Recent developments in HIV and the kidney:

Contemporary issues and new challenges in chronic kidney disease amongst people living with HIV

Chronic kidney disease (CKD) is a comorbidity of major clinical significance amongst people living with HIV (PLWHIV) and is associated with significant morbidity and mortality. The prevalence of CKD is rising, despite the widespread use of antiretroviral therapy (ART) and is increasingly related to prevalent non-infectious comorbidities (NICMs) and antiretroviral toxicity. There are great disparities evident, with the highest prevalence of CKD among PLWHIV seen in the African continent. The aetiology of kidney disease amongst PLWHIV includes HIV-related diseases, such as classic HIV-associated nephropathy or immune complex disease, CKD related to NICMs and CKD from antiretroviral toxicity. CKD, once established, is often relentlessly progressive and can lead to end-stage renal disease (ESRD). Identifying patients with risk factors for CKD, and appropriate screening for the early detection of CKD are vital to improve patient outcomes. Adherence to screening guidelines is variable, and often poor. The progression of CKD may be slowed with certain clinical interventions; however, data derived from studies involving PLWHIV with CKD are sparse and this represent an important area for future research. The control of blood pressure using angiotensin converting enzyme inhibitors and angiotensin receptor blockers, in particular, in the setting of proteinuria, likely slows the progression of CKD among PLWHIV. The cohort of PLWHIV is facing new challenges in regards to polypharmacy, drug-drug interactions and adverse drug reactions. The potential nephrotoxicity of ART is important, particularly as cumulative ART exposure increases as the cohort of PLWHIV ages. The number of PLWHIV with ESRD is increasing. PLWHIV should not be denied access to renal replacement therapy, either dialysis or kidney transplantation, based on their HIV status. Kidney transplantation amongst PLWHIV is successful and associated with an improved prognosis compared to remaining on dialysis. As the cohort of PLWHIV ages, comorbidity increases and CKD becomes more prevalent; models of care need to evolve to meet the new and changing chronic healthcare needs of these patients.

COHORT PROFILE: The Complications of Long-Term Antiretroviral Therapy study in Uganda (CoLTART), a prospective clinical cohort

BACKGROUND

Antiretroviral therapy (ART) improves the survival and quality of life of HIV-positive individuals, but the effects of long-term ART use do eventually manifest. The Complications of Long-Term Antiretroviral Therapy cohort study in Uganda (CoLTART) was established to investigate the metabolic and renal complications of long-term ART use among Ugandan adults. We describe the CoLTART study set-up, aims, objectives, study methods, and also report some preliminary cross-sectional study enrolment metabolic and renal complications data analysis results.

METHODS

HIV-positive ART naïve and experienced adults (18 years and above) in Uganda were enrolled. Data on demographic, dietary, medical, social economic and behaviour was obtained; and biophysical measurements and a clinical examination were undertaken. We measured: fasting glucose and lipid profiles, renal and liver function tests, full blood counts, immunology, virology and HIV drug resistance testing. Plasma samples were stored for future studies.

RESULTS

Between July 2013 and October 2014, we enrolled 1095 individuals, of whom 964 (88.0%) were ART experienced (6 months or more), with a median of 9.4 years (IQR 7.0-9.9) on ART. Overall, 968 (88.4%) were aged 35 years and above, 711 (64.9%) were females, 608 (59.6%) were or had ever been on a Tenofovir ART regimen and 236 (23.1%) on a Protease Inhibitor (PI) regimen. There were no differences in renal dysfunction between patients on Tenofovir and Non-Tenofovir containing ART regimens. Patients on PI regimens had higher total cholesterol, lower high density lipoprotein, higher low density lipoprotein, higher triglycerides, and a high atherogenic index for plasma than the non-PI regimen, p = 0.001 or < 0.001. Patients on Non-PI regimens had higher mean diastolic hypertension than patients on PI regimens, p < 0.001.

CONCLUSIONS

Our finding of no differences in renal dysfunction between patients on Tenofovir and those on Non-Tenofovir containing ART regimens means that Tenofovir based first line ART can safely be initiated even in settings without routine renal function monitoring. However, integration of cardiovascular risk assessment, preventive and curative measures against cardiovascular disease are required. The CoLTART cohort is a good platform to investigate the complications of long-term ART use in Uganda.

Renal Function Impairment and Associated Factors among HAART Naïve and Experienced Adult HIV Positive Individuals in Southwest Ethiopia: A Comparative Cross Sectional Study

BACKGROUND

Human immunodeficiency virus (HIV) infection and its treatment cause renal diseases. Renal disease is associated with an increasing cause of morbidity and mortality in HIV positive individuals than in the general population. It has been also associated with adverse outcomes, such as complications of decreased renal functions and progression to renal failure.

OBJECTIVE

To determine the prevalence and factors associated with renal function impairment among highly active antiretroviral therapy (HAART) naive and HAART experienced adult HIV positive individuals.

METHODS

A facility based comparative cross-sectional study was conducted in Jimma University Specialized Hospital (JUSH) from June to September 2014. HIV positive individuals who visited JUSH during the study period were included in the study. Sociodemographic and clinical data were collected using a structured questionnaire. Blood specimen was analyzed for renal function tests. Descriptive statistics, Mann-Whitney U test and logistic regression analysis were done using SPSS version 16 software.

RESULTS

A total of 446 HIV positive individuals, 223 HAART naïve and 223 HAART experienced, were recruited. The overall prevalence of renal function impairment was 18.2% [95%CI: 14.6-21.7]. The prevalence of renal impairment in HAART naive and HAART experienced persons was 28.7% [95%CI: 23.1-34.4] and 7.6% [95%CI: 4.6-11.6], respectively. Age ≥ 50 years (AOR = 3.6; 95% CI 1.4, 9.6), advanced WHO stage (AOR = 2.3; 95% CI 1.1, 4.7), and CD4 count <200 (AOR = 6.9; 95% CI 3.3, 14.2) were independent risk factors among HAART naive participants. Female gender (AOR = 6.6; 95 CI % 1.2, 34), age ≥ 50 years (AOR = 12.1; 95% CI 1.7, 84) and CD4 count <200 (AOR = 17; 95% CI 5.2, 58) were independent risk factors among HAART experienced participants.

CONCLUSION

The prevalence of renal function impairment was higher among HAART naïve than HAART experienced HIV positive individuals. Renal function impairment was associated with disease advancement and old age.

Population-Based Estimates of Life Expectancy After HIV Diagnosis: United States 2008-2011

INTRODUCTION

Using National HIV surveillance system data, we estimated life expectancy and average years of life lost (AYLL) among persons diagnosed with HIV infection during 2008-2011.

METHODS

Population-based surveillance data, restricted to persons with diagnosed HIV infection aged 13 years or older, from all 50 states and Washington, D.C. were used to estimate life expectancy after HIV diagnosis using the life table method. Generated estimates were compared with life expectancy in the general population in the same calendar year to calculate AYLL. Life expectancy and AYLL were also estimated for subgroups by age, sex, and race/ethnicity.

RESULTS

The overall life expectancy after HIV diagnosis in the United States increased by 3.43 years from 25.43 (95% CI: 25.37 to 25.49) in 2008 to 28.86 (95% CI: 28.80 to 28.92) in 2011. Improvements were observed irrespective of sex, race/ethnicity, transmission category, and stage of disease at diagnosis, though the extent of improvement varied by different characteristics. Based on the life expectancy in the general population, in 2010, the AYLL were 12.8 years for males and 16.5 years for females. By race/ethnicity, on average, blacks (13.3 years) and whites (13.4 years) had fewer AYLL than Hispanics/Latinos (14.7).

CONCLUSIONS

Despite improvements in life expectancy among people diagnosed with an HIV infection during 2008-2011, disparities by sex and by race/ethnicity persist. Targeted efforts should continue to further reduce disparities and improve life expectancy after HIV diagnosis.

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.

Strong correlation between protein reagent strip and protein-to-creatinine ratio for detection of renal dysfunction in HIV-infected patients: a cross-sectional study

Background

Tubular dysfunction is common in HIV-infected people and detection of proteinuria is essential to identify this problem. In low-income countries, resources for detection of proteinuria using the Kidney Disease Improve Global Outcomes (KDIGO) gold standard urinary protein/creatinine ratio (uPCR) is rarely possible, and use of the protein reagent strip (PRS) could be an option in these places. The aims of this study were to establish the concordance between PRS and uPCR to detect tubular proteinuria in HIV-infected people, and to assess the sensitivity and specificity of PRS as a diagnostic method in this group.

Methods

A cross-sectional study was conducted to evaluate the correlation between the two techniques to detect protein in urine. Participants were enrolled for a period of 6 months. The measurements were performed in participants who were on highly active antiretroviral therapy (HAART) or prior to the start of treatment. Proteinuria was defined as uPCR ≥ 150 mg/g, and/or ≥ trace on PRS. A phi coefficient was calculated to establish the degree of correlation. We assessed the sensitivity and specificity of PRS compared with uPCR using standard methods.

Results

A total of 799 subjects were included. Of these, 737 (92%) were men. The mean age was 32.9 years (±10.1 years). Most (561, 70%) were on antiretroviral treatment. The mean estimated glomerular filtration rate (eGFR) calculated according to Modification of Diet in Renal Disease (MDRD)-4 was 113.0 mL/min (±22.6). Comorbidities included diabetes mellitus (10, 1.3%) and hypertension (17, 2.1%). The prevalence of proteinuria detected by PRS was 8.3% (n = 66) and by uPCR 10.6% (n = 85). The concordance assessed by phi correlation coefficient was 0.70, p < 0.001, with a sensitivity of 51.7% (95% confidence interval [CI] 41%–62%) and specificity 97% (95% CI 39%–97%).

Conclusions

There is a high concordance between detection of proteinuria by PRS and uPCR. Therefore, in low-income countries PRS can be helpful for detecting tubular damage in people infected with HIV.

A consensus statement on the renal monitoring of Australian patients receiving tenofovir based antiviral therapy for HIV/HBV infection

A number of antiviral agents used against Human Immunodeficiency Virus (HIV) infection and hepatitis B virus (HBV) mono or co-infection have been associated with real nephrotoxicity (including tenofovir disoproxil fumarate (TDF), atazanavir, indinavir and lopinavir) or apparent changes in renal function (e.g. cobicistat, ritonavir, rilpivirine and dolutegravir). Patients with HIV are at higher risk of acute and chronic renal dysfunction, so baseline assessment and ongoing monitoring of renal function is an important part of routine management of patients with HIV.

Given the paucity of evidence in this area, we sought to establish a consensus view on how routine monitoring could be performed in Australian patients on ART regimens, especially those involving TDF. A group of nephrologists and prescribers (an HIV physician and a hepatologist) were assembled by Gilead to discuss practical and reasonable renal management strategies for patients particularly those on TDF-based combination regimens (in the case of those with HIV-infection) or on TDF-monotherapy (in the case of HBV-mono infection). The group considered which investigations should be performed as part of routine practice, their frequency, and when specialist renal referral is warranted. The algorithm presented suggests testing for serum creatinine along with plasma phosphate and an assessment of urinary protein (rather than albumin) and glucose.

Here we advocate baseline tests of renal function at initiation of therapy. If creatinine excretion inhibitors (e.g. cobicistat or rilpivirine) are used as part of the ART regimen, we suggest creatinine is rechecked at 4 weeks and this value used as the new baseline. Repeat testing is suggested at 3-monthly intervals for a year and then at least yearly thereafter if no abnormalities are detected. In patients with abnormal baseline results, renal function assessment should be performed at least 6 monthly. In HBV mono-infected patients advocate that a similar testing protocol may be logical.

Antiretrovirals and the kidney in current clinical practice: renal pharmacokinetics, alterations of renal function and renal toxicity

Assessment of renal function in HIV-positive patients is of increasing importance in the context of ageing and associated comorbidities. Exposure to nephrotoxic medications is widespread, and several commonly used antiretroviral drugs have nephrotoxic potential. Moreover, specific antiretrovirals inhibit renal tubular transporters resulting in the potential for drug-drug interactions as well as increases in serum creatinine concentrations, which affect estimates of glomerular filtration rate in the absence of changes in actual glomerular filtration rate. This review explores the effects of antiretroviral therapy on the kidney and offers an understanding of mechanisms that lead to apparent and real changes in renal function.

Cobicistat: a Novel Pharmacoenhancer for Co-Formulation with HIV Protease and Integrase Inhibitors

Human immunodeficiency virus (HIV) therapy has evolved over the last 20 years from mono-drug therapy given five times daily to regimens consisting of three or four drugs combined in a single-tablet dosed once daily. To allow once-daily administration, several drugs require pharmacokinetic boosting by a concomitantly administered P-glycoprotein and cytochrome P450 inhibitor such as ritonavir. The availability of cobicistat provides an alternative to ritonavir to those who are intolerant to this drug, and the opportunity for co-formulated single-tablet regimens consisting of tenofovir/emtricitabine, cobicistat and elvitegravir, atazanavir or darunavir. The cobicistat/elvitegravir-based regimen is well tolerated and patients achieved high rates of HIV RNA suppression in clinical trials. Cobicistat inhibits renal tubular secretion of creatinine, resulting in increased serum creatinine concentrations and reduced estimated glomerular filtration rate, with a new set point reached after 4 weeks. Treatment limiting renal toxicity with cobicistat/elvitegravir and tenofovir disoproxil fumarate is infrequent and may be further reduced when cobicistat is co-formulated with tenofovir alafenamide fumarate, a novel formation of tenofovir currently undergoing clinical trials.

Renal impairment is associated with coronary heart disease in HIV-positive men

BACKGROUND

Chronic kidney disease is a risk factor for coronary heart disease (CHD). The association between renal impairment and CHD in HIV-positive patients remains poorly described.

OBJECTIVE

To describe the CHD incidence in a cohort of HIV-positive patients and to examine the relationship between reduced estimated glomerular filtration rate (eGFR) and incident CHD.

METHODS

We studied 7,828 HIV-positive patients who were followed up at 3 South London clinics between January 2004 and December 2009. CHD events were identified from electronic records and through elevated troponin levels. Multivariate Poisson regression analysis was used to identify factors associated with CHD among HIV-positive men.

RESULTS

The incidence of CHD among men was 1.2 (95% CI, 0.8-1.8) per 1,000 person-years of follow-up, with 28 patients (0.4%) having experienced 32 CHD events. In adjusted analyses, older age (incidence rate ratios [IRR], 2.81; 95% CI, 1.51-5.25) and hepatitis C virus (HCV) status (IRR, 3.94; 95% CI, 1.00-15.5) were significantly associated with CHD. Although eGFR as a continuous variable was not associated with CHD, an eGFR <75 mL/min remained associated with incident CHD (IRR, 4.30; 95% CI, 1.33-14.5) after adjustment for age. No association between CHD and abacavir exposure was observed (IRR, 0.94; 95% CI, 0.30-2.99).

CONCLUSIONS

The incidence of CHD in this ethnically diverse cohort was low. Our data suggest that impaired renal function identifies patients at increased risk of CHD events in whom management of traditional CHD risk factors should be prioritized.

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.

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.

Glomerular dysfunction and associated risk factors over 4-5 years following antiretroviral therapy initiation in Africa

BACKGROUND

The aim of this study was to investigate long-term renal function in HIV-infected adults initiating antiretroviral therapy (ART) with a CD4(+) T-cell count < 200 cells/mm³ in Africa.

METHODS

This was an observational analysis within the DART trial randomizing 3,316 adults to routine laboratory and clinical monitoring (LCM) or clinically driven monitoring (CDM). Serum creatinine was measured pre-ART (all ≤ 360 μmol/l), at weeks 4 and 12, then every 12 weeks for 4-5 years; estimated glomerular filtration rate (eGFR) was determined using the Cockcroft-Gault formula. We analysed eGFR changes, and cumulative incidences of eGFR< 30 ml/min/1.73 m² and chronic kidney disease (CKD; <60 ml/min/1.73 m² or 25% decrease if <60 ml/min/1.73 m² pre-ART; confirmed >3 months).

RESULTS

At ART initiation, median CD4(+) T-cell count was 86 cells/mm³; 1,492 (45%) participants had mild (60-< 90 ml/min/1.73 m²), 237 (7%) moderate (30-<60 ml/min/1.73 m² and 7 (0.2%) severe (15-<30 ml/min/1.73 m²) decreases in eGFR. First-line ART was zidovudine/lamivudine plus tenofovir (74%), abacavir (9%) or nevirapine (17%). By 4 years, cumulative incidence of eGFR<30 ml/min/1.73 m² was 2.8% (n=90) and CKD was 5.0% (n=162). Adjusted eGFR increases to 4 years were 1, 9 and 6 ml/min/1.73 m² with tenofovir, abacavir and nevirapine, respectively (P<0.001), and 4 and 2 ml/min/1.73 m² for LCM and CDM, respectively (P=0.005; 2 and 3 ml/min/1.73 m² to 5 years; P=0.81).

CONCLUSIONS

On all regimens and monitoring strategies, severe eGFR impairment was infrequent; differences in eGFR changes were small, suggesting that first-line ART, including tenofovir, can be given safely without routine renal function monitoring.

Simultaneous measurement of urinary albumin and total protein may facilitate decision-making in HIV-infected patients with proteinuria

OBJECTIVE

We recently showed that a urine albumin/total protein ratio (uAPR) <0.4 identifies tubular pathology in proteinuric patients. In tubular disorders, proteinuria is usually of low molecular weight and contains relatively little albumin. We tested the hypothesis that uAPR is useful in identifying tubular pathology related to antiretroviral use in HIV-infected patients.

METHODS

We retrospectively identified urine protein/creatinine ratios (uPCRs) in HIV-infected patients. A subset of samples had uPCR and urine albumin/creatinie ratio (uACR) measured simultaneously. We classified proteinuric patients (uPCR >30 mg/mmol) into two groups: those with predominantly 'tubular' proteinuria (TP) (uAPR <0.4) and those with predominantly 'glomerular' proteinuria (GP) (uAPR ≥ 0.4).

RESULTS

A total of 618 of 5244 samples from 1378 patients had uPCR ≥ 30 mg/mmol. uAPRs were available in 144 patients: 46 patients (32%) had TP and 21 (15%) GP; the remainder had uPCR <30 mg/mmol. The TP group had a higher fractional excretion of phosphate compared with the GP group (mean 27% vs. 16%, respectively; P<0.01). Patients with TP were more likely to be on tenofovir and/or a boosted protease inhibitor compared with those with GP. In 18 patients with heavy proteinuria (uPCR >100 mg/mmol), a renal assessment was made; eight had a kidney biopsy. In all cases, the uAPR results correlated with the nephrological diagnosis.

CONCLUSIONS

In HIV-infected patients, measuring uAPR may help to identify patients in whom a renal biopsy is indicated, and those in whom tubular dysfunction might be an important cause of proteinuria and which may be related to antiretroviral toxicity. We suggest that this would be useful as a routine screening procedure in patients with proteinuria.

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.

Renal function declines more in tenofovir- than abacavir-based antiretroviral therapy in low-body weight treatment-naïve patients with HIV infection

Objective

To compare the rate of decline of renal function in tenofovir- and abacavir-based antiretroviral therapy (ART) in low-body weight treatment-naïve patients with HIV infection.

Design

We conducted a single-center retrospective cohort study of 503 Japanese patients who commenced on either tenofovir- or abacavir-based initial ART.

Methods

The incidence of renal dysfunction, defined as more than 25% fall in estimated glomerular filtration rate (eGFR) from the baseline, was determined in each group. The effect of tenofovir on renal dysfunction was estimated by univariate and multivariate Cox hazards models as the primary exposure. Changes in eGFR until 96 weeks were estimated in both groups with a repeated measures mixed model.

Results

The median body weight of the cohort was 64 kg. The estimated incidence of renal dysfunction in the tenofovir and the abacavir arm was 9.84 per 100 and 4.55 per 100 person-years, respectively. Tenofovir was significantly associated with renal dysfunction by univariate and multivariate analysis (HR = 1.747; 95% CI, 1.152–2.648; p = 0.009) (adjusted HR = 2.080; 95% CI, 1.339–3.232; p<0.001). In subgroup analysis of the patients stratified by intertertile baseline body weight, the effect of tenofovir on renal dysfunction was more evident in patients with lower baseline body weight by multivariate analysis (≤60 kg: adjusted HR = 2.771; 95%CI, 1.494–5.139; p = 0.001) (61–68 kg: adjusted HR = 1.908; 95%CI, 0.764–4.768; p = 0.167) (>68 kg: adjusted HR = 0.997; 95%CI, 0.318–3.121; p = 0.995). The fall in eGFR was significantly greater in the tenofovir arm than the abacavir arm after starting ART (p = 0.003).

Conclusion

The incidence of renal dysfunction in low body weight patients treated with tenofovir was twice as high as those treated with abacavir. Close monitoring of renal function is recommended for patients with small body weight especially those with baseline body weight <60 kg treated with tenofovir.

[Risk factors related to renal disorders in HIV-1 infected patients]

INTRODUCTION

Renal disease has emerged as one of the primary comorbid conditions affecting HIV-infected patients, mainly because antiretroviral therapy has improved survival. This study aimed to detect risk factors possibly associated with altered renal function in HIV-infected patients.

METHODS

A cross-sectional study was conducted involving 254 HIV-infected patients attending an outpatient clinic at Santa Casa de Vitoria< They were interviewed and blood samples were collected for CD4 cell counts, HIV-1 viral load, glucose, lipids and creatinine measurements. Urine protein was evaluated in the first voiding urine sample. Glomerular filtration was estimated by simplified modified diet in renal disease (MDRD) and Cockcroft-Gault formulas.

RESULTS

One hundred and three (40.6%) patients presented some urinary abnormality, and proteinuria was the most common finding (46; 18.1% patients). Twenty-five (9.8%) patients showed estimated glomerular filtration below 60 ml/min/1.73 m² by MDRD. Multivariate logistic regression showed that low glomerular filtration was positively correlated with black race [OR 9.6 (IC95% 1.28-23.80)], arterial hypertension [OR 3.3 (IC95% 1.28-23.81)], age over fifty-one years-old [OR 3.3 (IC95%1.11-9.90)], proteinuria [OR 5.2 {IC95% 1.67-16.25}]; hematuria [OR 3.2 (1.12-9.29)] and negatively correlated with patients using zidovudine [OR 0.2 (0.04-0.78)].

CONCLUSIONS

Traditional risk factors for renal disease, such as black race, arterial hypertension and advancing age were correlated with low estimated glomerular filtration in the present patient sample.

Impact of small body weight on tenofovir-associated renal dysfunction in HIV-infected patients: a retrospective cohort study of Japanese patients

Background

Treatment with tenofovir is sometimes associated with renal dysfunction. Limited information is available on this side effect in patients with small body weight, although the use of tenofovir will spread rapidly in Asia and Africa, where patients are likely to be of smaller body weight.

Methods

In a single-center cohort, Japanese patients with HIV infection who started tenofovir-containing antiretroviral therapy were retrospectively analyzed. The incidence of tenofovir-associated renal dysfunction, defined as more than 25% decrement of estimated glomerular filtration rate (eGFR) from the baseline, was determined. The effects of small body weight and body mass index (BMI) on tenofovir-associated renal dysfunction, respectively, were estimated in univariate and multivariate Cox hazards models as the primary exposure. Other possible risk factors were evaluated by univariate analysis and those found significant were entered into the multivariate analysis.

Results

The median weight of 495 patients was 63 kg. Tenofovir-related renal dysfunction occurred in 97 (19.6%) patients (incidence: 10.5 per 100 person-years). Univariate analysis showed that the incidence of tenofovir-related renal dysfunction was significantly associated with smaller body weight and BMI, respectively (per 5 kg decrement, HR = 1.23; 95% CI, 1.10–1.37; p<0.001)(per 1 kg/m² decrement, HR = 1.14; 95% CI, 1.05–1.23; p = 0.001). Old age, high baseline eGFR, low serum creatinine, low CD4 count, high HIV viral load, concurrent nephrotoxic drugs, hepatitis C infection, and current smoking were also associated with tenofovir-related renal dysfunction. Multivariate analysis identified small body weight as a significant risk (adjusted HR = 1.13; 95% CI, 1.01–1.27; p = 0.039), while small BMI had marginal significance (adjusted HR = 1.07; 95% CI 1.00–1.16; p = 0.058).

Conclusion

The incidence of tenofovir-associated renal dysfunction in Japanese patients was high. Small body weight was identified as an independent risk factor for tenofovir-associated renal dysfunction. Close monitoring of renal function is advocated for patients with small body weight treated with tenofovir.

[Protective role of antiretroviral treatment in the impairment of renal function in a cohort of human immunodeficiency virus patients]

BACKGROUND AND OBJECTIVE

To assess changes in renal function in a cohort of patients infected with the human immunodeficiency virus (HIV) and describe which factors are associated with deterioration.

PATIENTS AND METHODS

This was a prospective transversal study. The follow-up period was 12 months. Data were collected at baseline and one year including the glomerular filtration rate (GFR). We analyzed epidemiological data, comorbidities, CD4 lymphocytes, viral load, and AIDS status.

RESULTS

A total of 365 patients. Three hundred and thirteen (85%) were under highly active antiretroviral therapy (HAART); the median CD4 was 606 ± 314 and the CV was undetectable in 85%. At 1-year, we found a mean deterioration in the GFR of 9.7 ml/h. Eighty patients (21.8%) had a fall in GFR > 10 ml/h, while in 20 patients (5.8%) it was > 30 ml/h. An association was found regarding age, treatment with didanosine (DDI) and males (OR 1.89 95% CI 1.3 to 4.08, OR 2.3 95% CI 1.9 to 23 and OR 3.47 95% CI 1.6 to 14.20 respectively). We found a protective role of being under HAART (OR 0.54, 95% CI, 0.25 to 0.8).

CONCLUSIONS

There was a protective role of HAART in the deterioration of GFR of patients with HIV infection. Male gender, age and use of DDI were associated with worsening renal function. Tenofovir and protease inhibitors were not associated with further deterioration of renal function.

Managing the atazanavir-tacrolimus drug interaction in a renal transplant recipient

PURPOSE

The management of the drug interaction between atazanavir and tacrolimus in a renal transplant recipient is described.

SUMMARY

A 53-year-old African-American man with human immunodeficiency virus (HIV) received a renal transplant and was treated in accordance with a corticosteroid-sparing immunosuppressive protocol and maintenance immunosuppression with mycophenolate mofetil and tacrolimus. His highly active antiretroviral therapy included atazanavir 400 mg daily, abacavir 600 mg daily, and lamivudine 100 mg daily. Because of the potential for a significant interaction between tacrolimus and atazanavir, the tacrolimus dosage was to be based on serum tacrolimus concentrations. The patient was initially administered one dose of tacrolimus 0.5 mg on the morning of postoperative day 2. Evaluation of the tacrolimus profiles revealed that a higher dosage was necessary because serum tacrolimus levels decreased to subtherapeutic levels by 6 hours after dose administration. In an attempt to minimize tacrolimus toxicity and limit the duration of a subtherapeutic tacrolimus level, dosing was adjusted to 1 mg every 8 hours. After 48 hours of this regimen, peak serum tacrolimus levels were lower, and the drug concentrations remained at a relatively steady level throughout the dosing interval. One final dosage adjustment (1.5 mg every 12 hours) was performed to optimize serum tacrolimus levels and patient compliance.

CONCLUSION

In a 53-year-old man with HIV infection who underwent renal transplantation, the drug interaction between atazanavir and tacrolimus was managed by modifying the tacrolimus dosage regimen after determining the patient's blood tacrolimus concentration profile.

Secondary complications and co-infections in the HIV-infected adolescent in the antiretroviral era

PURPOSE OF REVIEW

The number of HIV-infected adolescents is increasing dramatically. With combination antiretroviral therapy, they are expected to live well into adulthood. However, complications are emerging at a higher rate in the HIV-infected population compared to the general population. HIV-infected adolescents are also at a high risk of sexually transmitted co-infections. This article reviews the main secondary complications and co-infections in the HIV-infected adolescent.

RECENT FINDINGS

HIV-infected adolescents are at a high risk of sexually transmitted infections. A careful, age-appropriate and developmentally appropriate inquiry into the individual's sexual behavior to assess risk is paramount, in addition to regular screening at medical visits. Treating co-infections is not only important for HIV-infected individuals, but also limits HIV transmission to others. In addition, monitoring and addressing modifiable secondary risk factors for complications such as renal disease, osteopenia or osteoporosis, and cardiovascular disease are critical, well before the onset of clinically apparent disease. Using antiretroviral therapy to suppress viral replication and inflammation appears to be a promising strategy for decreasing secondary complication risk, and likely overshadows the toxicities associated with the long-term use of certain antiretrovirals.

SUMMARY

Assessing and addressing the risk of secondary complications and co-infections in the HIV-infected adolescent is crucial for optimal length and quality of life.

Kidney tubular damage in the absence of glomerular defects in HIV-infected patients on highly active antiretroviral therapy

BACKGROUND

The emergence of kidney disease as an important comorbidity among human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) has emphasized the critical importance of early identification of patients at risk for kidney disease. Use of urine as a diagnostic medium may allow the noninvasive detection of incipient nephropathy in these patients.

METHODS

Here, we conducted cross-sectional and 1-year prospective studies of 424 HIV-infected patients on HAART without proteinuria or significant impairment of glomerular function. N-acetyl-β-D-glucosaminidase, γ-glutamyl transpeptidase, β(2)-microglobulin and α(1)-microglobulin were measured as indices of tubular damage, which was diagnosed when urinary concentrations of at least three tubular biomarkers exceeded the reference range. Risk factors associated with tubular damage were examined using multivariate logistic regression analysis.

RESULTS

Tubular damage was identified in 107 patients (25%), who were characterized by advanced age [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01-1.07], high C-reactive protein (OR, 1.96; 95% CI, 1.26-3.14) and coexisting diabetes mellitus (OR, 3.97; 95% CI, 1.44-12.2). The use of tenofovir, the most likely tubulotoxic agent, was not statistically involved in this subclinical tubular damage. The 1-year follow-up study showed that a decrease in estimated glomerular filtration rate (eGFR) and incidence of proteinuria during the period were significantly higher in patients with than without tubular damage.

CONCLUSIONS

A quarter of HIV-infected patients receiving HAART had subclinical tubular damage, which was associated with a near-term decline in eGFR and higher incidence of proteinuria. Periodic monitoring of urinary biomarkers might facilitate the early identification of HAART patients predisposed to significant kidney disease.

A simple model for predicting incidence of chronic kidney disease in HIV-infected patients

BACKGROUND

Human immunodeficiency virus (HIV)-infected individuals have concurrent risk factors for chronic kidney disease (CKD), but there are no prediction models to quantify the effect of multiple factors on the development of incident CKD.

METHODS

A 1-year prognostic model was developed using prospective data between January 2008 and March 2009, from a derivation cohort of 623 patients with an estimated glomerular filtration rate (eGFR) exceeding 60 ml/min/1.73 m(2) at baseline. Incident CKD was defined as both an eGFR falling below 60 ml/min/1.73 m(2) and a decrease in eGFR of at least 25% during the period. Continuous variables were divided into categories using the mean value of the whole cohort. Multivariate logistic regression was used to determine baseline categories associated with incident CKD. The model was tested with prospective data between April 2009 and March 2010, from a validation cohort of 534 patients exceeding 60 ml/min/1.73 m(2) at baseline, consisting of part of the derivation cohort and newly enrolled patients. The discriminative ability was evaluated using the area under the receiver operating characteristic (AROC) curve.

RESULTS

Eighteen subjects developed incident CKD (2.9%). In a multivariate logistic regression analysis of the derivation cohort, 5 variables (age, CD4 cell count, diabetes, proteinuria, and eGFR at baseline) were independently associated with the incidence of CKD. The AROC curve was 0.841 (95% CI 0.799-0.894) in the validation cohort.

CONCLUSION

This prediction model may be a useful tool for identifying HIV-infected individuals with a high likelihood of new-onset CKD.

Randomized comparison of renal effects, efficacy, and safety with once-daily abacavir/lamivudine versus tenofovir/emtricitabine, administered with efavirenz, in antiretroviral-naive, HIV-1-infected adults: 48-week results from the ASSERT study

BACKGROUND

Abacavir/lamivudine and tenofovir/emtricitabine fixed-dose combinations are commonly used first-line antiretroviral therapies, yet few studies have comprehensively compared their safety profiles.

METHODS

Forty-eight-week data are presented from this multicenter, randomized, open-label study comparing the safety profiles of abacavir/lamivudine and tenofovir/emtricitabine, both administered with efavirenz, in HLA-B*5701-negative HIV-1-infected adults.

RESULTS

Three hundred eighty-five subjects were enrolled in the study. The overall rate of withdrawal was high (28%). Changes in estimated glomerular filtration rate from baseline were similar between arms [difference 0.953 mL.min.1.73 m (95% confidence interval: -1.445 to 3.351), P = 0.435]. Urinary excretion of retinol-binding protein and beta-2 microglobulin increased significantly more in the tenofovir/emtricitabine arm (+50%; +24%) compared with the abacavir/lamivudine arm (no change; -47%) (P < 0.0001). A lower proportion achieved viral load <50 copies per milliliter in the abacavir/lamivudine arm (114 of 192, 59%) compared with the tenofovir/emtricitabine arm (137 of 193, 71%) [difference 11.6% (95% confidence interval: 2.2 to 21.1)]. The overall virological failure rate was low. The adverse event rate was similar between arms (except drug hypersensitivity, reported more in the abacavir/lamivudine arm).

CONCLUSIONS

The study showed no difference in estimated glomerular filtration rate between the arms, however, increases in markers of tubular dysfunction were observed in the tenofovir/emtricitabine arm, the long-term consequence of which is unclear. A significant difference in efficacy favoring tenofovir/emtricitabine was observed.

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.

Kidney function and the risk of cardiovascular events in HIV-1-infected patients

OBJECTIVE

Cardiovascular events (CVEs) are a significant cause of mortality in HIV/AIDS patients. The objective is to determine the correlation between kidney function and the risk of CVEs in the HIV-infected population.

DESIGN

Nested, matched, case-control study design was employed.

METHODS

: We performed a single-center study of 315 HIV-infected patients (63 patients who had CVEs and 252 controls). Estimated glomerular filtration rate (eGFR), calculated by the Chronic Kidney Disease Epidemiology Collaboration formula and the Modification of Diet in Renal Disease equation, and proteinuria were the primary exposures of interest.

RESULTS

Mean eGFR was significantly lower in the patients compared with controls (68.4 vs. 103.2 ml/min per 1.73 m, P < 0.001 by Chronic Kidney Disease Epidemiology Collaboration formula and 69.0 vs. 103.1 ml/min per 1.73 m, P < 0.001 by Modification of Diet in Renal Disease equation). In univariate analysis, an eGFR of less than 60 ml/min per 1.73 m was associated with a 15.9-fold increased odds of a CVE compared with an eGFR of at least 60 ml/min per 1.73 m (P < 0.001). In multivariate analysis, a 10 ml/min per 1.73 m decrease in eGFR was associated with a 20% increased odds of a CVE (odds ratio 1.2, 95% confidence interval 1.1-1.4). The prevalence of proteinuria in the patients was approximately twice that of controls (51 vs. 25%, P < 0.001). Proteinuria was associated with CVEs both in univariate and multivariate analyses (odds ratio 3.6, 95% confidence interval 1.9-7.0 and odds ratio 2.2, 95% confidence interval 1.1-4.8, respectively). Traditional cardiovascular risk factors, such as history of previous CVEs, diabetes mellitus, and dyslipidemia, along with low CD4 cell counts were also found as significant predictors of risk of CVEs.

CONCLUSION

Our study shows a significant independent association between decreased kidney function and increased risk of CVE in HIV-1-infected patients.

[Acute renal failure and hypercalcemia in an AIDS patient on tenofovir and low-dose vitamin D therapy with immune reconstitution inflammatory syndrome]

BACKGROUND

Tenofovir-containing antiviral therapy might result in acute renal failure and is able to induce tubular dysfunction with hypocalcemia. On the other hand, hypercalcemia induced by intoxication with colecalciferol has been described to induce renal failure in HIV-positive individuals as well. Here, the authors describe the unusual case of reversible renal failure due to hypercalcemia in a patient with low-dose colecalciferol substitution treated with tenofovir.

CASE REPORT

A 31-year-old HIV-positive female, CDC stage C3, was admitted to the authors' hospital with progressive renal failure and hypercalcemia. Antiretroviral therapy consisted of tenofovir and emtricitabine in combination with efavirenz. Additionally, she was on low-dose vitamin D(3) substitution (25 microg/d) and calcium supplementation (500 mg/d) due to systemic steroid treatment.

CONCLUSION

Additionally to regular control of renal function, serologic level of calcium should be supervised in patients concomitantly treated with tenofovir and colecalciferol.