR 49.80 95% CI 7.90-311.92) and treatment with NNRTIs (OR 0.45 95% CI 0.24-0.83).

CONCLUSION

Mild to moderate renal failure is a frequent complication during treatment with TDF although severe renal impairment is scarce. Risk factors include age, duration of treatment with TDF, elevated baseline creatinine levels, and treatment with protease inhibitor boosted with ritonavir combinations.

Monitoring of kidney function in HIV-positive patients

HIV-positive patients are at increased risk of developing chronic kidney disease. Although guidelines recommend regular monitoring of renal function in individuals living with HIV, the optimal frequency remains to be defined. In this review, we discuss the renal syndromes that may be identified at an earlier stage via routine assessment of kidney function, and provide guidance in terms of the frequency of monitoring, the most useful tests to perform, and their clinical significance. Specifically, we address whether annual monitoring of kidney function is appropriate for the majority of HIV-positive patients.

African origins and chronic kidney disease susceptibility in the human immunodeficiency virus era

Chronic kidney disease (CKD) is a major public health problem worldwide with the estimated incidence growing by approximately 6% annually. There are striking ethnic differences in the prevalence of CKD such that, in the United States, African Americans have the highest prevalence of CKD, four times the incidence of end stage renal disease when compared to Americans of European ancestry suggestive of genetic predisposition. Diabetes mellitus, hypertension and human immunodeficiency virus (HIV) infection are the major causes of CKD. HIV-associated nephropathy (HIVAN) is an irreversible form of CKD with considerable morbidity and mortality and is present predominantly in people of African ancestry. The APOL1 G1 and G2 alleles were more strongly associated with the risk for CKD than the previously examined MYH9 E1 risk haplotype in individuals of African ancestry. A strong association was reported in HIVAN, suggesting that 50% of African Americans with two APOL1 risk alleles, if untreated, would develop HIVAN. However these two variants are not enough to cause disease. The prevailing belief is that modifying factors or second hits (including genetic hits) underlie the pathogenesis of kidney disease. This work reviews the history of genetic susceptibility of CKD and outlines current theories regarding the role for APOL1 in CKD in the HIV era.

HIV-associated nephropathies: epidemiology, pathology, mechanisms and treatment

HIV is a highly adaptive, rapidly evolving virus, which is associated with renal diseases including collapsing glomerulopathy-the classic histomorphological form of HIV-associated nephropathy. Other nephropathies related to viral factors include HIV-immune-complex kidney disease and thrombotic microangiopathy. The distribution of HIV-associated kidney diseases has changed over time and continues to vary across geographic regions worldwide. The reasons for this diversity are complex and include a critical role of APOL1 variants and possibly other genetic factors, disparities in access to effective antiviral therapies, and likely other factors that we do not yet fully understand. The mechanisms responsible for HIVAN, including HIV infection of podocytes and tubular epithelial cells, the molecules responsible for HIV entry, and diverse mechanisms of cell injury, have been the focus of much study. Although combined antiretroviral therapy is effective at preventing and reversing HIVAN, focal segmental glomerulosclerosis, arterionephrosclerosis and diabetic nephropathy are increasingly common in individuals who have received such therapy for many years. These diseases are associated with metabolic syndrome, obesity and premature ageing. Future directions for HIV-related kidney disease will involve regular screening for drug nephrotoxicity and incipient renal disease, as well as further research into the mechanisms by which chronic inflammation can lead to glomerular disease.

Clinical practice guideline for the management of chronic kidney disease in patients infected with HIV: 2014 update by the HIV Medicine Association of the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Modulation of renin angiotensin system predominantly alters sclerotic phenotype of glomeruli in HIVAN

HIV-associated nephropathy (HIVAN) is a common complication of HIV-1 infection in patients with African ancestry in general and with APOL1 gene risk variants in particular. Although collapsing glomerulopathy is considered a hallmark of HIVAN, significant numbers of glomeruli in patients with HIVAN also display other variants of focal segmental glomerulosclerosis (FSGS). We propose that collapsed glomeruli as well as glomeruli with other variants of FSGS are manifestations of HIVAN and their prevalence depends on associated host factors. We explored the role of the renin-angiotensin system (RAS) in the manifestation of any specific glomerular phenotype in HIVAN. To evaluate the role of the RAS we have used a genetically engineered mouse model of HIVAN (Tg26) with two and four copies of angiotensinogen (Agt) gene (Tg26/Agt2 and Tg26/Agt4). In Tg26/Agt2, 1 out of 6 glomeruli exhibited sclerosed phenotype, whereas 1 out of 25 glomeruli displayed collapsed phenotype; on the other hand, in Tg26/Agt4, 1 out of 3 glomeruli exhibited sclerotic phenotype and only 1 out of 7 glomeruli showed collapsed phenotype. To inhibit the effect of RAS, Tg26/Agt2 were administered captopril, aliskiren, aliskiren plus captopril or aliskiren plus telmisartan by miniosmotic pumps for 4 weeks. In all experimental groups there was a significant reduction in percentage of sclerosed glomeruli and only minimal reduction in collapsed glomeruli compared to normal saline receiving Tg26/Agt2. These findings suggest that the manifestation of the sclerosed phenotype in HIVAN is predominantly dependent on activation of the RAS.

Impact of antiretroviral therapy on renal function among HIV-infected Tanzanian adults: a retrospective cohort study

Background

Data regarding the outcomes of HIV-infected adults with baseline renal dysfunction who start antiretroviral therapy are conflicting.

Methods

We followed up a previously-published cohort of HIV-infected adult outpatients in northwest Tanzania who had high prevalence of renal dysfunction at the time of starting antiretroviral therapy (between November 2009 and February 2010). Patients had serum creatinine, proteinuria, microalbuminuria, and CD4⁺ T-cell count measured at the time of antiretroviral therapy initiation and at follow-up. We used the adjusted Cockroft-Gault equation to calculate estimated glomerular filtration rates (eGFRs).

Results

In this cohort of 171 adults who had taken antiretroviral therapy for a median of two years, the prevalence of renal dysfunction (eGFR <90 mL/min/1.73 m²) decreased from 131/171 (76.6%) at the time of ART initiation to 50/171 (29.2%) at the time of follow-up (p<0.001). Moderate dysfunction (eGFR<60 mL/min/1.73 m²) decreased from 21.1% at antiretroviral therapy initiation to 1.1% at follow-up (p<0.001), as did the prevalence of microalbuminuria (72% to 44%, p<0.001). Use of tenofovir was not associated with renal dysfunction at follow-up.

Conclusion

Mild and moderate renal dysfunction were common in this cohort of HIV-infected adults initiating antiretroviral therapy, and both significantly improved after a median follow-up time of 2 years. Our work supports the renal safety of antiretroviral therapy in African adults with mild-moderate renal dysfunction, suggesting that these regimens do not lead to renal damage in the majority of patients and that they may even improve renal function in patients with mild to moderate renal dysfunction.

Kidney transplantation in HIV-positive adults: the UK experience

HIV-positive patients are at increased risk of end-stage kidney disease (ESKD). Kidney transplantation (KT) is an established treatment modality for ESKD in the general population. Recent data have confirmed the feasibility of kidney transplantation in HIV-positive patients, and kidney transplantation is increasingly offered to ESKD patients with well-controlled HIV infection. We report clinical outcomes in a national cohort study of kidney transplantation in HIV-positive patients. In all, 35 HIV-positive KT recipients who had undergone KT up to December 2010 (66% male, 74% black ethnicity) were identified; the median CD4 cell count was 366, all had undetectable HIV RNA levels at kidney transplantation, and 44% received a kidney from a live donor. Patient survival at 1 and 3 years was 91.3%, and graft survival 91.3% and 84.7%, respectively. At one-year post-kidney transplantation, the cumulative incidence of acute rejection was 48%, and the median (IQR) eGFR was 64 (46, 78) mL/min/1.73 m(2). Although HIV viraemia and HIV disease progression were uncommon, renal complications were relatively frequent. Our study corroborates the feasibility of kidney transplantation in HIV-positive patients. The high rates of acute rejection suggest that the optimal immune suppression strategy in this population remains to be refined.

HIV-associated nephropathy in Saudi Arabia

BACKGROUND AND OBJECTIVES

Human immunodeficiency virus-associated nephropathy (HIVAN) is the most common cause of chronic renal failure in HIV patients with African descent. It usually presents with proteinuria, enlarged kidneys, and rapidly progressive renal failure, often over several weeks to months. We conducted this study to determine the prevalence of HIVAN in our HIV population.

DESIGN AND SETTINGS

Cross-sectional observational study in a referral center covering the period of 1990- 2010.

METHODS

Proteinuria and estimated glomerular filtration rate (e-GFR) were used to identify renal disease and suspicious cases of HIVAN with abnormal proteinuria and e-GFR of < 60 mL/min/1.73 m2.

RESULTS

Of 585 HIV-positive patients, 248 were eligible to inclusion criteria. Most of the patients were male, that is, 165 (67%) were male compared to 83 (33%) female with the mean age 39 years; 240 (96.7%) were on antiretroviral therapy. Thirty (12%) patients had abnormal proteinuria and 218 (88%) had normal urinary protein and e-GFR. No significant differences were observed in demographic data, CD4+ T-lymphocyte count, viral load, creatinine level, and e-GFR among both groups. Significant differences were observed in the prevalence of diabetes mellitus in the abnormal proteinuria group (10 patients [33.3%] compared to 30 patients [13.8%] in the normal group (P=.0139) and the prevalence of hypertension in the abnormal proteinuria group (11 patients [36.7%] compared to 22 patients [10%] in the normal group (P=.002). Sixteen patients (6.6% of the cohort) met the study definition of HIVAN.

CONCLUSION

The prevalence of abnormal proteinuria and HIVAN among HIV-infected patients in Saudi Arabia is higher than that of non-African patients in developed countries.

High prevalence of renal dysfunction and association with risk of death amongst HIV-infected Ghanaians

OBJECTIVES

To determine the prevalence of HIV-associated renal dysfunction (RD), identify risk factors for RD and explore the association between baseline renal function and mortality in an HIV-infected population in Ghana.

METHODS

Creatinine clearance (CrCl) or estimated glomerular filtration rate (eGFR) was calculated in patients attending an HIV clinic between 2004 and 2011 using Cockcroft-Gault, MDRD and CKD-EPI formulae. Logistic regression analysis was used to identify risk factors associated with RD and Kaplan-Meier/Cox proportional regression analyses to explore associations between baseline CrCl/eGFR and subsequent mortality.

RESULTS

In 3137 patients starting antiretroviral therapy (ART) the frequency (95%-CI) of RD, defined by CrCl <60 ml/min/1.73 m(2) using Cockroft-Gault formula was 38.8% (37.1-40.5%). RD prevalence in a sub-population of 238 patients, including proteinuria in the definition, was 15.3% (10.3-22.1%) in ART-treated and 43.6% (34.0-53.7%) in ART-naïve patients. RD at baseline was associated with increasing age, low CD4 counts, advanced WHO stage and female gender. Cox proportional hazard analysis identified an increased hazard of death with decreasing CrCl, HR 1.46 (1.31-1.63) for each tertile lower than CrCl of 90 ml/min/1.73 m(2).

CONCLUSIONS

RD is very common in HIV-infected ART-naïve Ghanaians, and associated with increased risk of mortality. Screening and monitoring of RD is important in this setting, particularly as tenofovir use increases.

Renal AA-amyloidosis in intravenous drug users--a role for HIV-infection?

Background

Chronic renal disease is a serious complication of long-term intravenous drug use (IVDU). Recent reports have postulated a changing pattern of underlying nephropathy over the last decades.

Methods

Retrospective investigation including all patients with prior or present IVDU that underwent renal biopsy because of chronic kidney disease between 01.04.2002 and 31.03.2012 in the city of Frankfurt/Main, Germany.

Results

Twenty four patients with IVDU underwent renal biopsy because of progressive chronic kidney disease or proteinuria. Renal AA-amyloidosis was the predominant cause of renal failure in 50% of patients. Membranoproliferative glomerulonephritis (GN) was the second most common cause found in 21%. Patients with AA-amyloidosis were more likely to be HIV infected (67 vs.17%; p=0.036) and tended to have a higher rate of repeated systemic infections (92 vs. 50%; p=0.069). Patients with AA-amyloidosis presented with progressive renal disease and nephrotic-range proteinuria but most patients had no peripheral edema or systemic hypertension. Development of proteinuria preceded the decline of GFR for approximately 1–2 years.

Conclusions

AA-amyloidosis was the predominant cause of progressive renal disease in the last 10 years in patients with IVDU. The highest rate of AA-amyloidosis observed was seen in HIV infected patients with IVDU. We speculate that chronic HIV-infection as well as the associated immunosuppression might promote development of AA-amyloidosis by increasing frequency and duration of infections acquired by IVDU.

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.

Baseline kidney function as predictor of mortality and kidney disease progression in HIV-positive patients

BACKGROUND

Chronic kidney disease (CKD) is associated with increased all-cause mortality and kidney disease progression. Decreased kidney function at baseline may identify human immunodeficiency virus (HIV)-positive patients at increased risk of death and kidney disease progression.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

7 large HIV cohorts in the United Kingdom with kidney function data available for 20,132 patients.

PREDICTOR

Baseline estimated glomerular filtration rate (eGFR).

OUTCOMES

Death and progression to stages 4-5 CKD (eGFR <30 mL/min/1.73 m(2) for >3 months) in Cox proportional hazards and competing-risk regression models.

RESULTS

Median age at baseline was 34 (25th-75th percentile, 30-40) years, median CD4 cell count was 350 (25th-75th percentile, 208-520) cells/μL, and median eGFR was 100 (25th-75th percentile, 87-112) mL/min/1.73 m(2). Patients were followed up for a median of 5.3 (25th-75th percentile, 2.0-8.9) years, during which 1,820 died and 56 progressed to stages 4-5 CKD. A U-shaped relationship between baseline eGFR and mortality was observed. After adjustment for potential confounders, eGFRs <45 and >105 mL/min/1.73 m(2) remained associated significantly with increased risk of death. Baseline eGFR <90 mL/min/1.73 m(2) was associated with increased risk of kidney disease progression, with the highest incidence rates of stages 4-5 CKD (>3 events/100 person-years) observed in black patients with eGFR of 30-59 mL/min/1.73 m(2) and those of white/other ethnicity with eGFR of 30-44 mL/min/1.73 m(2).

LIMITATIONS

The relatively small numbers of patients with decreased eGFR at baseline and low rates of progression to stages 4-5 CKD and lack of data for diabetes, hypertension, and proteinuria.

CONCLUSIONS

Although stages 4-5 CKD were uncommon in this cohort, baseline eGFR allowed the identification of patients at increased risk of death and at greatest risk of kidney disease progression.

End-stage renal disease and dialysis in HIV-positive patients: observations from a long-term cohort study with a follow-up of 22 years

OBJECTIVES

Renal disease is a common and serious complication in HIV-infected patients.

METHODS

A retrospective cohort analysis for the period 1989-2010 was carried out to determine the prevalence, incidence and risk factors for end-stage renal disease (ESRD). ESRD was defined as initiation of renal replacement therapy. Three time periods were defined: 1989-1996 [pre-highly active antiretroviral therapy (HAART)], 1997-2003 (early HAART) and 2004-2010 (late HAART).

RESULTS

Data for 9198 patients [78.2% male; 88.9% Caucasian; cumulative observation time 68 084 patient-years (PY)] were analysed. ESRD was newly diagnosed in 35 patients (0.38%). Risk factors for ESRD were Black ethnicity [relative risk (RR) 5.1; 95% confidence interval (CI) 2.3-10.3; P < 0.0001], injecting drug use (IDU) (RR 2.3; 95% CI 1.1-4.6; P = 0.02) and hepatitis C virus (HCV) coinfection (RR 2.2; 95% CI 1.1-4.2; P = 0.03). The incidence of ESRD decreased in Black patients over the three time periods [from 788.8 to 130.5 and 164.1 per 100 000 PY of follow-up (PYFU), respectively], but increased in Caucasian patients (from 29.9 to 41.0 and 43.4 per 100 000 PYFU, respectively). The prevalence of ESRD increased over time and reached 1.9 per 1000 patients in 2010. Mortality for patients with ESRD decreased nonsignificantly from period 1 to 2 (RR 0.72; P = 0.52), but significantly from period 1 to 3 (RR 0.24; P = 0.006), whereas for patients without ESRD mortality decreased significantly for all comparisons. ESRD was associated with a high overall mortality (RR 9.9; 95% CI 6.3-14.5; P < 0.0001).

CONCLUSION

As a result of longer survival, the prevalence of ESRD is increasing but remains associated with a high mortality. The incidence of ESRD declined in Black but not in Caucasian patients. IDU and HCV were identified as additional risk factors for the development of ESRD.

Total protein, albumin and low-molecular-weight protein excretion in HIV-positive patients

BACKGROUND

Chronic kidney disease is common in HIV positive patients and renal tubular dysfunction has been reported in those receiving combination antiretroviral therapy (cART). Tenofovir (TFV) in particular has been linked to severe renal tubular disease as well as proximal tubular dysfunction. Markedly elevated urinary concentrations of retinal-binding protein (RBP) have been reported in patients with severe renal tubular disease, and low-molecular-weight proteins (LMWP) such as RBP may be useful in clinical practice to assess renal tubular function in patients receiving TFV. We analysed 3 LMWP as well as protein and albumin in the urine of a sample of HIV positive patients.

METHODS

In a cross-sectional fashion, total protein, albumin, RBP, cystatin C, and neutrophil gelatinase-associated lipocalin (NGAL) were quantified in random urine samples of 317 HIV positive outpatients and expressed as the ratio-to-creatinine (RBPCR, CCR and NGALCR). Exposure to cART was categorised as none, cART without TFV, and cART containing TFV and a non-nucleoside reverse-transcriptase-inhibitor (TFV/NNRTI) or TFV and a protease-inhibitor (TFV/PI).

RESULTS

Proteinuria was present in 10.4 % and microalbuminuria in 16.7 % of patients. Albumin accounted for approximately 10 % of total urinary protein. RBPCR was within the reference range in 95 % of patients while NGALCR was elevated in 67 % of patients. No overall differences in urine protein, albumin, and LMWP levels were observed among patients stratified by cART exposure, although a greater proportion of patients exposed to TFV/PI had RBPCR >38.8 μg/mmol (343 μg/g) (p = 0.003). In multivariate analyses, black ethnicity (OR 0.43, 95 % CI 0.24, 0.77) and eGFR <75 mL/min/1.73 m2 (OR 3.54, 95 % CI 1.61, 7.80) were independently associated with upper quartile (UQ) RBPCR. RBPCR correlated well to CCR (r2 = 0.71), but not to NGALCR, PCR or ACR.

CONCLUSIONS

In HIV positive patients, proteinuria was predominantly of tubular origin and microalbuminuria was common. RBPCR in patients without overt renal tubular disease was generally within the reference range, including those receiving TFV. RBP therefore appears a promising biomarker for monitoring renal tubular function in patients receiving TFV and for distinguishing patients with normal tubular function or mild tubular dysfunction from those with severe renal tubular disease or Fanconi syndrome.

Determinants of incident chronic kidney disease and progression in a cohort of HIV-infected persons with unrestricted access to health care

OBJECTIVES

As socioeconomic factors may impact the risk of chronic kidney disease (CKD), we evaluated the incidence and risk factors of incident CKD among an HIV-infected cohort with universal access to health care and minimal injecting drug use (IDU).

METHODS

Incident CKD was defined as an estimated glomerular filteration rate (eGFR) <60 ml/min/1.73 m(2) for ≥ 90 days. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Rates were calculated per 1000 person-years (PY). Associations with outcomes were assessed using two separate Cox proportional hazard models, adjusting for baseline and time-updated covariates.

RESULTS

Among 3360 participants [median age 29 years; 92% male; 44% African American (AA)] contributing 23,091 PY of follow-up, 116 developed incident CKD [5.0/1000 PY; 95% confidence interval (CI) 4.2-6.0/1000 PY]. The median first eGFR value was 97.0 mL/min/1.73 m(2) [interquartile range (IQR) 85.3-110.1 mL/min/1.73 m(2)]. Baseline factors associated with CKD included older age, lower CD4 count at HIV diagnosis [compared with CD4 count ≥ 500 cells/μL, hazard ratio (HR) 2.1 (95% CI 1.2-3.8) for CD4 count 350-499 cells/μL; HR 3.6 (95% CI 2.0-6.3) for CD4 count 201-349 cells/μL; HR 4.3 (95% CI 2.0-9.4) for CD4 count ≤ 200 cells/μL], and HIV diagnosis in the pre-highly active antiretroviral therapy (HAART) era. In the time-updated model, low nadir CD4 counts, diabetes, hepatitis B, hypertension and less HAART use were also associated with CKD. AA ethnicity was not associated with incident CKD in either model.

CONCLUSIONS

The low incidence of CKD and the lack of association with ethnicity observed in this study may in part be attributable to unique features of our cohort such as younger age, early HIV diagnosis, minimal IDU, and unrestricted access to care. Lower baseline CD4 counts were significantly associated with incident CKD, suggesting early HIV diagnosis and timely introduction of HAART may reduce the burden of CKD.

Chronic kidney disease associated with perinatal HIV infection in children and adolescents

BACKGROUND

This study describes the incidence, clinical and demographic characteristics, and spectrum of chronic kidney disease (CKD) in youths with perinatal HIV-1 infection.

METHODS

Retrospective analysis between May 1993 and December 2006 of subjects with renal disease followed in the Pediatric AIDS Clinical Trials Group 219/219C multicenter study examining the long-term consequences of perinatal HIV infection. Diagnosis confirmation was made utilizing a questionnaire mailed to research sites. Participants with CKD of other etiology than HIV were excluded. Outcome measures were biopsy-diagnosed CKD and, in the absence of biopsy, HIV-associated nephropathy (HIVAN) using established clinical criteria.

RESULTS

Questionnaires on 191 out of 2,102 participants identified 27 cases of CKD: 14 biopsy-diagnosed and 6 clinical cases of HIVAN, and 7 biopsy-diagnosed cases of immune complex-mediated kidney disease (lupus-like nephritis, 3; IgA nephropathy, 2; membranous nephropathy, 2). Incidence rates for CKD associated with HIV in pre-highly active antiretroviral therapy (HAART) (1993-1997) and HAART (1998-2002, 2003-2006) eras were 0.43, 2.84, and 2.79 events per 1,000 person years respectively. In multivariate analysis, black race and viral load ≥100,000 copies/mL (rate ratios 3.28 and 5.05, p ≤ 0.02) were associated with CKD.

CONCLUSIONS

A variety of immune complex-mediated glomerulonephritides and HIVAN occurs in this population. Black race and uncontrolled viral replication are risk factors for CKD associated with HIV.

HIV-associated kidney disease in the context of an aging population

Acute renal failure and chronic kidney disease are more common in HIV-infected patients compared with the general population. Several studies have shown age to be a risk factor for HIV-associated kidney disease. The improved life expectancy of HIV-infected patients as a result of widespread use of antiretroviral therapy has resulted in progressive aging of HIV cohorts in the developed world, and an increased burden of cardiovascular and kidney disease. Consequently, HIV care increasingly needs to incorporate strategies to detect and manage these non-infectious co-morbidities.

Non-AIDS-defining events among HIV-1-infected adults receiving combination antiretroviral therapy in resource-replete versus resource-limited urban setting

OBJECTIVE

To compare incidence and distribution of non-AIDS-defining events (NADEs) among HIV-1-infected adults receiving combination antiretroviral therapy (cART) in urban sub-Saharan African versus United States settings.

DESIGN

Retrospective cohort analysis of clinical trial and observational data.

METHODS

Compared crude and standardized (to US cohort by age and sex) NADE rates from two urban adult HIV-infected cART-initiating populations: a clinical trial cohort in Gaborone, Botswana (Botswana) and an observational cohort in Nashville, Tennessee (USA).

RESULTS

Crude NADE incidence rates were similar: 10.0 [95% confidence interval 6.3-15.9] per 1000 person-years in Botswana versus 12.4 [8.4-18.4] per 1000 person-years in the United States. However, after standardizing to an older, predominantly male US population, the overall NADE incidence rates were higher in Botswana [18.7 (8.3-33.1) per 1000 person-years]. Standardized rates differed most for cardiovascular events (8.4 versus 5.0 per 1000 person-years) and non-AIDS-defining malignancies (8.0 versus 0.5 per 1000 person-years) - both higher in Botswana. Conversely, hepatic NADE rates were higher in the United States (4.0 versus 0.0 per 1000 person-years), whereas renal NADE rates [3.0 per 1000 person-years (United States) versus 2.4 per 1000 person-years (Botswana)] were comparable.

CONCLUSION

Crude NADE incidence rates were similar between cART-treated patients in a US observational cohort and a sub-Saharan African clinical trial. However, when standardized to the US cohort, overall NADE rates were higher in Botswana. NADEs appear to be a significant problem in our sub-Saharan African setting, and the monitoring, prevention, and treatment of NADEs should be a critical component of care in resource-limited settings.

Presentation of HIV-associated nephropathy and outcome in HAART-treated patients

BACKGROUND

Among the numerous renal diseases observed in human immunodeficiency virus (HIV) patients, HIV-associated nephropathy (HIVAN) is a major cause of end-stage renal disease (ESRD). The purpose of our study was to describe the presentation and outcome of HIVAN in the era of highly active antiretroviral therapy (HAART).

METHODS

We analysed clinical features and outcome of 57 patients with histologically proven HIVAN diagnosed between 2000 and 2009 in four teaching hospitals in Paris, France.

RESULTS

This series was characterized by median age of 41 years (18-58), frequent African origin (87%), severe renal dysfunction [estimated glomerular filtration rate (eGFR) 20 mL/min/1.73m(2) (1-68)], high-grade proteinuria [4.1 g/day (0.6-16.8)], high proportion of sclerotic glomeruli [31.5% (0-95)], high HIV load [4.5 log copies/mL (0-6.7)] and low CD4+ count [127/mm(3) (3-713)]. Nevertheless, a non-negligible proportion of patients did not present with these typical features. Follow-up data were available for 51 patients. ESRD occurred in 30 patients (58.8%). Median renal survival was 40 months. Baseline characteristics significantly associated with ESRD were as follows: severity of renal dysfunction, percentage of sclerotic glomeruli, time from HIV infection to HIVAN diagnosis longer than 1 year and prior exposure to antiretroviral drugs. There was an insignificant trend towards better renal outcome being associated with viral suppression during follow-up. Use of renin-angiotensin system (RAS) blockers was associated with higher renal survival (P < 0.05).

CONCLUSION

Despite HAART, HIVAN led to ESRD in more than half of the cases. Early recognition of the disease is crucial to start HAART and RAS blockers before irreversible renal injury.

Advances in our understanding of the pathogenesis of HIV-1 associated nephropathy in children

Childhood HIV-1 associated nephropathy (HIVAN) is a clinical and renal histological disease characterized by heavy proteinuria associated with focal and segmental glomerular sclerosis and/or mesangial hyperplasia in combination with microcystic tubular dilatation. These lesions lead to renal enlargement and rapid progression to kidney failure. Children of African ancestry have a unique susceptibility to developing HIVAN. It is estimated that approximately 300,000 HIV-infected children living in the sub-Saharan Africa could develop HIVAN if they do not receive appropriate antiretroviral therapy. This article discusses recent developments and controversies related to the pathogenesis of childhood HIVAN. The role of host genetic factors, including the newly identified variants in the APOL1 gene, is discussed in the context of previous studies that established the pathological paradigm for HIVAN, and our current understanding of the functional genomics analysis. Hopefully, these advances will provide new research opportunities to generate better treatments for children with HIVAN.

Impact of comorbidities and drug therapy on development of renal impairment in a predominantly African American and Hispanic HIV clinic population

Purpose

Renal impairment in human immunodeficiency virus (HIV)-infected patients could potentially be caused by many factors. HIV-related renal impairment risks have been little studied in African Americans and Hispanics. We investigated the impact of HIV itself, highly active antiretroviral therapy (HAART), comorbidities, and non-HIV-related drug treatment on glomerular filtration rate in a predominantly African American/Hispanic HIV-infected population who had received HAART for at least one year. This study was a retrospective electronic medical record database evaluation of renal impairment risks in a largely African American/Hispanic HIV population obtaining medical care at an HIV clinic in Dallas, Texas.

Methods

Proportional hazards models were used to investigate an association between an estimated glomerular filtration rate decrease >25% from baseline (ie, renal impairment) and demographics, antiretroviral/nonantiretroviral medications, comorbidities (hypertension, diabetes mellitus, hepatitis C virus [HCV] infection, hepatitis B virus [HBV] infection), CD4+ counts, viral load, and duration patients were monitored at the clinic (time on study).

Results

In total, 323 patients were evaluated: 82% males; 61% African American/12% Hispanic/19% Caucasian; mean age 37.9 years (standard deviation [SD] 8.5); 6% HBV-positive; 34% HCV-positive; 29% hypertensive; 3% diabetic; 52% tenofovir-treated; mean weight 75.4 kg (SD, 15.4); mean estimated glomerular filtration 114.5 mL/min/1.73 m² (SD, 36.7) using the Modification of Diet in Renal Disease (MDRD) calculation method; mean creatinine clearance (from which estimated glomerular filtration was extrapolated) by the Cockcroft-Gault calculation method 120.6 mL/min/1.73 m² (SD, 41.2); mean time on study 2.7 years (SD, 1.0 year). An estimated glomerular filtration rate decrease of >25% from baseline was significantly associated with time on study (P = 0.0017; hazards ratio [HR] = 0.999) and hypertension (HR = 1.706; P = 0.0158) by the MDRD method, and with age (HR = 1.039; P = 0.0077), weight (HR = 0.987; P = 0.0023), and time on study (HR = 0.999; P = 0.0043) by extrapolation of Cockcroft-Gault creatinine clearance calculation. No specific HAART agent was associated with significant renal impairment risk by the definition used in this study.

Conclusion

This retrospective database study showed time on study, hypertension, weight, and age to be the only significant predictors of an estimated glomerular filtration rate decrease >25% from baseline.

Immunodeficiency and renal impairment are risk factors for HIV-associated acute renal failure

OBJECTIVE

To identify risk factors for acute renal failure (ARF) in HIV-infected patients.

DESIGN

Observational cohort study of HIV-infected patients attending a South London HIV centre between January 1999 and December 2008.

METHODS

ARF was defined as a transient, more than 40% reduction in renal function as assessed by estimated glomerular filtration rate. Multivariate Poisson regression analysis was used to identify baseline and time-updated factors associated with ARF.

RESULTS

The incidence of ARF was 2.8 (95% confidence interval 2.41-3.24) episodes per 100 person-years. We observed a stepwise increase in ARF incidence with time accrued at lower CD4 cell count and at lower estimated glomerular filtration rate, with adjusted incidence rate ratios of 1 (reference), 1.56 (0.97-2.48), 2.08 (1.11-3.91), 6.38 (3.18-12.78) and 10.29 (5.11-20.98) for CD4 cell counts of more than 350, 201-350, 101-200, 51-100 and of 50/microl or less, and 1 (reference), 1.46 (0.86-2.51), 4.19 (2.37-7.42) and 27.00 (16.13-44.95) for estimated glomerular filtration rate more than 90, 75-89, 60-74 and less than 60 ml/min, respectively. Ethnicity, hepatitis B or C coinfection, exposure to combination antiretroviral therapy with or without indinavir, tenofovir or atazanavir and HIV viraemia were not associated with ARF.

CONCLUSION

Current levels of immunodeficiency and renal function were independent predictors of HIV-associated ARF.

Causes of death in HIV-1-infected patients treated with antiretroviral therapy, 1996-2006: collaborative analysis of 13 HIV cohort studies

BACKGROUND

We examined specific causes of mortality in human immunodeficiency virus type 1 (HIV-1)-infected patients who initiated antiretroviral therapy (ART) in Europe and North America from 1996 through 2006, and we quantified associations of prognostic factors with cause-specific mortality.

METHODS

We retrospectively classified all deaths among 39,272 patients enrolled in 13 HIV-1 cohorts (154,667 person years of follow-up) into the categories specified in the Cause of Death (CoDe) project protocol.

RESULTS

In 1597 (85%) of 1876 deaths, a definitive cause of death could be assigned. Among these, 792 deaths (49.5%) were AIDS related, followed by non-AIDS malignancies (189; 11.8%), non-AIDS infections (131; 8.2%), violence- and/or drug-related causes (124; 7.7%), liver disease (113; 7.0%), and cardiovascular disease (103; 6.5%). Rates of AIDS-related death (hazard ratio [HR] per 100 cell decrease, 1.43; 95% confidence interval [CI], 1.34-1.53) and death from renal failure (HR, 1.73; 95% CI, 1.18-2.55) were strongly inversely related to CD4 count at initiation of ART, whereas rates of death attributable to AIDS (HR for viral load >5 vs 5 log copies/mL, 1.31; 95% CI, 1.12-1.53), infection (HR, 1.85; 95% CI, 1.25-2.73), cardiovascular (HR, 1.54; 95% CI, 1.05-2.27), and respiratory causes (HR, 3.62; 95% CI, 1.30-10.09) were higher in patients with baseline viral load >5 log copies/mL than in other patients. Rates of each cause of death were higher in patients with presumed transmission via injection drug use than in other patients, with marked increases in rates of liver-related (HR for injection drug use vs non-injection drug use, 6.06; 95% CI, 4.03-9.09) and respiratory tract-related (HR, 4.94; 95% CI, 1.96-12.45) mortality. The proportion of deaths classified as AIDS related decreased with increasing duration of ART.

CONCLUSIONS

Important contributors to non-AIDS mortality in treated HIV-1-infected individuals must be addressed if decreases in mortality rates are to continue.

Diagnosis and natural history of HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) is a largely distinctive phenotype induced by HIV-1 infection and is the most recognized and detrimental kidney disease in HIV-infected patients. Host and viral characteristics have been implicated in the pathogenesis of HIVAN that may explain its exclusive predilection to patients of African descent. In untreated patients, the disorder is clinically manifested by an acute decline in kidney function, most often in conjunction with high-grade proteinuria and uncontrolled HIV-1 infection. Histologically, proliferating glomerular epithelial cells are the prominent feature of the disease. Data have evolved over the past decade suggesting that highly active antiretroviral therapy (HAART) can change the natural history of HIVAN, not only by preventing its development but also by halting its progression once developed. Consequently, with the widespread use of HAART, the prevalence of HIVAN is declining in Western countries. In contrast, the epidemiology of the disease is not well defined in the poorest areas in the world, which bear a disproportionate share of the HIV-1 epidemic's burden. Corticosteroids and inhibition of the renin-angiotensin axis are recommended as adjunctive agents in treating patients with established HIVAN and are potentially helpful in delaying the need for renal replacement therapy. However, the long-term value and potential risks of using corticosteroids in this population are unclear.

Gene-gene and gene-environment interactions in HIV-associated nephropathy: A focus on the MYH9 nephropathy susceptibility gene

HIV-associated nephropathy (HIVAN) is a leading cause of ESRD in African Americans. The HIV-1 virus infects podocytes, cells integral to formation of the glomerular filtration barrier, often leading to focal segmental glomerulosclerosis. HIVAN is typically a complication of late-stage HIV infection, associated with low CD4 cell counts and elevated serum HIV RNA levels. Highly active antiretroviral therapy is partially protective and has altered the natural history of HIV-associated kidney disease. Nonetheless, HIVAN remains an important public health concern among HIV-infected African Americans. Although polymorphisms in the MYH9 gene on chromosome 22 are strongly associated with HIVAN, as well as with idiopathic focal segmental glomerulosclerosis and global glomerulosclerosis (historically labeled "hypertensive nephrosclerosis"), the majority of HIV-infected patients who are genetically at risk from MYH9 do not appear to develop severe kidney disease. Therefore, we postulate that additional environmental exposures and/or inherited factors are necessary to initiate human HIVAN. Gene-environment interactions have also been proposed as necessary for the initiation of HIVAN in murine models. It is important that these novel risk factors be identified because prevention of environmental exposures and targeting of additional gene products may reduce the risk for HIVAN, even among those harboring 2 risk alleles in MYH9.

The treatment of HIV-associated nephropathy

Antiretroviral therapy (ART) preserves kidney function in patients with human immunodeficiency virus (HIV)-associated nephropathy (HIVAN). Emerging data also document substantial renal benefits of ART in the general HIV-infected population, which is associated in part with suppression of HIV-1 viral replication. The extent to which the response to ART differs in persons with HIVAN compared with those with other HIV-associated kidney disorders is unknown. Beneficial effects of corticosteroids and angiotensin-converting enzyme inhibitors on kidney function also are suggested by retrospective cohort studies and uncontrolled trials of patients with HIVAN. Underexposure to ART or inadequate ART dosing in HIV-infected patients with CKD may curtail the optimal benefits that may be derived from this therapy.