Estimated glomerular filtration rate, chronic kidney disease and antiretroviral drug use in HIV-positive patients

High prevalence of signs of renal damage despite normal renal function in a cohort of HIV-infected patients: evaluation of associated factors

Renal disorders are an emerging problem in HIV-infected patients. We performed a cross-sectional study of the first 1000 HIV-infected patients attended at our HIV unit who agreed to participate. We determined the frequency of renal alterations and its related risk factors. Summary statistics and logistic regression were applied. The study sample comprised 970 patients with complete data. Most were white (94%) and men (76%). Median (IQR) age was 48 (42-53) years. Hypertension was diagnosed in 19%, dyslipidemia in 27%, and diabetes mellitus in 3%. According to the Chronic Kidney Disease Epidemiology Collaboration (CKD EPI) equation, 29 patients (3%) had an eGFR<60 ml/min/1.73 m(2); 18 of them (62%) presented altered albumin/creatinine and protein/creatinine (UPC or UAC) ratios. Of the patients with eGFR>60 mL/min, it was present in 293 (30%), 38 of whom (7.1%) had UPC>300 mg/g. Increased risk of renal abnormalities was correlated with hypertension (OR, 1.821 [95%CI, 1.292;2.564]; p=0.001), age (OR, 1.015 [95%CI, 1.001;1.030], per one year; p=0.040), and use of tenofovir disoproxil fumarate (TDF) plus protease inhibitor (PI), (OR, 1.401 [95%CI, 1.078;1.821]; p=0.012). Current CD4 cell count was a protective factor (OR, 0.9995 [95%CI, 0.9991;0.9999], per one cell; p=0.035). A considerable proportion of patients presented altered UPC or UAC ratios, despite having an eGFR>60 mL/min. CD4 cell count was a protective factor; age, hypertension, and use of TDF plus PIs were risk factors for renal abnormalities. Based on our results, screen of renal abnormalities should be considered in all HIV-infected patients to detect these alterations early.

Antiretroviral therapy: when to start

In this article, the scientific evidence and professional guidelines regarding the timing of antiretroviral therapy initiation are reviewed, with discussion of the increasingly persuasive evidence in favor of starting treatment early in the course of human immunodeficiency virus disease.

Changes in proteinuria and albuminuria with initiation of antiretroviral therapy: data from a randomized trial comparing tenofovir disoproxil fumarate/emtricitabine versus abacavir/lamivudine

BACKGROUND

Antiretroviral therapy (ART) is associated with improved kidney function; however, the nucleotide reverse transcriptase inhibitor (NRTI) tenofovir disoproxil fumarate (TDF) has been associated with decreased kidney function and proteinuria.

METHODS

We examined changes in urine protein:creatinine (UPCR) and urine albumin:creatinine (UACR) ratios in 245 ART-naive participants in A5202 randomized in a substudy to blinded NRTI (abacavir/lamivudine, ABC/3TC, n = 124 or TDF/emtricitabine, TDF/FTC, n = 121) with open-label protease inhibitor (PI) atazanavir/ritonavir or nonnucleoside reverse transcriptase inhibitor (NNRTI) efavirenz.

RESULTS

At baseline, 18% of participants had clinically significant proteinuria (UPCR ≥200 mg/g), and 11% had clinically significant albuminuria (UACR ≥30 mg/g). The prevalence of clinically significant proteinuria and albuminuria decreased from baseline to week 96 in all treatment groups. In intention-to-treat analyses, there was a significant effect of NRTI component on fold change in UPCR (P = 0.011) and UACR (P = 0.018) from baseline to week 96, with greater improvements in participants randomized to ABC/3TC. There was no significant effect of NNRTI/PI component on fold change in UPCR (P = 0.23) or UACR (P = 0.88), and no significant interactions between NRTI and NNRTI/PI components.

CONCLUSIONS

In this prespecified secondary analysis, ART initiation was associated with improvements in proteinuria and albuminuria, with significantly greater improvements in participants randomized to ABC/3TC versus TDF/FTC. These are the first data from a randomized trial to suggest that initiation of TDF/FTC may not be associated with the same degree of improvement in proteinuria and albuminuria that have been reported with other regimens. Future studies should consider the long-term clinical significance of these findings.

Long-term exposure to tenofovir continuously decrease renal function in HIV-1-infected patients with low body weight: results from 10 years of follow-up

OBJECTIVES

To investigate the effect of long-term tenofovir disoproxil fumarate (TDF) use on renal function, especially in patients with low body weight who are vulnerable to TDF nephrotoxicity.

DESIGN

A single-center, observational study in Tokyo, Japan.

METHODS

We performed a 10 years cohort study of 792 HIV-1-infected patients. The effect of long-term TDF use on estimated glomerular filtration rate (eGFR) was investigated on treatment-naive patients who started TDF-containing antiretroviral therapy (n = 422) and those who started abacavir-containing antiretroviral therapy as control (n = 370). Three renal endpoints were examined by the logistic regression model: decrement in eGFR of higher than 10 ml/min per 1.73 m relative to the baseline, more than 25% decrement in eGFR, and eGFR lower than 60 ml/min per 1.73 m at least 3 months apart. The loss in eGFR was estimated using linear mixed models for repeated measures.

RESULTS

The median weight at baseline was 63 kg. TDF use increased the risk of all three renal outcomes compared with the control group: higher than 10 ml/min per 1.73 m decrement in eGFR [adjusted odds ratio (OR) = 2.1, 95% confidence interval (CI) 1.45-3.14, P < 0.001], more than 25% decrement (adjusted OR = 2.1, 95% CI 1.50-2.90, P < 0.001), and eGFR lower than 60 ml/min per 1.73 m at least 3 months apart (adjusted OR = 3.9, 95% CI 1.62-9.36, P = 0.002). The cumulative mean loss relative to the control after 1, 2, 3, 4, and 5 years of TDF exposure was -3.8, -3.6, -5.5, -6.6, and -10.3 ml/min per 1.73 m, respectively, indicating that the loss in eGFR increased over time (P < 0.001).

CONCLUSION

In this cohort of patients with low body weight, TDF exposure increased the risk of renal dysfunction. Furthermore, the loss in eGFR relative to the control increased continuously up to 5 years.

Comparison of renal changes with lopinavir/ritonavir plus raltegravir or tenofovir/emtricitabine in the PROGRESS study

ABSTRACT 

Aim: To assess renal function changes among 172 treatment-naive subjects treated with lopinavir/ritonavir (LPV/r) plus raltegravir (RAL) or LPV/r plus tenofovir/emtricitabine in the PROGRESS study, a prospective, randomized controlled trial. Patients & methods: Serum creatinine, creatinine clearance and chronic kidney disease category were compared between groups. Results: Mean change from baseline to week 96 in creatinine clearance was smaller with LPV/r plus RAL versus LPV/r plus tenofovir/emtricitabine (-1.4 vs -7.3 ml/min; p = 0.035). Chronic kidney disease category improvement was more frequent and the mean increase in serum creatinine was smaller for the LPV/r plus RAL group. Differences in estimated renal function were also detected when the analysis was performed according to baseline demographics. Conclusion: Smaller renal function declines were observed with LPV/r plus RAL. The results from this study warrant further evaluation of the renal safety profile of nucleotide reverse transcriptase inhibitor-sparing regimens.

Low-grade proteinuria is highly prevalent in HIV-positive patients on antiretroviral treatment

OBJECTIVES

HIV-positive patients are at an increased risk for chronic kidney disease. However, these data mainly derive from cohorts with a high percentage of African-American patients, representing a specific ethnical risk group for chronic kidney disease. The aim of this study was to estimate the prevalence and risk factors specifically for early signs of kidney dysfunction in a large, predominantly white cohort of HIV patients.

DESIGN

Cross-sectional study.

METHODS

Prevalence of low-grade proteinuria was measured by quantitative analysis of urinary protein-to-creatinine ratio (cutoff >70 mg/g) and further differentiated by assessing α1-microglobulin (tubular proteinuria) and albumin-to-creatinine ratio (glomerular proteinuria) of HIV patients attending the University Hospital in Cologne, Germany. Together with standard and HIV-related laboratory findings and medical history, risk factors for each form of proteinuria were identified using multivariate forward selection.

RESULTS

Of 945 enrolled patients, 55% were identified with low-grade proteinuria, 41% with tubular proteinuria, and 20% with glomerular proteinuria. Older age was a risk factor for all forms of proteinuria in multivariate analysis. Low-grade proteinuria was also associated with concomitant diabetes and exposure to nucleoside reverse transcriptase inhibitor [anytime during HIV infection, not tenofovir (TDF)-specific], whereas tubular proteinuria was linked to current and any exposure to nucleoside reverse transcriptase inhibitor (TDF-specific). Further risk factors for glomerular proteinuria were hypertension and diabetes in this cohort.

CONCLUSION

Low-grade, glomerular and tubular proteinuria are highly prevalent in this large white HIV cohort. Older age represents a nonmodifiable risk factor for all forms of proteinuria. Glomerular proteinuria is associated with modifiable cardiovascular, but not HIV-related risk factors, whereas tubular proteinuria is linked to TDF exposure.

Rosuvastatin preserves renal function and lowers cystatin C in HIV-infected subjects on antiretroviral therapy: the SATURN-HIV trial

BACKGROUND

In chronic human immunodeficiency virus (HIV) infection, plasma cystatin C may be influenced by factors other than glomerular filtration rate such as inflammation. Statins may improve cystatin C by improving glomerular function or by decreasing inflammation.

METHODS

The Stopping Atherosclerosis and Treating Unhealthy Bone With Rosuvastatin in HIV (SATURN-HIV) trial randomized 147 patients on stable antiretroviral therapy (ART) with low-density lipoprotein cholesterol ≤130 mg/dL to blinded 10 mg daily rosuvastatin or placebo. We analyzed relationships of baseline and 0- to 24-week changes in plasma cystatin C concentration with measures of vascular disease, inflammation, and immune activation.

RESULTS

Median age was 46 (interquartile range, 40-53) years; 78% were male, 68% African American. Tenofovir and protease inhibitors were used in 88% and 49% of subjects, respectively. Baseline cystatin C was associated with higher carotid intima-media thickness and epicardial adipose tissue independent of age, sex, and race. Biomarkers of endothelial activation and inflammation were associated with cystatin C in a multivariable model independent of creatinine-based estimated glomerular filtration rate (eGFRcr). After 24 weeks, statin use slowed mean eGFRcr decline (1.61 vs -3.08 mL/minute/1.73 m(2) for statin vs placebo; P = .033) and decreased mean cystatin C (-0.034 mg/L vs 0.010 mg/L; P = .008). Within the statin group, changes in cystatin C correlated with changes in endothelial activation, inflammation, and T-cell activation.

CONCLUSIONS

Rosuvastatin 10 mg daily reduces plasma cystatin C and slows kidney function decline in HIV-infected patients on ART. Reductions in cystatin C with statin therapy correlate with reductions in inflammatory biomarkers. Relationships between cystatin C, kidney function, and cardiovascular risk in HIV may be mediated in part by inflammation. Clinical Trials Registration. NCT01218802.

Antiretroviral therapy, immune suppression and renal impairment in HIV-positive persons

PURPOSE OF REVIEW

The purpose of this article is to review recent literature on antiretroviral treatment (ART) and immune suppression as risk factors for renal impairment in HIV-positive persons, and to discuss pending research questions within this field.

RECENT FINDINGS

Several individual antiretroviral agents (ARVs) including tenofovir and several protease inhibitors have, in diverse study settings, been associated with renal impairment. Traditional renal risk factors are common among those experiencing adverse renal impairment to ARVs, but do not fully explain why only some develop these effects. Discontinuation of nephrotoxic ARVs is common with declining renal function, but has unknown long-term consequences. Immune suppression is a strong independent risk factor for renal impairment, and ongoing investigations will clarify whether initiating ARVs with nephrotoxic properties at higher CD4 cell counts will have net beneficial effects on renal function.

SUMMARY

With improvements in survival, multiple risk factors have emerged for renal impairment in HIV-positive persons. Although certain ARVs may cause moderate renal impairment, effects on more severe renal impairment remain unresolved. Regular renal function monitoring allow for switching away from nephrotoxic ARVs in case of decreasing function. If such actions prove beneficial higher prevalence of ARV-associated severe renal impairment may emerge in populations without access to regular monitoring.

Tenofovir-induced nephrotoxicity: incidence, mechanism, risk factors, prognosis and proposed agents for prevention

OBJECTIVE

In this study, data regarding epidemiology, risk factors, pathogenesis and outcome of tenofovir-induced nephrotoxicity will be reviewed, and current and future approaches for prevention will be discussed.

METHOD

The data were collected by searching Scopus, PubMed, Medline, Science direct, Clinical trials and Cochrane database systematic reviews. The keywords used as search terms were "Tenofovir", "TDF", "NRTI", "Nephrotoxicity", "Renal failure", "Kidney damage", "HIV" and "AIDS".

RESULTS AND CONCLUSION

Several predisposing factors including elevated baseline SCr, concomitant nephrotoxic medications, low body weight, advanced age, tenofovir disoproxil fumarate (TDF) dose and duration of treatment and lower CD4 cell count were identified as risk factors for development of TDF-induced nephrotoxicity. Cellular accumulation through increased entry from the human organic anion transporters and decreased efflux into tubular lumen is main mechanism of nucleotide analogue antiviral induced nephrotoxicity. Renal function assessment and monitoring at baseline and during TDF treatment are the main approach of prevention of TDF-induced nephrotoxicity. Rosiglitazone may be helpful in patients presenting with TDF-induced nephrotoxicity. Pretreatment with melatonin prevented all known histological changes in proximal tubular mitochondira induced by TDF. Use of antioxidants with mitochondria-targeted properties such as MitoQ or Mito-CP may prevent proximal tubular mitochondrial against TDF damage. Vitamin E, ebselen, lipoic acid, plastoquinone, nitroxides, SOD enzyme mimetics, Szeto-Schiller (SS) peptides, and quercetin are other potential agents for prevention of TDF-induced nephrotoxicity. However, data regarding effectiveness of nephroprotective agents against TDF-induced nephrotoxicity are not conclusive. Before extrapolation of the preclinical evidence to clinical practice, these evidence should be confirmed in future human studies.

Advances in the pathogenesis of HIV-associated kidney diseases

Despite improved outcomes among persons living with HIV who are treated with antiretroviral therapy, they remain at increased risk for acute and chronic kidney diseases. Moreover, since HIV can infect renal epithelial cells, the kidney might serve as a viral reservoir that would need to be eradicated when attempting to achieve full virologic cure. In recent years, much progress has been made in elucidating the mechanism by which HIV infects renal epithelial cells and the viral and host factors that promote development of kidney disease. Polymorphisms in APOL1 confer markedly increased risk of HIV-associated nephropathy; however, the mechanism by which ApoL1 variants may promote kidney disease remains unclear. HIV-positive persons are at increased risk of acute kidney injury, which may be a result of a high burden of subclinical kidney disease and/or viral factors and frequent exposure to nephrotoxins. Despite the beneficial effect of antiretroviral therapy in preventing and treating HIVAN, and possibly other forms of kidney disease in persons living with HIV, some of these medications, including tenofovir, indinavir, and atazanavir can induce acute and/or chronic kidney injury via mitochondrial toxicity or intratubular crystallization. Further research is needed to better understand factors that contribute to acute and chronic kidney injury in HIV-positive patients and to develop more effective strategies to prevent and treat kidney disease in this vulnerable population.

Cystatin C-based renal function changes after antiretroviral initiation: a substudy of a randomized trial

BACKGROUND

The effects of antiretrovirals on cystatin C-based renal function estimates are unknown.

METHODS

We analyzed changes in renal function using creatinine and cystatin C-based estimating equations in 269 patients in A5224s, a substudy of study A5202, in which treatment-naive patients were randomized to abacavir/lamivudine or tenofovir/emtricitabine with open-label atazanavir/ritonavir or efavirenz.

RESULTS

Changes in renal function significantly improved (or declined less) with abacavir/lamivudine treatment compared with tenofovir/emtricitabine using the Cockcroft-Gault formula (P = .016) and 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI; P = .030) and 2012 CKD-EPI cystatin C-creatinine (P = .025). Renal function changes significantly improved (or declined less) with efavirenz compared with atazanavir/ritonavir (P < .001 for all equations). Mean (95% confidence interval) renal function changes specifically for tenofovir/emtricitabine combined with atazanavir/ritonavir were -8.3 (-14.0, -2.6) mL/min with Cockcroft-Gault; -14.9 (-19.7, -10.1) mL/min per 1.73(2) with Modification of Diet in Renal Disease; -12.8 (-16.5, -9.0) mL/min per 1.73(2) with 2009 CKD-EPI; +8.9 (4.2, 13.7) mL/min per 1.73(2) with 2012 CKD-EPI cystatin C; and -1.2 (-5.1, 2.6) mL/min per 1.73(2) with 2012 CKD-EPI cystatin C-creatinine. Renal function changes for the other treatment arms were more favorable but similarly varied by estimating equation.

CONCLUSIONS

Antiretroviral-associated changes in renal function vary in magnitude and direction based on the estimating equation used.

Screening for decreased glomerular filtration rate and associated risk factors in a cohort of HIV-infected patients in a middle-income country

With the introduction of combined active antiretroviral therapy and the improved survival of HIV-infected patients, degenerative diseases and drug toxicity have emerged as long-term concerns. We studied the prevalence of decreased glomerular filtration rate (GFR) and associated risk factors in a cohort of HIV-infected patients from a middle-income country. Our cross-sectional study included all adult patients who attended an urban outpatient clinic in 2008. GFR was estimated using the CKD-EPI equation. The prevalence ratio (PR) of decreased GFR (defined as <60 mL/min/1.73 m²) was estimated using generalizing linear models assuming a Poisson distribution. We analyzed data from 1,970 patients, of which 82.9% had been exposed to ART. A total of 249 patients (12.6%) had a GFR between 60 and 89 mL/min/1.73 m², 3.1% had a GFR between 30 and 59, 0.3% had a GFR between 15 and 29, and 0.4% had a GFR <15. Decreased GFR was found in only 74 patients (3.8%). In the multivariate regression model, the factors that were independently associated with a GFR below 60 mL/min/1.73 m² were as follows: age ≥50 years (PR = 3.4; 95% CI: 1.7–6.8), diabetes (PR = 2.0; 95% CI: 1.2–3.4), hypertension (PR = 2.0; 95% CI: 1.3–3.2), current CD4+ cell count <350 cells/mm3 (PR = 2.1; 95% CI: 1.3–3.3), past exposure to tenofovir (PR = 4.7; 95% CI: 2.3–9.4) and past exposure to indinavir (PR = 1.7; 95% CI: 1.0–2.8). As in high-income countries, CKD was the predominant form of kidney involvement among HIV-infected individuals in our setting. The risk factors associated with decreased glomerular filtration were broad and included virus-related factors as well as degenerative and nephrotoxic factors. Despite the potential for nephrotoxicity associated with some antiretroviral drugs, in the short-term, advanced chronic renal disease remains very rare.

Urine liver-type fatty acid-binding protein and kidney injury molecule-1 in HIV-infected patients receiving combined antiretroviral treatment based on tenofovir

The aim of this study was to determine the presence of kidney tubular damage in the absence of overt evidence of glomerular dysfunction (GFR>60 ml/min without proteinuria) in HIV-infected patients receiving antiretroviral therapy. Urine kidney injury molecule-1 (KIM-1) and liver-type fatty acid-binding protein (L-FABP) levels were measured by ELISA and expressed as a ratio to creatinine. Sixty-six patients (median age 38 years) and 10 healthy controls (median age 35.5 years) were included in the study. Patients with chronic diseases such as diabetes, hypertension, heart disease, or kidney disease were excluded from the study. All patients received tenofovir/emtricitabine combined with one of three other components, namely efavirenz, atazanavir/norvir, or lopinavir/norvir. A lower concentration of L-FABP/creatinine was observed in HIV-infected as compared to healthy individuals (p=0.0353); KIM-1/creatinine was also lower in comparison with healthy controls but not statistically significantly. Patients receiving efavirenz had higher levels of L-FABP/creatinine in comparison to healthy controls (p=0.0039). Patients with anti-HCV had higher concentrations of L-FABP/creatinine as compared to the HIV-monoinfected individuals (not statistically significant) and to healthy subjects (p=0.0356). All four patients with L-FABP>17.5 μg/g creatinine were HIV/HCV coinfected. On multivariate logistic regression urine L-FABP above 5.5 μg/g creatinine was independently associated with body weight (OR=0.93 p=0.039). This study suggests that HIV/HCV-coinfected patients with lower body weight treated with tenofovir may be at an increased risk of tubular dysfunction and should be monitored more closely. The use of protease inhibitors was not associated with an increased risk of tubular disorders.

Impaired Urine Dilution Capability in HIV Stable Patients

Renal disease is a well-recognized complication among patients with HIV infection. Viral infection itself and the use of some antiretroviral drugs contribute to this condition. The thick ascending limb of Henle's loop (TALH) is the tubule segment where free water clearance is generated, determining along with glomerular filtration rate the kidney's ability to dilute urine. Objective. We analyzed the function of the proximal tubule and TALH in patients with HIV infection receiving or not tenofovir-containing antiretroviral treatment in comparison with healthy seronegative controls, by applying a tubular physiological test, hyposaline infusion test (Chaimowitz' test). Material & Methods. Chaimowitz' test was performed on 20 HIV positive volunteers who had normal renal functional parameters. The control group included 10 healthy volunteers. Results. After the test, both HIV groups had a significant reduction of serum sodium and osmolarity compared with the control group. Free water clearance was lower and urine osmolarity was higher in both HIV+ groups. Proximal tubular function was normal in both studied groups. Conclusion. The present study documented that proximal tubule sodium reabsorption was preserved while free water clearance and maximal urine dilution capability were reduced in stable HIV patients treated or not with tenofovir.

Development of a definition for Rapid Progression (RP) of renal function in HIV-positive persons: the D:A:D study

Background

No consensus exists on how to define abnormally rapid deterioration in renal function (Rapid Progression, RP). We developed an operational definition of RP in HIV-positive persons with baseline estimated glomerular filtration rate (eGFR) >90 ml/min/1.73 m² (using Cockcroft Gault) in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study from 2004 to 2011.

Methods

Two definitions were evaluated; RP definition A: An average eGFR decline (slope) ≥5 ml/min/1.73 m²/year over four years of follow-up with ≥3 eGFR measurements/year, last eGFR <90 ml/min/1.73 m² and an absolute decline ≥5 ml/min/1.73 m²/year in two consecutive years. RP definition B: An absolute annual decline ≥5 ml/min/1.73 m²/year in each year and last eGFR <90 ml/min/1.73 m². Sensitivity analyses were performed considering two and three years’ follow-up. The percentage with and without RP who went on to subsequently develop incident chronic kidney disease (CKD; 2 consecutive eGFRs <60 ml/min/1.73 m² and 3 months apart) was calculated.

Results

22,603 individuals had baseline eGFR ≥90 ml/min/1.73 m². 108/3655 (3.0%) individuals with ≥4 years’ follow-up and ≥3 measurements/year experienced RP under definition A; similar proportions were observed when considering follow-up periods of three (n=195/6375; 3.1%) and two years (n=355/10756; 3.3%). In contrast under RP definition B, greater proportions experienced RP when considering two years (n=476/10756; 4.4%) instead of three (n=48/6375; 0.8%) or four (n=15/3655; 0.4%) years’ follow-up. For RP definition A, 13 (12%) individuals who experienced RP progressed to CKD, and only (21) 0.6% of those without RP progressed to CKD (sensitivity 38.2% and specificity 97.4%); whereas for RP definition B, fewer RP individuals progressed to CKD.

Conclusions

Our results suggest using three years’ follow-up and at least two eGFR measurements per year is most appropriate for a RP definition, as it allows inclusion of a reasonable number of individuals and is associated with the known risk factors. The definition does not necessarily identify all those that progress to incident CKD, however, it can be used alongside other renal measurements to early identify and assess those at risk of developing CKD. Future analyses will use this definition to identify other risk factors for RP, including the role of antiretrovirals.

Predictors of HIV-associated nephropathy

Renal disease accounts for significant morbidity and mortality in patients with HIV-1 infection. HIV-associated nephropathy (HIVAN) is an important cause of end stage renal disease in this population. Although multiple genetic, clinical, and laboratory characteristics such as Apolipoproetin-1 genetic polymorphism, high viral load, low CD-4 count, nephrotic range proteinuria, and increased renal echogenicity on ultrasound are predictive of HIVAN, kidney biopsy remains the gold standard to make the definitive diagnosis. Current treatment options for HIVAN include initiation of combined active antiretroviral therapy, blockade of the renin-angiotensin system, and steroids. In patients with progression of HIVAN, renal transplant should be pursued as long as their systemic HIV infection is controlled.

Deteriorating renal function and clinical outcomes in HIV-positive persons

OBJECTIVES

To determine the relationship between measures of renal function [current estimated glomerular filtration rate (eGFR) and proportion of follow-up with a low eGFR (%FU ≤60 ml/min)] and fatal/ nonfatal AIDS, non-AIDS events and all-cause mortality.

DESIGN

An observational, longitudinal cohort study of 12 155 persons from EuroSIDA.

METHODS

Persons with at least one eGFR measurement after 1 January 2004, using the CKD-EPI formula, were included. Poisson regression analyses were used to determine whether current eGFR or %FU of 60 ml/min or less were independent prognostic markers for clinical events.

RESULTS

During 61 425 person-years of follow-up (PYFU), the crude incidence of deaths was 11.1/1000 PYFU [95% confidence interval (CI) 10.0-12.1] at current eGFR more than 90 ml/min and 199.6 (95% CI 1144.3-254.3/1000 PYFU) when current eGFR was 30 ml/min or less. Corresponding figures for AIDS were 12.2 (11.1-13.3) and 63.9 (36.5-103.7) and for non-AIDS were 16.0 (14.8-17.3) and 203.6 (147.7-259.5). After adjustment, current eGFR of 30 ml/min or less was a strong predictor of death [adjusted incidence rate ratios (aIRR) 4.35; 95% CI 3.20-5.91] and non-AIDS events (3.63; 95% CI 2.57-5.13), although the relationship with AIDS was less strong (1.45; 95% CI 1.01-2.08). After adjustment, %FU of 60 ml/min or less was associated with a 22% increased incidence of death (aIRR 1.22 per 10% longer; 95% CI 1.18-1.27), a 13% increased incidence of non-AIDS events (95% CI 1.08-1.18) and a 15% increased incidence of AIDS events (95% CI 1.06-1.24).

CONCLUSION

Both current eGFR and %FU of 60 ml/min or less were associated with death and non-AIDS events in HIV-positive persons. Our findings highlight the association between underlying renal dysfunction and morbidity and mortality in HIV infection, although reverse causality cannot be excluded.

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.

Incomplete reversibility of estimated glomerular filtration rate decline following tenofovir disoproxil fumarate exposure

Background. Tenofovir disoproxil fumarate (TDF) has been linked to renal impairment, but the extent to which this impairment is reversible is unclear. We aimed to investigate the reversibility of renal decline during TDF therapy.

Methods. Cox proportional hazards models assessed factors associated with discontinuing TDF in those with an exposure duration of >6 months. In those who discontinued TDF therapy, linear piecewise regression models estimated glomerular filtration rate (eGFR) slopes before initiation of, during, and after discontinuation of TDF therapy. Factors associated with not achieving eGFR recovery 6 months after discontinuing TDF were assessed using multivariable logistic regression.

Results. We observed declines in the eGFR during TDF exposure (mean slopes, −15.7 mL/minute/1.73 m²/year [95% confidence interval {CI}, −20.5 to −10.9] during the first 3 months and −3.1 mL/minute/1.73 m²/year [95% CI, −4.6 to −1.7] thereafter) and evidence of eGFR increases following discontinuation of TDF therapy (mean slopes, 12.5 mL/minute/1.73 m²/year [95% CI, 8.9–16.1] during the first 3 months and 0.8 mL/minute/1.73 m²/year [95% CI, .1–1.5] thereafter). Following TDF discontinuation, 38.6% of patients with a decline in the eGFR did not experience recovery. A higher eGFR at baseline, a lower eGFR after discontinuation of TDF therapy, and more-prolonged exposure to TDF were associated with an increased risk of incomplete recovery 6 months after discontinuation of TDF therapy.

Conclusions. This study shows that a decline in the eGFR during TDF therapy was not fully reversible in one third of patients and suggests that prolonged TDF exposure at a low eGFR should be avoided.

Effect of baseline renal function on tenofovir-containing antiretroviral therapy outcomes in Zambia

BACKGROUND

Although tenofovir disoproxil fumarate (TDF) use has increased as part of first-line antiretroviral therapy (ART) across sub-Saharan Africa, renal outcomes among patients receiving TDF remain poorly understood. We assessed changes in renal function and mortality in patients starting TDF- or non-TDF-containing ART in Lusaka, Zambia.

METHODS

We included patients aged ≥16 years who started ART from 2007 onward, with documented baseline weight and serum creatinine. Renal dysfunction was categorized as mild (estimated glomerular filtration rate [eGFR], 60-89 mL/min), moderate (30-59 mL/min), or severe (<30 mL/min) according to the chronic kidney disease-epidemiology (CKD-EPI) formula. Differences in eGFR during ART were analyzed using linear mixed-effect models. The odds of developing moderate or severe eGFR decrease and mortality were assessed using logistic and competing risk regression, respectively.

RESULTS

We included 62 230 adults, of which 38 716 (62.2%) initiated a TDF-based regimen. The proportion with moderate or severe renal dysfunction at baseline was lower in the TDF than in the non-TDF group (1.9% vs 4.0%). Among patients with no or mild renal dysfunction, those receiving TDF were more likely to develop moderate (adjusted odds ratio, 3.11; 95% confidence interval, 2.52-3.87) or severe (2.43; 1.80-3.28) eGFR decrease, although the incidence in such episodes was low. Among patients with moderate or severe renal dysfunction at baseline, renal function improved independently of ART regimen, and mortality rates were similar in both treatment groups.

CONCLUSIONS

TDF use did not attenuate renal function recovery or increase the mortality rate in patients with renal dysfunction. Further studies are needed to determine the role of routine renal function monitoring before and during ART use in Africa.

The changing epidemiology of HIV-related chronic kidney disease in the era of antiretroviral therapy

The epidemiology of kidney disease in HIV-infected individuals has changed significantly since the introduction of combination antiretroviral therapy (cART) in the mid 1990s. HIV-associated nephropathy (HIVAN), an aggressive form of collapsing focal segmental glomerulosclerosis (FSGS) caused by direct HIV infection of the kidney in a genetically susceptible host, emerged early in the HIV epidemic as a leading cause of end-stage renal disease. With the widespread use of cART, HIVAN is increasingly rare in populations with access to care, and the spectrum of HIV-related chronic kidney disease now reflects the growing burden of comorbid disease in the aging HIV population. Nonetheless, available data suggest that both HIV infection and cART nephrotoxicity continue to contribute to the increased risk of chronic kidney disease in HIV-infected individuals in the United States and Europe. Despite the genetic susceptibility to HIVAN in individuals of West African descent, limited data are available to define the prevalence and spectrum of HIV-related kidney disease in sub-Saharan Africa, which is home to two-thirds of the world's HIV population. In this mini-review, we characterize the changing epidemiology of HIV-related chronic kidney disease in Western nations and in sub-Saharan Africa.

Factors affecting glomerular filtration rate, as measured by iohexol disappearance, in men with or at risk for HIV infection

OBJECTIVE

Formulae used to estimate glomerular filtration rate (GFR) underestimate higher GFRs and have not been well-studied in HIV-infected (HIV(+)) people; we evaluated the relationships of HIV infection and known or potential risk factors for kidney disease with directly measured GFR and the presence of chronic kidney disease (CKD).

DESIGN

Cross-sectional measurement of iohexol-based GFR (iGFR) in HIV(+) men (n = 455) receiving antiretroviral therapy, and HIV-uninfected (HIV(-)) men (n = 258) in the Multicenter AIDS Cohort Study.

METHODS

iGFR was calculated from disappearance of infused iohexol from plasma. Determinants of GFR and the presence of CKD were compared using iGFR and GFR estimated by the CKD-Epi equation (eGFR).

RESULTS

Median iGFR was higher among HIV(+) than HIV(-) men (109 vs. 106 ml/min/1.73 m(2), respectively, p = .046), and was 7 ml/min higher than median eGFR. Mean iGFR was lower in men who were older, had chronic hepatitis C virus (HCV) infection, or had a history of AIDS. Low iGFR (≤90 ml/min/1.73 m(2)) was associated with these factors and with black race. Other than age, factors associated with low iGFR were not observed with low eGFR. CKD was more common in HIV(+) than HIV(-) men; predictors of CKD were similar using iGFR and eGFR.

CONCLUSIONS

iGFR was higher than eGFR in this population of HIV-infected and -uninfected men who have sex with men. Presence of CKD was predicted equally well by iGFR and eGFR, but associations of chronic HCV infection and history of clinically-defined AIDS with mildly decreased GFR were seen only with iGFR.

Predictors of advanced chronic kidney disease and end-stage renal disease in HIV-positive persons

OBJECTIVES

Whilst several antiretroviral drugs have been associated with moderate chronic kidney disease (CKD), their contribution to advanced CKD and end-stage renal disease (ESRD) remain unknown.

DESIGN

D:A:D participants with at least three estimated glomerular filtration rates (eGFR) after February 2004 were followed until the first of advanced CKD (confirmed eGFR ≤ 30 ml/min, ≥3 months apart), ESRD (dialysis ≥3 months/ transplantation), 6 months after last visit or February 2012.

METHODS

Poisson regression was used to assess risk factors for advanced CKD/ESRD including exposure to potential nephrotoxic antiretroviral drugs and antiretroviral drug discontinuation rates according to latest eGFR.

RESULTS

Among 35 192 persons contributing 200 119 person years of follow-up (PYFU), 135 (0.4%) developed advanced CKD (n = 114)/ESRD (n = 21); incidence rate = 0.67 [95% confidence interval (CI), 0.56-0.79]/1000 PYFU. Tenofovir (TDF) was particularly frequently discontinued as eGFR declined. After adjustment, those previously exposed but currently off TDF had similar advanced CKD/ESRD rate ratios compared with those unexposed [1.00 (95% CI, 0.66-1.51)], while those currently on TDF had reduced rates [0.23 (95% CI, 0.13-0.41)]. No consistent associations with other antiretroviral drugs were seen. Results were robust after time-lagging antiretroviral drug exposure, stratifying by baseline eGFR, and allowing for competing risks. Other predictors were diabetes, hypertension, baseline eGFR, smoking and current CD4 cell count. The incidence rate in nonsmokers with baseline eGFR > 60 and no diabetes or hypertension was 0.16 (95% CI 0.09-0.26)/1000 PYFU.

CONCLUSION

Neither current nor recent antiretroviral drug use predicted advanced CKD/ESRD during 6 years median follow-up in a large, heterogenenous and primarily white cohort. TDF discontinuation rates increased with decreasing eGFR, leaving a selected group still on TDF at lower advanced CKD/ESRD risk. Traditional renal risk factors and current CD4 cell count were the strongest advanced CKD/ESRD predictors.

Screening and management of renal disease in human immunodeficiency virus-infected patients in Australia

BACKGROUND

Renal disease has become one of the most important comorbidities observed in the human immunodeficiency virus (HIV)-infected patient cohort. Data are lacking on the current screening and management of renal disease in patients with HIV. We evaluated HIV-infected Australian adults in primary care to determine current practices.

METHODS

This prospective, multicentre observational study included two rounds of data collection; the first was followed by an educational programme. Outcomes included screening for renal disease; management of risk factors for kidney disease and other comorbidities associated with renal disease.

RESULTS

Fifty-three general practitioners participated with 733 patients enrolled. Most were male (94%); almost 40% were 41-50 years of age, and 6% and 84% were receiving antiretroviral therapy. Comorbidities were common; 19% had hypertension, 5% were diabetic, 32% were dyslipidaemic, and 40% were smokers. Estimated glomerular filtration rate was commonly measured in both rounds of data collection (96% vs 95%). Proteinuria was assessed less frequently; this improved after education (48% vs 71%). Almost 10% of patients tested had proteinuria on urinalysis. Of the 45 patients (6%) with renal impairment (estimated glomerular filtration rate <60 mL/min), none was referred for assessment by a renal specialist.

CONCLUSIONS

This large observational study provides important information on renal disease in HIV-infected patients, an area with a paucity of clinical data. Current screening and management practices fall short of suggested guidelines. Failure to refer patients to specialists is a major deficiency. Improvements with education suggest the need to promote awareness of guidelines in primary care doctors.

The validity of the modification of diet in renal disease formula in HIV-infected patients: a systematic review

RATIONALE, AIMS AND OBJECTIVES

Renal dysfunction is highly prevalent in HIV-infected patients and may require dose adjustment of renally excreted antiretroviral drugs. The Modification of Diet in Renal Disease (MDRD)-4 formula is frequently used in daily practice to estimate patients' renal function. The aim of this systematic review was to assess the validity of the MDRD-4 formula in HIV-infected patients.

METHOD

A systematic search in Pubmed and EMBASE was done to identify studies which compared MDRD-4 with measured glomerular filtration rate (mGFR) in HIV-infected patients.

RESULTS

Five studies were included, which provided data from 464 HIV-infected patients with mean mGFR ranging from 87 to 118 ml/min/1.73 m(2). In all studies, results from the MDRD-4 gave an underestimation of the mGFR. Mean bias ((MDRD-4) - mGFR) ranged from -6 to -11 ml/min/1.73 m(2) across studies. The accuracy expressed in terms of P 30 ranged from 64 to 89 %.

CONCLUSIONS

The MDRD-4 formula is as valid in HIV-positive as in HIV-negative patients. Because the available studies comprised mainly HIV-infected patients with mildly impaired to good renal function (GFR ≥ 60 ml/min/1.73 m(2)), more research is needed to validate the MDRD-4 formula in HIV-infected patients with moderate to severe renal impairment.

Antiretroviral regimens sparing agents from the nucleoside(tide) reverse transcriptase inhibitor class: a review of the recent literature

The nucleoside(tide) reverse transcriptase inhibitors (NRTIs) have traditionally been an important 'back-bone' of an antiretroviral therapy (ART) regimen. However all agents have been associated with both short- and long-term toxicity. There have also been concerns regarding the efficacy and safety of a treatment sequencing strategy in which those with past exposure and/or resistance to one or more NRTIs are re-exposed to 'recycled' NRTIs in subsequent ART regimens. Newer, potent and possible safer, agents from various ART classes continue to become available. There has therefore been growing interest in evaluating NRTI-sparing regimens. In this review, we examined studies of NRTI-sparing regimens in adult HIV-positive patients with varying degrees of ART experience. We found that in treatment experienced patients currently on a failing regimen with detectable viral load, there now exists a robust evidence for the use of NRTI-sparing regimens including raltegravir with a boosted-protease inhibitor with or without a third agent. In those on a virologically suppressive regimen switching to a NRTI-sparing regimen or in those ART-naïve patients initiating an NRTI-sparing regimen, evidence is sparse and largely comes from small exploratory trials or observational studies. Overall, these studies suggest that caution needs to be exercised in carefully selecting the right candidate and agents, especially in the context of a dual-therapy regimen, to minimise the risks of virological failure. There is residual toxicity conferred by the ritonavir boost in protease-inhibitor containing NRTI-sparing regimens. Fully-powered studies are needed to explore the place of N (t)RTI-sparing regimens in the sequencing of ART. Additionally research is required to explore how to minimise the adverse effects associated with ritonavir-based pharmacoenhancement.

WHO antiretroviral therapy guidelines 2010 and impact of tenofovir on chronic kidney disease in Vietnamese HIV-infected patients

Objective

The 2010 WHO antiretroviral therapy (ART) guidelines have resulted in increased tenofovir use. Little is known about tenofovir-induced chronic kidney disease (CKD) in HIV-infected Vietnamese with mean body weight of 55 kg. We evaluated the prevalence and risk factors of CKD in this country.

Design

Cross-sectional study was performed.

Methods

Clinical data on HIV-infected Vietnamese cohort were collected twice a year. To evaluate the prevalence of CKD, serum creatinine was measured in 771 patients in October 2011 and April 2012. CKD was defined as creatinine clearance less than 60 ml/min at both time points. Multivariate logistic regression was used to determine the factors associated with CKD

Results

Tenofovir use increased in Vietnam from 11.9% in April 2011 to 40.3% in April 2012. CKD was diagnosed in 7.3%, of which 7% was considered moderate and 0.3% was severe. Multivariate analysis of October-2011 data identified age per year-increase (OR: 1.229, 95%CI, 1.170-1.291), body weight per 1 kg-decrement (1.286, 1.193-1.386), and tenofovir use (2.715, 1.028-7.168) as risk factors for CKD.

Conclusions

Older age, low body weight and tenofovir use were independent risk factors for CKD in Vietnam. Further longitudinal study is required to evaluate the impact of TDF on renal function in Vietnam and other countries with small-body weight patients.

[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America.

RESULTS

cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis.

CONCLUSIONS

These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.

Ritonavir-boosted darunavir is rarely associated with nephrolithiasis compared with ritonavir-boosted atazanavir in HIV-infected patients

Background

Although ritonavir-boosted atazanavir (ATV/r) is known to be associated with nephrolithiasis, little is known about the incidence of nephrolithiasis in patients treated with ritonavir-boosted Darunavir (DRV/r), the other preferred protease inhibitor.

Methods

In a single-center cohort, the incidence of nephrolithiasis was compared between HIV-infected patients who commenced DRV/r-containing antiretroviral therapy and those on ATV/r. The effects of ATV/r use over DRV/r were estimated by univariate and multivariate Cox hazards models.

Results

Renal stones were diagnosed in only one patient (0.86 per 1000 person-years) of the DRV/r group (n=540) and 37 (20.2 per 1000 person-years) of the ATV/r group (n=517). The median [interquartile (IQR)] observation period in the DRV/r group was 27.1 months (IQR 18.1-38.4 months), and 40.6 months (IQR 17.5-42.7) for the ATV/r group. The total observation period was 1,163.6 person-years and 1,829.6 person-years for the DRV/r group and for the ATV/r group, respectively. In the 37 patients on ATV/r who developed nephrolithiasis, the median time from commencement of ATV/r to diagnosis was 28.1 months (IQR 18.4–42.7), whereas nephrolithiasis in the single patient of the DRV/r group occurred 11.2 month after the introduction of DRV/r. ATV/r use over DRV/r was significantly associated with nephrolithiasis by uni- and multivariate analyses (HR=26.01; 95% CI, 3.541–191.0; p=0.001) (adjusted HR=21.47; 95% CI, 2.879–160.2; p=0.003).

Conclusion

The incidence of nephrolithiasis was substantially lower in patients on DRV/r than those on ATV/r. The results suggest that DRV/r should be selected for treatment of HIV-infected patients at risk of chronic kidney disease.

A comparison of estimated glomerular filtration rates using Cockcroft-Gault and the Chronic Kidney Disease Epidemiology Collaboration estimating equations in HIV infection

OBJECTIVES

The aim of this study was to determine whether the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)- or Cockcroft-Gault (CG)-based estimated glomerular filtration rates (eGFRs) performs better in the cohort setting for predicting moderate/advanced chronic kidney disease (CKD) or end-stage renal disease (ESRD).

METHODS

A total of 9521 persons in the EuroSIDA study contributed 133 873 eGFRs. Poisson regression was used to model the incidence of moderate and advanced CKD (confirmed eGFR < 60 and < 30 mL/min/1.73 m(2) , respectively) or ESRD (fatal/nonfatal) using CG and CKD-EPI eGFRs.

RESULTS

Of 133 873 eGFR values, the ratio of CG to CKD-EPI was ≥ 1.1 in 22 092 (16.5%) and the difference between them (CG minus CKD-EPI) was ≥ 10 mL/min/1.73 m(2) in 20 867 (15.6%). Differences between CKD-EPI and CG were much greater when CG was not standardized for body surface area (BSA). A total of 403 persons developed moderate CKD using CG [incidence 8.9/1000 person-years of follow-up (PYFU); 95% confidence interval (CI) 8.0-9.8] and 364 using CKD-EPI (incidence 7.3/1000 PYFU; 95% CI 6.5-8.0). CG-derived eGFRs were equal to CKD-EPI-derived eGFRs at predicting ESRD (n = 36) and death (n = 565), as measured by the Akaike information criterion. CG-based moderate and advanced CKDs were associated with ESRD [adjusted incidence rate ratio (aIRR) 7.17; 95% CI 2.65-19.36 and aIRR 23.46; 95% CI 8.54-64.48, respectively], as were CKD-EPI-based moderate and advanced CKDs (aIRR 12.41; 95% CI 4.74-32.51 and aIRR 12.44; 95% CI 4.83-32.03, respectively).

CONCLUSIONS

Differences between eGFRs using CG adjusted for BSA or CKD-EPI were modest. In the absence of a gold standard, the two formulae predicted clinical outcomes with equal precision and can be used to estimate GFR in HIV-positive persons.

Antiretroviral therapy-induced changes in plasma lipids and the risk of kidney dysfunction in HIV-infected men

In the context of HIV, the initiation of effective antiretroviral therapy (ART) has been found to increase the risk of dyslipidemia in HIV-infected individuals, and dyslipidemia has been found to be a risk factor for kidney disease in the general population. Therefore, we examined changes in lipid profiles in HIV-infected men following ART initiation and the association with future kidney dysfunction. HIV-infected men from the Multicenter AIDS Cohort Study initiating ART between December 31, 1995 and September 30, 2011 with measured lipid and serum creatinine values pre-ART and post-ART were selected. The associations between changes in total cholesterol or high-density lipoprotein following ART initiation and the estimated change in glomerular filtration rate (eGFR) over time were assessed using piecewise linear mixed effects models. There were 365 HIV-infected men who contributed to the analysis. In the adjusted models, at 3 years post-ART, those with changes in total cholesterol >50 mg/dl had an average decrease in eGFR of 2.6 ml/min/1.73 m(2) per year (p<0.001) and at 5 years post-ART, the average decrease was 2.4 ml/min/1.73 m(2) per year (p=0.008). This decline contrasted with the estimates for those with changes in total cholesterol ≤ 50 mg/dl: 1.4 ml/min/1.73 m(2) decrease per year (p<0.001) and 0.1 ml/min/1.73 m(2) decrease per year (p=0.594) for the same time periods, respectively. Large decreases in high-density lipoprotein (a decline of greater than 5 mg/dl) were not associated with declines in eGFR. These results indicate that large ART-related increases in total cholesterol may be a risk factor for kidney function decline in HIV-infected men. Should these results be generalizable to the broader HIV population, monitoring cholesterol changes following the initiation of ART may be important in identifying HIV-infected persons at risk for kidney disease.

A review of cardiovascular and renal function monitoring: a consideration of older adults with HIV

The prevalence of human immunodeficiency virus (HIV) infection in older and elderly adults is significant worldwide. This population poses new challenges and opportunities in the management of HIV. In addition to the risks affecting HIV patients of all ages, including risk of opportunistic infection and medication resistance, age-related changes in physiology, higher comorbidity burdens, increased use of medications, and potential adverse drug reactions to HIV medications all factor into the care of older adults with HIV. The risk and progression of cardiovascular and renal comorbidities may be higher in the older adult HIV population and in patients taking specific HIV medications. Understanding these risks is essential when managing a new type of patient: the older adult with HIV.

Comparisons of creatinine and cystatin C for detection of kidney disease and prediction of all-cause mortality in HIV-infected women

BACKGROUND

Cystatin C could improve chronic kidney disease (CKD) classification in HIV-infected women relative to serum creatinine.

DESIGN

Retrospective cohort analysis.

METHODS

Cystatin C and creatinine were measured from specimens taken and stored during the 1999-2000 examination among 908 HIV-infected participants in the Women's Interagency HIV study (WIHS). Mean follow-up was 10.2 years. Predictors of differential glomerular filtration rate (GFR) estimates were evaluated with multivariable linear regression. The associations of baseline categories (<60, 60-90, and >90 ml/min per 1.73 m) of creatinine estimated GFR (eGFRcr), cystatin C eGFR (eGFRcys), and combined creatinine-cystatin C eGFR (eGFRcr-cys) with all-cause mortality were evaluated using multivariable Cox regression. The net reclassification index (NRI) was calculated to evaluate the effect of cystatin C on reclassification of CKD staging.

RESULTS

CKD risk factors were associated with lower eGFRcys and eGFRcr-cys values compared with eGFRcr. Relative to eGFR more than 90, the eGFR less than 60 category by eGFRcys (Adjusted hazard ratio: 2.56; 95% confidence interval: 1.63-4.02), eGFRcr-cys (3.11; 1.94-5.00), and eGFRcr (2.34; 1.44-3.79) was associated with increased mortality risk. However, the eGFR 60-90 category was associated with increased mortality risk for eGFRcys (1.80; 1.28-2.53) and eGFRcr-cys (1.91; 1.38-2.66) but not eGFRcr (1.20; 0.85-1.67). The overall NRI for mortality was 26% when reclassifying from eGFRcr to eGFRcys (P < 0.001) and was 20% when reclassifying from eGFRcr to eGFRcr-cys (P < 0.001).

CONCLUSION

The addition of cystatin C may improve mortality risk prediction by stages of kidney function relative to creatinine. CKD risk factors are associated with an overestimate of GFR by serum creatinine relative to cystatin C.

Acute kidney injury caused by tenofovir disoproxil fumarate and diclofenac co-administration

OBJECTIVES

The renal elimination of tenofovir (TFV) may be subject to renal drug-drug interactions that may increase the risk of kidney injury. Case reports indicated that diclofenac might increase TFV-associated nephrotoxicity via a drug-drug interaction, leading to an increased intracellular TFV concentration in proximal tubular cells.

METHODS

A retrospective analysis of data for all patients from the Frankfurt HIV Cohort (FHC) who had diclofenac prescriptions between January 2008 and June 2012 was carried out.

RESULTS

Among 89 patients with diclofenac use, 61 patients (68.5%) were treated with tenofovir disoproxil fumarate (TDF) and 28 patients (31.5%) were treated with TDF-sparing combination antiretroviral therapy (cART). Thirteen patients (14.6%) developed acute kidney injury (AKI) shortly after initiating diclofenac treatment. AKI occurred exclusively in TDF-treated patients, although all had previously stable renal function. All cases were accompanied by new onset of at least two parameters indicating proximal tubular damage, such as normoglycaemic-glucosuria and hypophosphataemia. TFV-associated nephrotoxicity was demonstrated by renal biopsy in four cases. Additionally, 11.5% of patients on TDF treatment developed new-onset proximal tubular damage, while having a preserved glomerular filtration rate. In contrast, diclofenac did not affect renal function in patients with TDF-sparing cART, as only one case of isolated hypophataemia was observed in these patients. In univariate analysis, risk factors for AKI were TDF-containing cART (P = 0.0076) and pre-existing hypophosphataemia (P = 0.0086).

CONCLUSIONS

Drug-drug interaction caused by diclofenac could exacerbate TFV-associated nephrotoxicity. Diclofenac should be used with caution in patients on TDF therapy, especially in those with hypophosphataemia. Our findings need to be confirmed in larger studies.

Increased risk of dialysis and end-stage renal disease among HIV patients in Denmark compared with the background population

BACKGROUND

HIV patients have increased risk of impaired renal function. We aimed to estimate the incidence of any renal replacement therapy (aRRT) and start of chronic renal replacement therapy (cRRT) among HIV patients compared with population controls.

METHODS

In a nationwide, population-based cohort study we analysed incidence rates (IR), incidence rate ratios (IRR) and risk factors for aRRT and cRRT among HIV patients compared with an age- and gender-matched population control cohort using Poisson regression.

RESULTS

We identified 5300 HIV patients and 53 000 population controls. The IRs per 10 000 person-years of aRRT and cRRT among HIV patients were 15.9 (95% CI: 12.5-20.1) and 4.4 (95% CI: 2.8-6.9), respectively. The IRR was 4.7 (95% CI: 3.5-6.2) for aRRT and 3.6 (95% CI: 2.2-6.0) for cRRT compared with population controls. Risk of aRRT was increased during the first year after HIV diagnosis [IRR 3.5 (95% CI: 1.5-8.1)], after a diagnosis of AIDS [IRR 2.3 (95% CI: 1.3-3.9)], in intravenous drug users [IRR 6.0 (95% CI: 2.9-12.2)] and in patients with hypertension [IRR 7.0 (95% CI: 3.7-13.2)]. Factors associated with increased risk of cRRT were hypertension [IRR 20 (95% CI: 6.8-61)] and baseline eGFR < 60 mL/min pr. 1.73 m(2) [IRR 7.8 (95% CI: 1.2-50)]. Exposure to tenofovir and/or atazanavir was not associated with risk of aRRT or cRRT.

CONCLUSIONS

The risk of aRRT is increased more than 4-fold and the risk of cRRT is increased more than 3-fold in HIV patients in Denmark compared with the background population. We found no association between exposure to tenofovir, atazanavir or the combination of the two and risk of aRRT or cRRT.

Estimating kidney function in HIV-infected adults in Kenya: comparison to a direct measure of glomerular filtration rate by iohexol clearance

Background

More than two-thirds of the world's HIV-positive individuals live in sub-Saharan Africa, where genetic susceptibility to kidney disease is high and resources for kidney disease screening and antiretroviral therapy (ART) toxicity monitoring are limited. Equations to estimate glomerular filtration rate (GFR) from serum creatinine were derived in Western populations and may be less accurate in this population.

Methods

We compared results from published GFR estimating equations with a direct measure of GFR by iohexol clearance in 99 HIV-infected, ART-naïve Kenyan adults. Iohexol concentration was measured from dried blood spots on filter paper. The bias ratio (mean of the ratio of estimated to measured GFR) and accuracy (percentage of estimates within 30% of the measured GFR) were calculated.

Results

The median age was 35 years, and 60% were women. The majority had asymptomatic HIV, with median CD4+ cell count of 355 cells/mm³. Median measured GFR was 115 mL/min/1.73 m². Overall accuracy was highest for the Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation. Consistent with a prior report, bias and accuracy were improved by eliminating the coefficient for black race (85% of estimates within 30% of measured GFR). Accuracy of all equations was poor in participants with GFR 60–90 mL/min/1.73 m² (<65% of estimates within 30% of measured GFR), although this subgroup was too small to reach definitive conclusions.

Conclusions

Overall accuracy was highest for the CKD-EPI equation. Eliminating the coefficient for race further improved performance. Future studies are needed to determine the most accurate GFR estimate for use in individuals with GFR <90 mL/min/1.73 m², in whom accurate estimation of kidney function is important to guide drug dosing. Direct measurement of GFR by iohexol clearance using a filter paper based assay is feasible for research purposes in resource-limited settings, and could be used to develop more accurate GFR estimates in African populations.

Impact of a tenofovir disoproxil fumarate plus ritonavir-boosted protease inhibitor-based regimen on renal function in HIV-infected individuals: a prospective, multicenter study

BACKGROUND

The aim of this study was to investigate the impact of a tenofovir disoproxil fumarate (TDF) plus ritonavir-boosted protease inhibitor (PI/r) regimen on renal function in Chinese HIV-infected patients.

METHODS

Seventy-five HIV-1 infected patients failing first-line antiretroviral therapy (ART) comprised the TDF+PI/r group. Seventy-five HIV-1 infected patients matched for gender, age, and renal function made up the control. All subjects completed follow-up visits over 48 weeks. CD4 cell count, plasma HIV-1 viral load, and urine protein level were assessed at the trial start (baseline, week 0) and at week 48. The serum creatinine and estimated glomerular filtration rate (eGFR) were monitored at each follow-up point. Change in eGFR from baseline to week 48 was also compared.

RESULTS

Compared to control, the TDF+PI/r group exhibited higher levels of serum creatinine (79 vs. 69.7 μmol/L, P<0.001) and a lower rate of eGFR (93.0 vs. 101.6 ml/min/1.73 m², P=0.009) at the end of week 48. Patients treated with TDF+PI/r showed greater decline in eGFR than control (-8.8 vs. 6.4 ml/min/1.73 m², P<0.001). Compared to baseline renal function of the control group, the TDF+PI/r group exhibited a greater median decline in eGFR at the end of week 48 (P<0.001).

CONCLUSIONS

We found that a TDF+PI/r based ART regimen resulted in greater renal function decline over 48 weeks. Therefore, renal function should be monitored especially when TDF is used in combination with PI/r.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00872417.

Role of traditional risk factors and antiretroviral drugs in the incidence of chronic kidney disease, ANRS CO3 Aquitaine cohort, France, 2004-2012

Objective

To examine the role of antiretroviral drugs (ART), HIV-related and traditional risk factors on the incidence of chronic kidney disease (CKD) in HIV-infected patients.

Design

Prospective hospital-based cohort of HIV-infected patients from 2004 to 2012.

Methods

CKD was defined using MDRD equation as an estimated glomerular filtration rate (eGFR) less than 60 ml/mn/1.73 m² at 2 consecutive measurements ≥3 months apart. Poisson regression models were used to study determinants of CKD either measured at baseline or updated. ART exposure was classified as ever or never. We additionally tested the role of tenofovir (TDF), whether or not prescribed concomitantly with a Protease Inhibitor (PI), taking into account the cumulative exposure to the drug.

Results

4,350 patients (74% men) with baseline eGFR>60 ml/mn/1.73 m² were followed for a median of 5.8 years. At the end of follow-up, 96% had received ART, one third of them (35%) jointly received TDF and a PI. Average incidence rate of CKD was 0.95% person-years of follow-up. Incidence of CKD was higher among women (IRR = 2.2), older patients (>60 y vs <45 y: IRR = 2.5 and 45–60 y: IRR = 1.7), those with diabetes (IRR = 1.9), high blood pressure (IRR = 1.5), hyperlipidemia (IRR = 1.5), AIDS stage (IRR = 1.4), low baseline eGFR (IRR = 15.8 for 60<eGFR<70 ml/mn/1.73 m² vs >90 and IRR = 7.1 for 70<eGFR<80 ml/mn/1.73 m²), current CD4+<200 cells/mm³ vs >500/mm³ (IRR = 2.5), and exposure to TDF (IRR = 2.0). Exposure to TDF was even strongly associated with CKD when co-administered with PIs (IRR = 3.1 vs 1.3 when not, p<0,001). A higher risk of CKD was found when tenofovir exposure was >12 months [IRR = 3.0 with joint PIs vs 1.3 without (p<0.001)]. A vast majority of those developing CKD (76.6%) had a baseline eGFR between 60 and 80 ml/mn/1.73 m².

Conclusion

In patients with eGFR between 60 and 80 mL/min/1.73 m², a thorough control of CKD risk factors is warranted. The use of TDF, especially when co-administered with PIs, should be mentioned as a relative contraindication in presence of at least one of these risk factors.

The significance of antiretroviral-associated acute kidney injury in a cohort of ambulatory human immunodeficiency virus-infected patients

BACKGROUND

To determine the incidence and significance of acute kidney injury (AKI) after initiating highly active antiretroviral therapy (HAART).

METHODS

A prospective cohort study of 271 consecutively treated HIV-infected patients, initiating first (75) or sequential HAART (196) from January 2008 to June 2011. AKI was diagnosed according to the Risk, Injury, Failure, Loss of kidney function, End-stage renal disease (RIFLE)/Acute Kidney Injury Network (AKIN) criteria, and the risk of progression to chronic kidney disease (CKD) was evaluated.

RESULTS

A greater estimated glomerular filtration rate (eGFR) decrease after 1 year was observed for patients initiating a tenofovir disoproxil fumarate (TDF)-based regimen (-6.45 versus +0.98 mL/min/1.73 m(2) when compared with patients without TDF; P < 0.01), both in the case of the first (-8.5 versus -2.27; P = 0.04) or successive regimens (-5.3 versus + 1.18 mL/min/1.73 m(2); P < 0.01). AKI, as defined, was observed in 10% (28 cases, 6.98 episodes/100 patients-year), mostly stage I (27 cases), in a median time of 6 (3-16.5) months. Four cases (14%), having a worse baseline renal function progressed to CKD, whereas four recovered completely. In the multivariate analysis, AKI was associated with the concomitant use of cotrimoxazole prophylaxis and to low CD4+ count. CKD was diagnosed in 2% (six cases) of patients. Therefore, the overall rate of HAART-associated renal disorders was 11% (30 cases, 7.46 episodes/100 patients-year (95% confidence interval, 6.09-8.83).

CONCLUSIONS

The initiation of a tenofovir-based regimen is followed by a significant decline in eGFR, although it could be misinterpreted by the concomitant use of cotrimoxazole. A substantial proportion of patients develop AKI, but only a minority progress to CKD. Patients initiating HAART and developing AKI should be carefully monitored for progression of renal disease.

Prevalence of renal disease within an urban HIV-infected cohort in northern Italy

BACKGROUND

Renal disease is an increasingly recognized noninfectious comorbidity associated with human immunodeficiency virus (HIV) infection.

METHODS

Our retrospective, cross-sectional study evaluated prevalence of nephropathy among HIV-infected patients followed up in our outpatient clinic during the year 2011. Renal dysfunction and chronic kidney disease (CKD) were defined as estimated glomerular filtration rate (eGFR) <90 ml/min per 1.73 m(2) and as renal damage or eGFR <60 ml/min per 1.73 m(2) over a 3-month or greater period, respectively.

RESULTS

We enrolled 894 HIV-infected patients with a mean age of 44.2 years and a mean current CD4 lymphocyte count of 508 cells/mm(3). The prevalence of renal dysfunction and CKD was 27.4 and 21.3 %, respectively. Older age, male gender, hypertension, diabetes, proteinuria, hypertriglyceridemia, lower nadir CD4 cell count, current use of tenofovir or tenofovir plus a ritonavir-boosted protease inhibitor were independently associated with renal dysfunction.

CONCLUSION

Renal dysfunction is a frequent comorbidity among HIV-infected persons and requires a careful clinical and laboratory monitoring of renal function.

Tubular and glomerular proteinuria in HIV-infected adults with estimated glomerular filtration rate ≥ 60 ml/min per 1.73 m2

OBJECTIVE

To assess the frequency of glomerular and tubular proteinuria in a cohort of HIV-infected patients, and to determine the factors associated with each type of injury.

DESIGN

Cross-sectional study of 1210 consecutive HIV-infected adults followed in HIV outpatient unit (Montpellier/France).

METHODS

Spot urine protein to creatinine (uPCR), albumin to creatinine (uACR) and albumin to protein (uAPR) ratios were assessed. Glomerular injury was defined as uACR at least 30 mg/g or uPCR at least 200 mg/g with uAPR at least 0.4. Tubular injury was defined as uPCR 200 mg/g or more with uAPR less than 0.4. Multivariate logistic regression identified independent factors of each type of proteinuria, in the 1158 patients with estimated glomerular filtration rate (eGFR) at least 60 ml/min per 1.73 m, using re-expressed modification of diet in renal disease equation.

RESULTS

Frequency of proteinuria was 18.2% among patients with eGFR at least 60 ml/min per 1.73 m consisting in tubular proteinuria for 50.7% of them. Factors associated with glomerular proteinuria were age [OR 1.34/10-year increment (95%CI: 1.08-1.66)], diabetes [OR 3.37 (95%CI: 1.53-7.44)], and arterial hypertension [OR 2.52 (95%CI: 1.36-4.66)]. Factors associated with tubular proteinuria were age [OR 1.43 (95%CI: 1.14-1.79)], current tenofovir use [OR 3.52 (95%CI: 1.86-6.65)], hepatitis C co-infection [OR 1.62 (95%CI: 1.00-2.65)], AIDS stage [OR 1.83 (95%CI: 1.18-2.82)], CD4 cell count less than 200 per μl [OR 2.48 (95%CI: 1.31-4.70)].

CONCLUSION

This study distinguished risk factors for tubular injury, mainly related to HIV disease and its treatment (tenofovir), and glomerular injury, linked to non HIV-related variables (age, diabetes, hypertension). Measuring uPCR, uACR and uAPR may help with the detection and specific management of early chronic kidney disease in HIV-infected patients having normal or sub-normal eGFR.

Antiretroviral-treated HIV-infected women have similar long-term kidney function trajectories as HIV-uninfected women

Natural history studies suggest increased risk for kidney function decline with HIV infection, but few studies have made comparisons with HIV-uninfected women. We examined whether HIV infection treated with highly active antiretroviral therapy (HAART) remains associated with faster kidney function decline in the Women's Interagency HIV Study. HIV-infected women initiating HAART with (n=105) or without (n=373) tenofovir (TDF) were matched to HIV-uninfected women on calendar and length of follow-up, age, systolic blood pressure, hepatitis C antibody serostatus, and diabetes history. Linear mixed models were used to evaluate differences in annual estimated glomerular filtration rate (eGFR). Person-visits were 4,741 and 11,512 for the TDF-treated and non-TDF-treated analyses, respectively. Mean baseline eGFRs were higher among women initiated on TDF-containing HAART and lower among those on TDF-sparing HAART compared to their respective HIV-uninfected matches (p<0.05 for both). HIV-infected women had annual rates of eGFR changes similar to HIV-uninfected matches (p-interaction >0.05 for both). Adjusting for baseline eGFR, mean eGFRs at 1 and 3 years of follow-up among women initiated on TDF-containing HAART were lower than their uninfected matches (-4.98 and -4.26 ml/min/1.73 m(2), respectively; p<0.05 for both). Mean eGFR of women initiated on TDF-sparing HAART was lower versus uninfected matches at 5 years (-2.19 ml/min/1.73 m(2), p=0.03). HAART-treated HIV-infected women had lower mean eGFRs at follow-up but experienced rates of annual eGFR decline similar to HIV-uninfected women. Tenofovir use in HIV-infected women with normal kidney function did not accelerate long-term kidney function decline relative to HIV-uninfected women.

Proteinuria in paediatric patients with human immunodeficiency virus infection

In human immunodeficiency virus (HIV)-infected people kidney disease is as an important cause of morbidity and mortality. Clinical features of kidney damage in HIV-infected patients range from asymptomatic microalbuminuria to nephrotic syndrome. The lack of specific clinical features despite the presence of heavy proteinuria may mask the renal involvement. Indeed, it is important in HIV patients to monitor renal function to early discover a possible kidney injury. After the introduction of antiretroviral therapy, mortality and morbidity associated to HIV-infection have shown a substantial reduction, although a variety of side effects for long-term use of highly active antiretroviral therapy, including renal toxicity, has emerged. Among more than 20 currently available antiretroviral agents, many of them can occasionally cause reversible or irreversible nephrotoxicity. At now, three antiretroviral agents, i.e., indinavir, atazanavir and tenofovir disoproxil fumarate have a well established association with direct nephrotoxicity. This review focuses on major causes of proteinuria and other pathological findings related to kidney disease in HIV-infected children and adolescents.

Advanced chronic kidney disease, end-stage renal disease and renal death among HIV-positive individuals in Europe

OBJECTIVES

Knowledge about advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) in HIV-positive persons is limited. The aim of this study was to investigate incidence, predictors and outcomes for advanced CKD/ESRD and renal death.

METHODS

Advanced CKD was defined as confirmed (two consecutive measurements ≥ 3 months apart) estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m(2) using Cockcroft-Gault, and ESRD as haemodialysis or peritoneal dialysis for ≥ 1 month or renal transplant. Renal death was death with renal disease as the underlying cause, using Coding Causes of Death in HIV (CoDe) methodology. Follow-up was from 1 January 2004 until last eGFR measurement, advanced CKD, ESRD or renal death, whichever occurred first. Poisson regression was used to identify predictors.

RESULTS

Of 9044 individuals included in the study, 58 (0.64%) experienced advanced CKD/ESRD/renal death [incidence rate 1.32/1000 person-years of follow-up (PYFU); 95% confidence interval (CI) 0.98-1.66]; 52% of those who experienced the endpoint had a baseline eGFR ≤ 60 mL/min/1.73 m(2) compared with 3% of those who did not. Using Kaplan-Meier methods, at 6 years from baseline, 0.83% (95% CI 0.59-1.07%) were estimated to have experienced the endpoint overall and 11.26% (95% CI 6.75-15.78%) among those with baseline eGFR ≤ 60 mL/min/1.73 m(2) . Independent predictors of the endpoint included any cardiovascular event [incidence rate ratio (IRR) 2.16; 95% CI 1.24-3.77], lower eGFR (IRR 0.64 per 5 mL/min/1.73 m(2) ; 95% CI 0.59-0.70) and lower CD4 count (IRR 0.77 per doubling; 95% CI 0.62-0.95). One year after experiencing advanced CKD or ESRD, an estimated 19.21% (95% CI 7.84-30.58%) of patients had died, mostly from extra-renal causes.

CONCLUSIONS

The incidence of advanced CKD/ESRD/renal death was low and predictors included traditional renal risk factors, HIV-related factors and pre-existing renal impairment. The prognosis following advanced CKD/ESRD was poor. Larger studies should address possible contributions of specific antiretrovirals.