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

Severe lactic acidosis during tenofovir disoproxil fumarate and cobicistat combination for HIV patient

Lactic acidosis is a rare but serious side effect in individuals receiving nucleoside reverse transcriptase inhibitors. An underweight woman with HIV was admitted to our hospital because of nausea and diffuse myalgia. Her antiretroviral regimen had been changed to tenofovir disoproxil fumarate (TDF)/emtricitabine and darunavir/cobicistat 3 months prior, after which her renal function had gradually declined. After admission, she was diagnosed with lactic acidosis, and a liver biopsy suggested mitochondrial damage. Her plasma tenofovir levels were elevated at the onset of lactic acidosis. We hypothesise that the patient's low body weight, combined with the addition of cobicistat, induced renal dysfunction and led to elevated plasma tenofovir concentrations, resulting in mitochondrial damage and lactic acidosis. Careful monitoring of renal function and lactic acidosis is required during use of TDF-containing regimens for underweight HIV patients, particularly when combined with cobicistat.

Incidence of impaired kidney function among people with HIV: a systematic review and meta-analysis

Background

In the era of combination antiretroviral therapy (ART), the incidence, manifestations and severity of kidney diseases have dramatically changed in people living with HIV (PLWH). Little is known about the incidence of impaired kidney function (IKF) measured by serum creatine-based estimated glomerular filtration rate (eGFR) in PLWH.

Methods

In this systematic review and meta-analysis, we searched PubMed, Ovid, Medline, Embase and Web of Science for studies published before May 7th, 2021, with estimates of incidence of IKF among PLWH. We independently reviewed each study for quality by using the Newcastle-Ottawa scale. The incidence and 95% confidence intervals (CIs) were calculated using random-effects model.

Results

Sixty out of 3797 identifiable studies were eligible for the meta-analysis. A total of 19 definitions of IKF were described and categorized into three types: the threshold of eGFR, an absolute or percent decrease in eGFR, and certain eGFR threshold combined with decrement in eGFR. The eGFR< 60 ml/min/1.73m² was the most widely used definition or criterion for IKF, by which the pooled incidence rate of IKF was 12.50 (95%CI: 9.00–17.36) per 1000 person years (PYs). The second most-studied outcome was a > 25% decrease in eGFR, followed by eGFR< 90 ml/min/1.73m², eGFR< 30 ml/min/1.73m² and a combination of eGFR threshold plus decreased eGFR. The reported incidence rates of IKF differ widely by different definitions of IKF. The highest pooled incidence was observed for those with > 25% decrease in eGFR, while the lowest was observed in those with eGFR < 30 ml/min/1.73m². Substantial heterogeneity was identified across most estimates.

Conclusion

Our study provides a comprehensive summary of eGFR-based definitions and incidence rates of IKF in PLWH, not only promoting our understanding of IKF, but also underscoring needs for a concerted action to unify definitions and outcomes of IKF and their applications in AIDS care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02721-x.

Tenofovir Disoproxil Fumarate-Associated Renal Dysfunction Among Adult People Living with HIV at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia, 2019: A Comparative Retrospective Cohort Study

BACKGROUND

The use of tenofovir disoproxil fumarate (TDF) has been reported to be a significant contributor to renal dysfunction. However, patients in Ethiopia may be different than in other parts of the world, and findings from such studies may not apply in this setting.

OBJECTIVE

This study aimed to assess TDF-associated renal dysfunction among adult people living with HIV (PLHIV) at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia.

METHODS

This retrospective cohort study included adult PLHIV between January 2015 and June 2019. The Chronic Kidney Disease Epidemiology (CKD-EPI) equation was used to estimate glomerular filtration rate (eGFR). Renal dysfunction was defined as eGFR <60 mL/min/1.73 m2. Data were entered into Epi Info™ 7 and analyzed by using SPSS® software version 20. The Kaplan-Meier method was used to estimate the survival curves. Cox proportional hazards models were used to identify predictors of renal dysfunction using a 95% confidence interval and p-value ≤ 0.05 as a statistical significance.

RESULTS

Out of 400 participants, 200 were TDF-based ART groups, and 200 were non-TDF-based ART groups. The incidence of renal dysfunction of TDF and the non-TDF group was 28.31 per 100 person-years (PYs) and 12.53 per 100 PYs, respectively. Adult PLHIV taking TDF-based regimens were 1.70 (adjusted HR = 1.70; 95% CI = 1.02-2.82) times at higher risk of renal dysfunction than non-TDF-based regimens. Age ≥55, diabetes mellitus, concurrent nephrotoxic drug use, and combined use of ritonavir-boosted protease inhibitors were also associated significantly with renal dysfunction.

CONCLUSION

The incidence rate of renal dysfunction among TDF users is higher than non-TDF users. Exposure to TDF is a significant risk of renal dysfunction in adult PLHIV. Clinicians should regularly monitor the renal function of adult PLHIV who are taking TDF.

Recovery of Tenofovir-induced Nephrotoxicity following Switch from Tenofovir Disoproxil Fumarate to Tenofovir Alafenamide in Human Immunodeficiency Virus-Positive Patients

Background

Tenofovir disoproxil fumarate (TDF)-induced nephrotoxicity is related to high plasma tenofovir concentrations. Tenofovir alafenamide (TAF) is a tenofovir prodrug with 90% lower plasma tenofovir concentrations. The aim of this study was to evaluate changes in tenofovir-induced nephrotoxicity in Human Immunodeficiency Virus (HIV)-positive patients who switched from TDF to TAF.

Materials and Methods

We identified all HIV-positive patients who switched from elvitegravir/cobicistat/emtricitabine/TDF to elvitegravir/cobicistat/emtricitabine/TAF at a tertiary hospital. We assessed tubulopathy and renal dysfunction before TDF administration, at the time TAF was used following at least 3 months of TDF use, and 3 months after TAF administration. Tubulopathy was defined by the presence of at least three abnormalities in fractional excretion of phosphate, fractional excretion of uric acid, urinary β2-microglobulin, urinary N-acetyl-β-D-glucosaminidase, glucosuria or proteinuria. Renal dysfunction was defined as decreased by more than 25% in the estimated glomerular filtration rate (eGFR) relative to baseline.

Results

In 80 patients, the mean eGFR was 96.8 mL/min/1.73 m² before administration of TDF, 81.2 (P <0.001) at the time of change to TAF, 90.9 (P <0.001) after TAF administration. Renal dysfunction occurred in 19 patients (23.8%) after TDF use for a median 15 months, 11 (57.9%) of these patients recovered from renal dysfunction after TAF administration. Six patients (7.5%) had tubulopathy before TDF administration, 36 (45.0%) after TDF administration (P <0.001), 12 (15.0%) after TAF administration (P = 0.002).

Conclusion

Tenofovir-induced nephrotoxicity in HIV-positive patients receiving TDF was mostly reversible after changing to TAF. Thus, TAF-containing regimens can be administered safely to HIV-positive patients with tenofovir-induced nephrotoxicity.

Effect of TDF-containing regimens on creatinine clearance in HIV patients in Namibia with a baseline CrCl <60ml/min; findings and implications

Background and aims: The advent of antiretroviral therapy (ART) and early diagnosis of the human immunodeficiency virus (HIV) has resulted in an appreciable reduction in morbidity and mortality among people infected with HIV. However, tenofovir disoproxil fumarate (TDF)-containing ART regimens are associated with a reduction in creatinine clearance (CrCl). No evaluation has been conducted in Namibia to date on the relationship between TDF-containing ART and CrCl among patients with moderate to severe reductions in CrCl to guide future practice. We aimed to address this.Methodology: Retrospective longitudinal study between January 2008 to December 2016 evaluating CrCl in patients with a baseline CrCl <60ml/min who were receiving TDF-containing ART in a leading hospital in Namibia. We identified patients who had experienced an improvement in CrCl and compared their characteristics with those whose CrCl did not improve. We assessed factors for an association with improvement in CrCl using binary logistic regression.Results: 389 patients were included, the majority were female (n = 294). Female vs. male assessments showed no difference in age (p = 0.340), weight (p = 0.920), number who experienced an improvement (105 vs 39, p = 0.349), or absence of improvement (189 vs. 56, p = 0.349). The improvement group (male and female) had a lower baseline CrCl (45.9 vs. 55.0, p < 0.001). The follow-up CrCl for the improvement and no improvement groups were 72.6 and 55.9 respectively. Multivariate analysis showed that the odds of improvement were: 0.905 (0.871-0.940, p < 0.001) for each unit rise in the baseline CrCl, and 0.904(0.880-0.923) for each year of follow-up.Conclusion: More improvement than decline in CrCl was observed. Improvement occurred more in patients with lower baseline CrCl, and occurred in the early period of ART with reduced odds of experiencing this with time. Our findings indicate that TDF may be used in patients with a low baseline CrCl.

Tenofovir nephrotoxicity among Asians living with HIV: review of the literature

Tenofovir disoproxil fumarate (TDF), prodrug of tenofovir (TFV), is one of the most widely used nucleotide reverse transcriptase inhibitors (NRTIs) for the treatment of HIV infection in resource-rich and resource-limited settings with proven efficacy and safety, and also for the treatment of hepatitis B infections. However, TDF can cause renal proximal tubular dysfunction and also reduces estimated glomerular filtration rate (eGFR) more than other NRTIs. To date, TDF-associated renal dysfunction is generally regarded as mild and tolerable. However, it is notable that low body weight is one of the risk factors for TFV nephrotoxicity and that Asians are generally of smaller body stature and can be susceptible to such nephrotoxicity, as shown in several cohort studies. Until tenofovir alafenamide (TAF), another prodrug of TFV with minimal renal toxicity, becomes widely accessible for people living with HIV and replaces TDF, it is warranted that physicians who prescribe TDF have a good understanding of TFV nephrotoxicity. This paper reviews recent literature on TFV nephrotoxicity among people living with HIV especially focusing on Asians who might be susceptible to TFV nephrotoxicity due to their lower body weight and discusses implications for clinical care and future directions.

Long term renal function in Asian HIV-1 infected adults receiving tenofovir disoproxil fumarate without protease inhibitors

OBJECTIVES

The risk of kidney dysfunction on the WHO recommended first line regimens containing tenofovir disoproxil fumarate (TDF) without protease inhibitors (PI) remains unclear in Asian patients, especially those with low body weight.

METHODS

Using data collected in a multicenter clinical trial in Thailand and proportional hazard regression models, we compared the risk of a >25% estimated glomerular filtration rate (eGFR) reduction in HIV naïve patients initiating TDF or zidovudine (AZT) containing non-PI regimen.

RESULTS

Of 640 patients included in the analysis, 461 (72%) received a TDF-containing regimen for a median 6.7 years and 179 (28%) an AZT-containing regimen for 6.5 years. The risk of a >25% eGFR reduction was not associated with treatment (HR 1.11, 95% CI 0.84-1.47, P = 0.46). In multivariate analysis, the risk of >25% eGFR reduction form baseline was associated with body weight at baseline (HR 2.12, 95% CI 1.48-3.02 for <48 kg patients and HR 1.64, 95% CI 1.20-2.25 for 48-59.9 kg patients, compared to those with >60 kg, P < 0.001) and hypertension (HR 4.03, 95% CI 2.0-8.0, P < 0.001). The effect of baseline weight on >25% eGFR reduction did not significantly vary with treatment (P = 0.27).

CONCLUSIONS

The risk of eGFR reduction was not higher on TDF- versus AZT-based non-PI regimens. Although the risk of eGFR reduction was greater for patients of lower body weight, this risk was not significantly increased by TDF.

Incidence and risk factors for tenofovir-associated nephrotoxicity among human immunodeficiency virus-infected patients in Korea

BACKGROUND/AIMS

Little is known about tenofovir disoproxil fumarate (TDF)-induced nephrotoxicity in human immunodeficiency virus (HIV)-infected patients in Korea. The objective of this study was to evaluate the incidence and risk factors of TDF-associated nephrotoxicity among HIV-infected patients in Korea.

METHODS

A single-center retrospective cohort study was conducted on HIVinfected patients in Korea. We included patients who had started TDF or abacavir (ABC)-based antiretroviral therapy (ART) between October 2006 and December 2014. Estimated glomerular filtration rate (eGFR) was estimated using the Chronic Kidney Disease-Epidemiology Collaboration equation. Renal dysfunction was defined as > 25% decrease of baseline eGFR. A propensity matched case-control study was conducted to compare renal dysfunction rates between the two groups. The risk factors of nephrotoxicity were analyzed by Cox regression analysis.

RESULTS

A total of 210 HIV-infected patients were included in the study, of which, 108 were TDF-based ART group and 102 were ABC-based ART group. Renal dysfunction occurred in 16 patients (14.8%) in the TDF group and 11 (10.8%) in the ABC group. Incidence of renal dysfunction of TDF and ABC group was 9.66 per 100 person-years (PYs) and 5.14 per 100 PYs, respectively (p = 0.176). In propensityscore-matched analysis, renal dysfunction rates were TDF 13.3% versus ABC 13.3% (p > 0.999). In multivariable analysis, Centers for Disease Control and Prevention clinical category C was a significant risk factor for renal dysfunction.

CONCLUSION

Approximately, 13% of HIV-infected patients treated with TDF had renal dysfunction. Advanced stage of HIV infection was a significant risk factor for renal dysfunction.

Reduced Kidney Function in Tenofovir Disoproxil Fumarate Based Regimen and Associated Factors: A Hospital Based Prospective Observational Study in Ethiopian Patients

Purpose

Tenofovir disoproxil fumarate (TDF), a drug broadly used in combination antiretroviral therapy, is associated with renal dysfunction but the prevalence varied from country to country and it is not known in Ethiopia. The objectives of this study were to assess the prevalence of renal dysfunction and risk factors associated with it and the mean change in estimated glomerular filtration rate in human immunodeficiency virus infected patients receiving TDF based antiretroviral regimen at Tikur Anbessa Specialized Hospital.

Method

It was a hospital based prospective cohort study. The study participants were treatment naïve HIV infected patients initiating TDF containing combination antiretroviral therapy or switched to it because of adverse events. Multivariable logistic analysis was used to identify variables which have significant association.

Result

A total of 63 study participants were studied, 16 (25.4%) of whom had fall in eGFR greater than 25% relative to baseline. Only age greater than 50 years, baseline CD4 count less than 200 cells/mm³, and baseline proteinuria were significantly associated with renal dysfunction in multivariable logistic regression. There was -8.4 ml/min/1.73m² mean change in estimated glomerular filtration rate relative to baseline at six months of study.

Conclusion

The renal dysfunction (defined as decline in eGFR greater than 25%) was found in a quarter of the study population. The long term impact and the clinical implication of it are not clear. Future prospective study is required with large sample size and long duration to ascertain the prevalence of decline greater than 25% in estimated glomerular filtration rate and its progression to chronic kidney disease.

Short-term Changes in Urine Beta 2 Microglobulin Following Recovery of Acute Kidney Injury Resulting From Snake Envenomation

Introduction

Urine β2 microglobulin (β2m) is a validated marker to diagnose sepsis and toxin-related acute kidney injury (AKI). In the current study, we used urine β2m as a potential marker to identify persistent tubular dysfunction following a clinical recovery from snake venom–related AKI.

Methods

A total of 42 patients who developed AKI following hemotoxic envenomation were followed up for a period of 6 months. Urine albumin excretion, estimated glomerular filtration rate (eGFR), and urine β2m levels were measured at 2 weeks, 3 months, and 6 months following discharge.

Results

At the end of 6 months of follow-up, 6 patients (14.3 %) progressed to chronic kidney disease (CKD) (eGFR < 60 ml and/or urine albumin excretion > 30 mg/d). The urine β2m levels were 1590 μg/l (interquartile range [IQR] 425–5260), 610 μg/l (IQR 210–1850), 850 μg/l (IQR 270–2780) at 2 weeks, 3 months, and 6 months, respectively (P = 0.020). The levels of urine β2m in the study population at the end of 6 months remained significantly higher compared with the levels in healthy control population (850 μg/l [IQR 270–2780] vs. 210 μg/l [IQR 150–480]; P = 0.001). The proportion of patients with urine β2m levels exceeding the 95th percentile of control population (>644 µg/l) during the 3 follow-up visits were 70.7% (n = 29), 48.8 % (n = 20), and 51.2% (n = 21). Similar trends were noticed in a sensitivity analysis, after excluding patients with CKD.

Conclusions

Urine β2m levels remain persistently elevated in approximately half of the individuals who recover from AKI due to snake envenomation.

Epidemiological, clinical, and laboratory factors associated with chronic kidney disease in Mexican HIV-infected patients

AIM

To determine the prevalence of chronic kidney disease (CKD) and the epidemiological, clinical, and laboratory factors associated with CKD in Mexican HIV-infected patients.

METHODS

Cross-sectional study. We included 274 patients with HIV/AIDS. CKD was defined by the estimated glomerular filtration rate (eGFR < 60 mL/min/1.73 m2 assessed by CKD-EPI) and albuminuria criteria from KDIGO guidelines. Clinical, epidemiological, and laboratory characteristics were compared between patients with and without CKD. The factors associated with CKD were assessed by logistic regression analysis.

RESULTS

The mean age was 41±11 years, and 72.3% of the patients were men. The global prevalence of CKD was 11.7% (n = 32); 7.2% (n = 20) were defined by eGFR criterion; 7.6% (n = 21), by the albuminuria criterion; and 3.2% (n = 9), by both CKD criteria. The most frequently observed stages of CKD were KDIGO G3A1 stage with 4.7% (n = 13), KDIGO G1A2 stage with 3.6% (n = 10) and KDIGO G3A2 stage with 1.7% (n = 5). The factors associated with CKD were use of abacavir/lamivudine (OR 3.2; 95% CI 1.1-8.9; p = 0.03), a CD4 lymphocyte count < 400 cells/µL (OR 2.6; 95% 1.03-6.4, p = 0.04), age (OR 1.1; 95% CI 1.04-1.2, p = 0.001) and albuminuria (OR 19.98; 95% CI: 5.5-72.2; p < 0.001).

CONCLUSIONS

CKD was a frequent complication in HIV-infected patients. These findings confirm the importance of screening and the early detection of CKD, as well as the importance of identifying and treating traditional and non-traditional risk factors associated with CKD.

Incidence and predictors of tenofovir disoproxil fumarate-induced renal impairment in HIV infected Nigerian patients

Introduction

The use of tenofovir disoproxil fumarate (TDF) in the treatment of HIV infection has been associated with renal dysfunction. In Nigeria, data on the incidence and risk factors of TDF nephrotoxicity is sparse. We determined the cumulative incidence of and risk factors for TDF-induced renal impairment in HIV-infected individuals accessing care at the antiretroviral therapy (ART) clinic of Jos University Teaching Hospital, Nigeria.

Methods

This retrospective cohort analysis included patients aged ≥16 years that initiated ART between January 2008 and December 2011. Renal impairment, defined as glomerular filtration rate GFR <60 mL/min/1.73 sqm using the Modification of Diet in Renal Disease (MDRD) equation was assessed at baseline and at 48 weeks on ART. Logistic regression was performed to determine factors associated with incident renal impairment.

Results

The mean age was 39±9 years, and 67.1% were female. The cumulative incidence of renal impairment among the TDF-exposed and TDF-unexposed groups was 4.6% and 2.3% respectively (p<0.001). TDF exposure was significantly associated with renal impairment [OR=2.0, 95%CI=(1.48-2.89), p<0.001] in bivariate analysis. In multivariate analysis, older age (aOR=1.06, 95%CI=(1.05-1.08), p<0.001), TDF exposure [aOR=1.85, 95%CI=(1.31-2.60), p<0.001] and co-morbidities [aOR=2.71, 95%CI=(1.72-4.25), p<0.001] were significantly associated with renal impairment.

Conclusion

TDF exposure, aging and comorbidities were predictors of renal toxicity among HIV positive patients. Regular monitoring of renal function in such high-risk individuals is recommended.

Effect of Cobicistat on Tenofovir Disoproxil Fumarate (TDF): What Is True for TAF May Also Be True for TDF

BACKGROUND

The dose of tenofovir alafenamide is reduced from 25 to 10 mg daily when given with boosting agents. However, such dose reduction has never been adopted for tenofovir disoproxil fumarate (TDF). In this study, we aim to quantify the effect of cobicistat (COBI) both on tenofovir concentrations and TDF durability in real life setting.

METHODS

HIV-positive patients receiving TDF-containing antiretroviral therapies with at least 1 assessment of tenofovir plasma trough concentrations were included in the study. Univariate and multivariate regression analyses were performed considering tenofovir concentration as the dependent variable and clinical characteristics as independent covariates. Subsequently, survival and Cox analyses were performed considering as the primary outcome TDF discontinuation for any reasons.

RESULTS

Patients were given TDF with protease inhibitors/ritonavir (n = 212), non-nucleoside reverse transcriptase inhibitors (n = 176), integrase inhibitors (dolutegravir or raltegravir, n = 46), or with elvitegravir/COBI (ELV/COBI) (n = 76). By multivariate analysis, concomitant antiretroviral therapies resulted significantly associated with tenofovir levels, with the highest drug concentrations measured in patients given ELV/COBI. By survival analysis, we found that patients given TDF with ELV/COBI had the lowest rate of drug durability. Overall, these patients had a 2.3-fold increased risk to experience TDF discontinuation.

CONCLUSIONS

Coadministration with COBI resulted in significantly higher tenofovir concentrations and higher TDF discontinuation compared with other antiretroviral regimens. Accordingly, the possibility that the lack of proper dose adjustment for TDF when given with COBI might have biased the safety comparisons with tenofovir alafenamide during registrative trials cannot be ruled out.

Prevalence and factors associated with chronic kidney disease and end-stage renal disease in HIV-1-infected Asian patients in Tokyo

This single-center cross-sectional study determined the prevalence and factors associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD) in HIV-1-infected Asian patients at the largest HIV clinic in Japan. HIV-1-infected patients who visited the clinic between September and December 2016 were analyzed. CKD was defined as estimated glomerular filtration rate of <60 ml/min/1.73 m² or proteinuria ≥1+, observed at least over three months. A logistic regression model was used to estimate the effects of various variables on CKD. The study included 1,990 patients; with 97% Asians, 34% aged of ≥50 years, and 94% had HIV-1 load <50 copies/ml. The median time from HIV-1 diagnosis to study enrollment and duration of ART were 9.1 years (IQR4.8–14.2) and 7.35 years (IQR3.28–12), respectively. CKD and ESRD were diagnosed in 256 (13%) and 9 (0.5%) patients, respectively. The prevalence of CKD was 18.6% for age 50–59, 28.5% for 60–69, and 47% for over 70. Older age, heavier body weight, diabetes mellitus, hypertension, and longer duration of ART, but not duration of TDF exposure, were associated with CKD. The traditional risk factors, rather than HIV-1-related variables, were associated with CKD, suggesting the importance of management of such comorbidities in maintenance of renal function.

Change in Renal Function among HIV-Infected Koreans Receiving Tenofovir Disoproxil Fumarate-Backbone Antiretroviral Therapy: A 3-Year Follow-Up Study

PURPOSE

Tenofovir disoproxil fumarate (TDF) is commonly prescribed as a fixed-dose, co-formulated antiretroviral drug for HIV-1 infection. The major concern of long-term TDF use is renal dysfunction. However, little is known about the long-term patterns of changes in renal function in HIV-infected Koreans receiving TDF.

MATERIALS AND METHODS

We prospectively followed 50 HIV-infected Koreans, performing laboratory tests every 3 months during the first year and every 6 months for the next 2 years. Urine N-acetyl-β-D-glucosaminidase (NAG) and plasma cystatin-C were measured using samples collected in the first year. Data on renal function were retrospectively collected on HIV-infected patients receiving first-line TDF (n=40) and in antiretroviral therapy (ART)-naïve patients (n=24) for 3 years. Renal function was evaluated as estimated glomerular filtration rate (eGFR) from serum creatinine [Modification of Diet in Renal Disease (MDRD)] and cystatin-C.

RESULTS

The eGFR (cystatin-C) showed significant changes from 0 to 48 wks (p=0.002), with the lowest levels at 24 wks (84.3±18.8 mL/min vs. 90.3±22.5 mL/min, p=0.021 by post hoc test). Urine NAG levels did not differ at 0, 12, 24, and 48 wks, although eGFR (MDRD) significantly decreased from 0 (98.7±18.9 mL/min/1.73 m²) to 144 wks (89.0±14.7 mL/min/1.73 m²) (p=0.010). The first-line TDF group had significantly lower eGFR (MDRD) than the ART-naïve group at 144 wks (89.7 mL/min/1.73 m² vs. 98.4 mL/min/1.73 m², p=0.036). Thirteen (26%) participants experienced a decrease in renal impairment of 10 mL/min/1.73 m² in eGFR (MDRD) at 144 wks.

CONCLUSION

These data suggest that clinically meaningful renal injury can develop in HIV-infected Koreans receiving long-term TDF.

Rediscovering Beta-2 Microglobulin As a Biomarker across the Spectrum of Kidney Diseases

There is currently an unmet need for better biomarkers across the spectrum of renal diseases. In this paper, we revisit the role of beta-2 microglobulin (β₂M) as a biomarker in patients with chronic kidney disease and end-stage renal disease. Prior to reviewing the numerous clinical studies in the area, we describe the basic biology of β₂M, focusing in particular on its role in maintaining the serum albumin levels and reclaiming the albumin in tubular fluid through the actions of the neonatal Fc receptor. Disorders of abnormal β₂M function arise as a result of altered binding of β₂M to its protein cofactors and the clinical manifestations are exemplified by rare human genetic conditions and mice knockouts. We highlight the utility of β₂M as a predictor of renal function and clinical outcomes in recent large database studies against predictions made by recently developed whole body population kinetic models. Furthermore, we discuss recent animal data suggesting that contrary to textbook dogma urinary β₂M may be a marker for glomerular rather than tubular pathology. We review the existing literature about β₂M as a biomarker in patients receiving renal replacement therapy, with particular emphasis on large outcome trials. We note emerging proteomic data suggesting that β₂M is a promising marker of chronic allograft nephropathy. Finally, we present data about the role of β₂M as a biomarker in a number of non-renal diseases. The goal of this comprehensive review is to direct attention to the multifaceted role of β₂M as a biomarker, and its exciting biology in order to propose the next steps required to bring this recently rediscovered biomarker into the twenty-first century.

Steady-state pharmacokinetics of tenofovir disoproxil fumarate in human immunodeficiency virus-infected Chinese patients

BACKGROUND

The pharmacokinetic (PK) profile of tenofovir disoproxil fumarate in Chinese adults infected with HIV is unknown.

METHODS

A pilot, prospective, open-label study was performed to investigate the steady-state PK profile of tenofovir disoproxil fumarate in 15 Chinese HIV-infected patients among whom eight patients were treated with 300 mg tenofovir disoproxil fumarate, 300 mg lamivudine and 400/100 mg lopinavir/ritonavir, and seven with 300 mg tenofovir disoproxil fumarate, 300 mg lamivudine and 400 mg nevirapine. The plasma concentrations of tenofovir over the 24-h dosing interval were determined by HPLC. The PK parameters were calculated using the non-compartmental model in WinNonlin software.

RESULTS

The PK parameters of tenofovir in the 15 patients were determined as follows (mean ± SD): AUC_{(0-24 h)}, 4074.7 ± 1551.9 ng•h/mL; C_max,ss, 447.1 ± 217.4 ng/mL; C_trough,ss, 98.7 ± 36.7 ng/mL; t_max,ss, 1.3 ± 0.4 h; plasma t_1/2, 21.8 ± 7.6 h; and CL_ss/F, 45.8 ± 13.0 L/h.

CONCLUSION

Tenofovir demonstrated slower elimination rate and increased plasma concentration in Chinese patients compared to previously published data from Caucasian or African subjects, which may be associated with the higher incidences of renal and bone resorption dysfunction observed in our patient population. Clinicians should be cautious of the differing PK characteristics of tenofovir among people of different races.

Effect of Tenofovir Disoproxil Fumarate on Incidence of Chronic Kidney Disease and Rate of Estimated Glomerular Filtration Rate Decrement in HIV-1-Infected Treatment-Naïve Asian Patients: Results from 12-Year Observational Cohort

Little evidence is available for the incidence of chronic kidney disease (CKD) and rate of estimated glomerular filtration rate (eGFR) decrement among Asians with low body weight who are susceptible to tenofovir disoproxil fumarate (TDF) nephrotoxicity. In this 12-year observational cohort in Tokyo, we examined 1383 treatment-naïve HIV-1-infected Asians [720 started TDF-containing (TDF group) and 663 started non-TDF-containing (control) combination antiretroviral therapy (cART)]. The CKD incidence was calculated, and the effect of TDF use on CKD development was estimated using logistic regression. The eGFR slopes, before and after cART initiation, were estimated using mixed-effects linear spline models. Most patients were males (median weight, 62.6 kg; 83% started ritonavir-boosted protease inhibitors; median observation duration, 5.08 years). CKD developed in 150 patients (10.8%), with an incidence of 20.6 per 1000 person-years [confidence interval (95% CI), 17.6–24.2]. None developed end-stage renal disease. TDF use was associated with CKD [odds ratio (OR), 1.8; 95% CI, 1.00–3.13; p = 0.052]. The cumulative mean loss in the TDF group, relative to the control, increased over time after 1, 4, and 8 years of TDF exposure (−3.8, −5.5, and −9.0 mL/min/1.73 m², respectively; p < 0.0001). The eGFR rapidly declined during the first 3 months of cART, particularly in the TDF group (−26.4 vs. −7.4 mL/min/1.73 m²/year in the control). In the TDF group, cART introduction was significantly associated with a faster rate of eGFR decline (from −0.44 to −2.11 mL/min/1.73 m²/year; p = 0.010), whereas in the control, the difference was not significant. For HIV-1-infected Asian patients with low body weight, TDF-containing cART is associated with CKD and faster eGFR declines.

The association between urinary liver-type fatty acid-binding protein and chronic kidney disease classification in HIV-infected Japanese patients

BACKGROUND

Renal dysfunction is recognized with increasing frequency among the noninfectious comorbidities associated with human immunodeficiency virus (HIV) infection. Urinary liver-type fatty acid-binding protein (L-FABP) has been shown to be a new biomarker to screen for not only tubulointerstitial damage but also kidney dysfunction.

METHODS

We performed a cross-sectional study to determine the association between the urinary L-FABP and chronic kidney disease (CKD) among 77 HIV-infected Japanese patients by backward-stepwise multivariable logistic regression.

RESULTS

The prevalence of individuals in the low risk was 80 %. Urinary L-FABP level was not associated with antiretroviral therapy and tenofovir disoproxil fumarate. On the other hand, urinary L-FABP level was independently associated with the CKD classification.

CONCLUSION

Urinary L-FABP may be used as an adjunct to diagnose the CKD stage.

Plasma tenofovir trough concentrations are associated with renal dysfunction in Japanese patients with HIV infection: a retrospective cohort study

Background

Plasma tenofovir (TFV) trough concentrations may be relevant for tenofovir disoproxil fumarate (TDF)-induced renal dysfunction. The purpose of this study was to determine the association between plasma TFV trough concentrations and TDF-induced renal dysfunction in Japanese patients with human immunodeficiency virus (HIV) infection.

Methods

A 48-week, retrospective cohort study was performed with Japanese patients with HIV infection who started a TDF-containing combination antiretroviral therapy regimen. Plasma TFV trough concentrations were obtained at steady state. The following variables were included in the analysis: sex, age, body weight, body mass index (BMI), serum creatinine, CD4+ cell count, HIV-RNA, concomitant medications, comorbidities, plasma TFV trough concentrations, and estimated glomerular filtration rate (eGFR). For comparisons of variables, we used Mann-Whitney U tests or Fisher’s exact tests. Then, variables associated with renal dysfunction in the univariate analysis were entered into correlation analysis.

Results

The analysis included 11 patients. The rate of decrease in eGFR was significantly correlated with body weight (Spearman correlation = −0.645, p = 0.041), BMI (Spearman correlation = −0.682, p = 0.031), and plasma TFV trough concentrations (Spearman correlation = 0.709, p = 0.025).

Conclusions

Despite the small sample size, our findings suggest that higher plasma TFV trough concentrations may cause TDF-induced renal dysfunction. To prevent TDF-induced renal dysfunction, we propose that individual monitoring of plasma TFV trough concentrations should be performed in Japanese patients with HIV infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s40780-016-0056-5) contains supplementary material, which is available to authorized users.

Effects of a switch from tenofovir- to abacavir-based antiretroviral therapy, with or without atazanavir, on renal function

Introduction

Tenofovir disoproxil fumarate (TDF)–associated renal dysfunction may abate when TDF is replaced with abacavir (ABC). The extent to which the third drug atazanavir contributes to renal dysfunction is unclear.

Methods

A retrospective analysis was conducted on adults who had plasma viral load (pVL)<200 copies/mL for≥six months while receiving TDF/lamivudine (3TC) – or TDF/emtricitabine (FTC)–based antiretroviral therapy (ART), then switched to ABC/3TC while retaining the third drug in the ART regimen. CD4, pVL, creatinine, estimated glomerular filtration rate (eGFR), serum phosphorus, urine albumin to creatinine ratio and serum lipids were compared between pre-switch baseline and 3, 6 and 12 months after the switch to ABC.

Results

A total of 286 patients switched from TDF to ABC between 2004 and 2014: 232 (81%) male, median age 48 years (interquartile range (IQR) 42, 56). The third drug was atazanavir (± ritonavir) in 141 (49%) cases. The pVL was<50 copies/mL in 93 to 96% at all time points. Median serum creatinine was 93 µmol/L (IQR 80–111) at baseline and decreased to 88 µmol/L (IQR 78–98) at 12 months after the switch to ABC. Median eGFR increased from 74 (IQR 60–88) mL/min at baseline to 80 mL/min (IQR 69–89) at 12 months. Results were not significantly different between patients on atazanavir versus those on another third drug.

Conclusions

Viral suppression was maintained among patients who switched from TDF/3TC or TDF/FTC to ABC/3TC. Serum creatinine and eGFR improved up to 12 months after switching to ABC/3TC, irrespective of whether or not patients were also receiving atazanavir±ritonavir.

Urinary β2 microglobulin can predict tenofovir disoproxil fumarate-related renal dysfunction in HIV-1-infected patients who initiate tenofovir disoproxil fumarate-containing antiretroviral therapy

OBJECTIVE

In nephrotoxicity induced by tenofovir disoproxil fumarate (TDF), tubular dysfunction precedes the decline in GFR, suggesting that tubular markers are more sensitive than estimated glomerular filtration rate (eGFR). The hypothesis that urinary β2 microglobulin (β2 M), a tubular function marker, can predict TDF-renal dysfunction in HIV-1-infected patients was tested.

DESIGN

A single-center observational study.

METHODS

The inclusion criteria were: HIV-1-infected patients who started TDF-containing antiretroviral therapy from 2004 to 2013, urinary β2 M after and closest to the day of TDF initiation within 180 days (termed 'β2 M after TDF') was measured. The associations between 'β2 M after TDF' and four renal end points (>10 ml/min per 1.73 m decrement in eGFR relative to baseline, >20 decrement, >25% decrement, and eGFR < 60) were estimated with logistic regression model. The association between 'β2 M after TDF' and longitudinal changes in eGFR after initiation of TDF was estimated with a mixed-model.

RESULTS

A total 655 study patients were analyzed (96% men, median age 38, median CD4 238 cells/μl, 63% treatment naïve). The median baseline eGFR was 117 ml/min per 1.73 m (IQR 110-125), and the median duration of TDF use was 3.32 years (IQR 2.02-5.31). 'β2 M after TDF' was significantly associated with more than 20 decrement in eGFR (P = 0.024) and more than 25% decrement (P = 0.014), and was marginally associated with eGFR less than 60 (P = 0.076). It was also significantly associated with the longitudinal eGFR after initiation of TDF (P < 0.0001). 'β2 M after TDF' of 1700 μg/l was identified as the optimal cutoff value for the prediction of longitudinal eGFR.

CONCLUSIONS

Urinary β2 M measured within 180 days after initiation of TDF predicts renal dysfunction related to long-term TDF use.

Is Abnormal Urine Protein/Osmolality Ratio Associated with Abnormal Renal Function in Patients Receiving Tenofovir Disoproxil Fumarate?

BACKGROUND

Risk factors for and optimal surveillance of renal dysfunction in patients on tenofovir disoproxil fumarate (TDF) remain unclear. We investigated whether a urine protein-osmolality (P/O) ratio would be associated with renal dysfunction in HIV-infected persons on TDF.

METHODS

This retrospective, single-center study investigated the relationship between parameters of renal function (estimated glomerular filtration rate (eGFR) and P/O-ratio) and risk factors for development of kidney dysfunction. Subjects were HIV-infected adults receiving TDF with at least one urinalysis and serum creatinine performed between 2010 and 2013. Regression analyses were used to analyze risk factors associated with abnormal P/O-ratio and abnormal eGFR during TDF therapy.

RESULTS

Patients were predominately male (81%); (65%) were Caucasian. Mean age was 45.1(±11.8) years; median [IQR] TDF duration was 3.3 years. [1.5-7.6]. Median CD4+ T cell count and HIV viral load were 451 cells/μL [267.5-721.5] and 62 copies/mL [0-40,150], respectively. Abnormal P/O-ratio was not associated with low eGFR. 68% of subjects had an abnormal P/O-ratio and 9% had low eGFR. Duration of TDF use, age, diabetes and hypertension were associated with renal dysfunction in this study. After adjustment for age, subjects on TDF > 5 years had almost a four-fold increased likelihood of having an abnormal P/O-ratio than subjects on TDF for < 1yr (OR 3.9; 95% CI 1.2-14.0; p = 0.024).

CONCLUSION

Abnormal P/O-ratio is common in HIV-infected patients on TDF but was not significantly associated with low eGFR, suggesting that abnormal P/O-ratio may be a very early biomarker of decreased renal function in HIV infected patients.

Tenofovir monotherapy for hepatitis B after 1 year does not produce renal dysfunction, but is associated with hyperparathyroidism not related to vitamin D

INTRODUCTION

Viral hepatitis B (VHB) represents a major public health problem. Studies from HIV multidrug patients have associated the use of tenofovir disoproxil fumarate (TDF) with renal dysfunction and phosphate wasting.

OBJECTIVE

The aim of this study was to examine the effect of year-long TDF monotherapy on renal function in VHB patients.

PATIENTS AND METHODS

We evaluated adult patients diagnosed with VHB before treatment initiation (T0), and after 3 and 12 months (T3 and T12) of TDF initiation. Estimated glomerular filtration rate (eGFR) was estimated by serum cystatin C and creatinine. In addition, urinary electrolytes and tubular biomarkers (cystatin C, β2-microglobulin and neutrophil gelatinase-associated lipocalin) were analyzed, as well as parathyroid hormone (PTH) and 25(OH)vitamin D levels.

RESULTS

After 1 year, 32 patients completed the study, 22 (68.7%) men and 12 (37.5%) Whites, mean age 44.1±12.0 years. We found that serum electrolytes were similar at baseline and 3 or 12 months after initiation of TDF monotherapy. In addition, urinary fractional excretions of electrolytes as well as proteinuria, albuminuria, urinary β2-microglobulin, and urinary cystatin C showed no significant differences across the treatment timeline. There were also no statistical differences in the eGFR. There was a statistically significant increase in the PTH (Friedman's test, P=0.012), but the 25(OH)vitamin D levels were in the normal range in the beginning and did not change at the follow-up. Moreover, there was no correlation between the initial levels of vitamin D and the corresponding increases in the PTH values.

CONCLUSION

If used as monotherapy in hepatitis B patients for a 12-month period, TDF is not associated with changes in either eGFR or a panel of urinary biomarkers. Serum and urinary electrolytes also remained unchanged. Of note, a significant increase in the PTH was found, although not related to the 25(OH)vitamin D initial status.

Drug Transporter Genetic Variants Are Not Associated with TDF-Related Renal Dysfunction in Patients with HIV-1 Infection: A Pharmacogenetic Study

Objective

To investigate whether single nucleotide polymorphisms (SNP) of drug transporter proteins for TDF is a risk factor for TDF-related renal function decrement.

Methods

This study investigated the association between 3 SNPs (ABCC2–24, 1249, and ABCB1 2677), which are shown to be associated with TDF-induced tubulopathy, and clinically important renal outcomes (>10ml/min/1.73m² decrement in eGFR relative to baseline, >25% decrement in eGFR, and eGFR <60ml/min/1.73m²) in 703 HIV-1-infected Japanese patients who initiated TDF-containing antiretroviral therapy (ART). Genotyping was performed by allelic discrimination using TaqMan 5’-nuclease assays.

Results

95% of the study patients were males and 66% were treatment-naïve, with median CD4 count of 249/μl, median baseline eGFR of 96ml/min/1.73m² (IQR 84.6–109.2), and median exposure to TDF of 3.66 years (IQR 1.93–5.59). The frequencies of genotypes at -24, 1249 of ABCC2, and 2677 of ABCB1 were neither different between patients with decrement in eGFR of >10ml/min/1.73m² and those without such decrement (ABCC2: -24, p = 0.53, 1249, p = 0.68; ABCB1: 2677, p = 0.74), nor between those without and with the other two renal outcomes (>25% decrement: ABCC2: -24, p = 0.83, 1249, p = 0.97, ABCB1: 2677, p = 0.40; eGFR <60ml/min/1.73m²: ABCC2: -24, p = 0.51, 1249, p = 0.81, ABCB1: 2677, p = 0.94). Logistic regression analysis showed that the risk genotype of the three SNPs were not associated with any of the three renal outcomes, respectively. Logistic regression model that applied either dominant, recessive, or additive model yielded the same results.

Conclusions

SNPs of the drug transporters for TDF are not associated with clinically important renal outcomes in patients who initiated TDF-containing ART.

Raltegravir and Abacavir/Lamivudine in Japanese Treatment-Naïve and Treatment-Experienced Patients with HIV Infection: a 48-Week Retrospective Pilot Analysis

Abacavir/lamivudine (ABC/3TC) is a nucleoside reverse transcriptase inhibitor used for treating human immunodeficiency viral (HIV) infections. Hypersensitivity reactions such as skin eruptions caused by ABC are well-known, but rarely occur in Asians. Raltegravir (RAL) is an integrase strand transfer inhibitor, that is now increasingly, used for treating HIV infections because it has few adverse effects. This retrospective analysis assessed the efficacy and safety of combined ABC/3TC and RAL in both treatment-naïve and -experienced Japanese patients with HIV infections. In all 11 treatment-naïve patients (100%), virological suppression to undetectable level was achieved. Liver transaminases, renal function, and serum lipid profiles showed no exacerbations up to 48 weeks of treatment. In 12 patients who were switched from previous regimens to ABC/3TC and RAL, HIV viral load was undetectable in 11 patients (91.6%), but remained detectable in 1 patient with poor adherence. Major reasons for switching regimens to ABC/3TC and RAL were hyperlipidemia and nausea. After switching, these adverse effects improved, and no new adverse effects were observed. Despite the small number of participants in this study, the results support the combination of ABC/3TC and RAL as a possible treatment choice in Japanese individuals with HIV-infection.

Factors associated with daily tenofovir exposure in Thai subjects taking combination antiretroviral therapy

Tenofovir (TFV) exposure is associated with antiretroviral efficacy and risk of kidney disease. There is evidence of high interindividual variability of the pharmacokinetics of TFV. The effect of several clinical conditions on the pharmacokinetics of TFV has been observed and may partly explain its variability. We assessed factors influencing the pharmacokinetics of TFV in Thai patients. Thirty participants (50% female) taking efavirenz- or ritonavir-boosted protease inhibitor-based regimens were investigated. Intensive pharmacokinetic sampling was performed over 24 h. Multivariate geometric mean regression models adjusted for covariates with p ≤ 0.2 in univariate analysis were developed. The median age was 41 years. Five participants [three taking a protease inhibitor (PI) and two taking efavirenz (EFV)] had mild renal dysfunction [estimated glomerular filtration rate (eGFR) 60-90 ml/min/1.73 m(2); range 72-89]. TFV AUC0-24 was 23% (95% CI 1-49%; p=0.04) higher in those taking PI vs. EFV, 39% (95% CI 5-84%; p=0.02) higher in those with mild renal dysfunction, and reduced by 16% (95% CI 5-26%; p=0.008) with each 10 kg body weight increase, after adjusting for sex and duration of TFV exposure. In PI-treated subjects TFV AUC0-24 increased by 3% (0.3-6%; p=0.03) for each mg·h/liter increase in ritonavir (RTV) AUC0-24 after adjusting for sex, weight, mild renal impairment, and proximal renal tubular dysfunction. Significantly higher TFV exposures were independently associated with PI regimens, mild renal impairment, lower body weight, and increasing RTV AUC0-24. Clinicians should be aware of the effect of these factors on TFV exposure when this drug is prescribed.

Week 120 efficacy of tenofovir, lamivudine and lopinavir/r-based second-line antiretroviral therapy in treatment-experienced HIV patients

BACKGROUND

Tenofovir (TDF) and ritonavir-boosted lopinavir (LPV/r) were not introduced to China as second-line medications until 2009. The efficacy and safety of TDF/3TC/LPV/r based second-line regimen have not been evaluated in Chinese HIV patients who failed first-line regimens.

METHODS

This was a multicenter cohort study recruiting patients from Beijing, Shanghai, Guangdong, and Henan provinces between November 2008 and January 2010. Eighty HIV infected patients failing first-line regimens with serum creatinine lower than 1.5 times the upper limit of normal received TDF+ lamivudine (3TC)+ LPV/r were followed up for 120 weeks. CD4 cell count, viral load, and estimated glomerular filtration rate (eGFR) were monitored at each visit.

RESULTS

At baseline, 31.2% and 48.8% of patients had moderate/high-level resistance to TDF and 3TC, respectively; while 2.5% of patients had only low-level resistance to LPV/r. During 120 weeks of follow-up, virological suppression rate reached over 70% (<40 copies/ml) and 90% (<400 copies/ml), and median CD4 cell count increased from 157 cells/μL at baseline to 307 cells/μL at week 120. Baseline drug-resistance mutations had no impact on the efficacy of second-line antiretroviral therapy. Median eGFR dropped from 104.7 ml/min/1.73m2 at baseline to 95.6 ml/min/1.73m2 at week 24 and then recovered after week 96.

CONCLUSION

This study for the first time demonstrated that TDF+ 3TC+ LPV/r was efficacious as second-line regimen with acceptable nephrotoxicity profiles in patients who failed zidovudine or stavudine based first-line regimens in China.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00872417.

Renal safety of coformulated tenofovir/emtricitabine vs other nucleoside analogues in combination therapy in antiretroviral-naive patients aged 50 years or older in Spain: The TRIP study

OBJECTIVES

Our aim is to describe the impact of emtricitabine (FTC)/tenofovir (TDF) versus other nucleoside reverse transcriptase inhibitor (NRTIs)-based regimens on renal function of human immunodeficiency virus (HIV) naïve patients >50 years old who started combination antiretroviral therapy (cART).

DESIGN

National, retrospective cohort analysis of patients >50 years old when they started cART (January 1, 2006-December 31, 2009).

METHODS

We compared renal safety (changes in estimated glomerular filtration rate [eGFR] during the first year, and time to renal events during 4 years of follow-up) in FTC/TDF versus non-FTC/TDF users. Among FTC/TDF users, we compared protease inhibitors vs non-nucleoside reverse transcriptase inhibitors and Lopinavir/ritonavir vs Efavirenz.

RESULTS

We included 103 patients: median age: 54.9 years, 84% males, median CD4 count 247 cells/μl, median viral load 4.7 log; median follow up 18 months (max: 48 months); 73 started with FTC/TDF and 30 with other NRTIs. Change in eGFR was significantly worse for ritonavir-boosted lopinavir (LPV/r) vs efavirenz (EFV) users in the FTC/TDF group (71.2 vs 98.9 ml/min/1.73 m(2) at month 12, P < 0.05). The risk of renal events (progression to an Chronic Kidney Disease Epidemiology Collaboration value < 60 ml/min/1.73 m(2) in subjects with baseline values >60) was comparable for FTC/TDF users and non users, but was higher and almost significant for LPV/r as compared to EFV users in the FTC/TDF group (adjusted hazard ratio 6.1, 95% CI 0.8-45.5).

CONCLUSIONS

In our study with a population of HIV infected subjects ≥ 50 years old, renal safety was similar for FTC/TDF and other NRTI-based regimens, but worse for LPV/r as compared to other regimens.

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.

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.

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.

Higher risk of renal impairment associated with tenofovir use amongst people living with HIV in India: a comparative cohort analysis between Western India and United Kingdom

Background

Data on the renal safety of Tenofovir (TDF) in Low and Middle Income Countries (LMICs) is scarce. We compared development of various forms of renal impairment with use of TDF-containing antiretroviral therapy (ART) between a cohort from the Institute of Infectious Diseases (IID) Pune, Western India and the Royal Free Hospital (RFH) London, UK.

Methods

This is a retrospective analysis of change in estimated glomerular filtration rates (eGFRs) at 6, 12 and 24 months post TDF initiation using the Modification of Diet in Renal Disease (MDRD) equation. In people living with Human Immunodeficiency virus (PLHIV) with pre-TDF eGFR > 90 ml/min/1.73 m² time to development of and factors associated with progression to eGFR < 60 ml/min/1.73 m² were calculated using standard survival methods.

Results

A total of 574 (59% Caucasian) at the RFH, and 708 (100% Indian ethnicity) PLHIV from IID were included. Baseline median eGFR were similar; RFH 102 (IQR 89, 117), IID 100 (82, 119). At 24 months, mean (SD) decline in eGFR was -7(21) at RFH (p < 0.0001) and -7(40) at IID (p = 0.001). Amongst those with pre-TDF eGFR > 90 ml/min/1.73 m² PLHIV at IID were more likely to develop an eGFR < 60 ml/min/1.73 m² (aHR = 7.6 [95% CI 3.4, 17.4] p < 0.0001) and had a faster rate of progression estimated using Kaplan Meier methods. Risk factors included age (per 10 years older: aHR = 2.21 [1.6, 3.0] p < 0.0001) and receiving concomitant ritonavir boosted Protease Inhibitor (PI/r) (aHR = 2.4 [1.2, 4.8] p = 0.01).

Conclusions

There is higher frequency of treatment limiting renal impairment events amongst PLHIV receiving TDF in Western India. As TDF scale up progresses, programs need to develop capacity for monitoring and treatment of renal impairment associated with TDF.

High prevalence of illicit drug use in men who have sex with men with HIV-1 infection in Japan

OBJECTIVE

To examine the prevalence of illicit drug use among men who have sex with men (MSM) with HIV-1 infection in Japan, where the life-time prevalence of illicit drug use in the general population is only 2.9%.

DESIGN

A single-center cross-sectional study at a large HIV clinic in Tokyo, which treats approximately 15% of HIV-1 infected patients in Japan.

METHODS

The prevalence of illicit drug use and the association of characteristics and social demographics of the patients with illicit drug use were examined. Patients who visited the clinic for the first time from 2005 to 2010 were enrolled. Relevant variables were collected using a structured interview and from the medical records. Multivariate logistic regression analyses were applied to estimate the odds of association of MSM over non-MSM HIV-infected patients with illicit drug use.

RESULTS

1,196 patients were enrolled. They were mostly Japanese men of relatively young age. Illicit drug use (including injection drugs) was reported by 35% of the patients (by 40% of MSM), and 4% were IDU while 5% were on methamphetamine. 2% of the population was arrested due to illicit drugs. MSM was significantly associated with illicit drug use (adjusted OR = 4.60; 95% CI, 2.88-7.36; p<0.01). Subgroup analysis of the patients stratified by three age groups (≤ 30, 31 to 40, and >40) showed that the odds of association of MSM with illicit drug use was the strongest in the youngest age group (≤ 30 years: adjusted OR = 7.56; 95% CI, 2.86-20.0; p<0.01), followed by the oldest (>40 years: adjusted OR = 6.15; 95% CI, 2.40-15.8; p<0.01), and the weakest in the group aged 31 to 40 (adjusted OR = 3.39; 95% CI, 1.73-6.63; p<0.01).

CONCLUSIONS

The prevalence of illicit drug use is high among MSM patients with HIV-1 infection in Japan. Effective intervention for illicit drug use in this population is warranted.

Low body weight in females is a risk factor for increased tenofovir exposure and drug-related adverse events

Treatment with tenofovir sometimes leads to non-reversible kidney and/or bone diseases. Factors associated with these drug-related adverse events are poorly characterized. Our objective was to investigate such factors in patients treated long term with daily tenofovir. One-hundred Caucasian HIV-positive patients with basal creatinine clearance >80 mL/min treated with tenofovir for at least 6 months and with at least one assessment of tenofovir plasma trough concentrations were considered. Tenofovir-associated adverse events were defined as the appearance of pathological proteinuria, worsening of renal function or bone demineralization. By multivariate regression analysis, we found that serum creatinine (p = 0.003) and body weight (p = 0.002) were the factors independently associated with plasma tenofovir concentrations. In particular, women with body weight<50 kg had significantly higher plasma tenofovir concentrations than those weighting >50 Kg (160±93 vs.71±52 ng/mL, p<0.001). High tenofovir plasma trough concentrations and the age of the patients were independently associated with the development of drug-related kidney and bone toxicity. In this retrospective study we have shown that HIV-infected women with low body weight are at risk to be exposed to high tenofovir plasma trough concentrations, ultimately resulting in a significant hazard to develop long-term tenofovir complications.

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.

Tenofovir use and urinary biomarkers among HIV-infected women in the Women's Interagency HIV Study (WIHS)

BACKGROUND

Tenofovir (TDF) has been associated with renal tubular injury. Biomarkers that signal early tubular dysfunction are needed because creatinine rise lags behind TDF-associated kidney dysfunction. We examined several urinary biomarkers to determine if rises accompanying TDF initiation preceded creatinine changes.

METHODS

Three urinary biomarkers of tubular impairment--neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D-glucosaminidase (NAG), and β-2-microglobulin (β2MG)--were measured across 3 time points (one pre-TDF visit and 2 post-TDF visits) in 132 HIV-positive women from the Women's Interagency HIV Study. Women initiating highly active antiretroviral therapy (HAART) containing TDF were propensity score matched to women initiating HAART without TDF and women not on HAART.

RESULTS

There were no differences between groups for NGAL or NAG, but β2MG was 19 times more likely to be elevated among TDF users at the second post-TDF visit compared with non-TDF users at the pre-TDF visit (P < 0.01). History of proteinuria was associated with elevated NGAL (P < 0.01). Factors associated with elevated NAG were glomerular filtration rate <60 mL/minute, history of proteinuria, hepatitis C (P < 0.01 for all), and diabetes mellitus (P = 0.05). Factors associated with increased odds of elevated β2MG were HIV RNA >100,000 copies/mL, hepatitis C, boosted protease inhibitor use, and glomerular filtration rate <60 mL/minute (P ≤ 0.01 for all).

CONCLUSIONS

β2MG levels are elevated in women on TDF, indicating probable early renal dysfunction. Biomarker elevation is additionally associated with baseline chronic kidney disease, uncontrolled viremia, and boosted protease inhibitor use. Future studies are needed to explore urinary biomarker thresholds in identifying treated HIV-infected individuals at risk for renal dysfunction.

Switching tenofovir/emtricitabine plus lopinavir/r to raltegravir plus Darunavir/r in patients with suppressed viral load did not result in improvement of renal function but could sustain viral suppression: a randomized multicenter trial

Background

Whether tenofovir nephrotoxicity is reversible after its withdrawal is unknown. Furthermore, there are no data on the viral efficacy of raltegravir (RAL) plus ritonavir-boosted Darunavir (DRV/r) in patients with suppressed viral load.

Methods

This multicenter, randomized trial compared renal function and viral efficacy in patients with suppressed viral load treated with RAL+DRV/r and ritonavir-boosted lopinavir (LPV/r) plus tenofovir/emtricitabine (TVD), who had been previously on LPV/r+TVD. The primary endpoint was the proportion of patients with >10% improvement in estimated glomerular filtration rate (eGFR) at 48 weeks calculated with Cockcroft-Gault equation.

Results

58 randomized and treatment-exposed patients were analyzed (28 on RAL+DRV/r and 30 on LPV/r+TVD). Greater than 10% improvement in eGFR was noted in 6 (25%) out of 24 with RAL+DRV/r and 3 (11%) of 28 with LPV/r+TVD, and the difference was not statistically significant (p=0.272, 95% CI -0.067 to 0.354). Sensitivity analyses using three other equations for eGFR showed the same results. Urinary β2 microglobulin, a sensitive marker of tenofovir tubulopathy, significantly improved with RAL+DRV/r than with LPV/r+TVD (-271 versus -64 µg/gCr, p=0.026). Per protocol analysis showed that the HIV-RNA was <50 copies/mL at week 48 in all patients of both arms (24 in RAL+DRV and 29 in LPV/r+TVD).

Conclusions

Switching LPV/r+TVD to RAL+DRV/r did not significantly increase the proportion of patients who showed >10% improvement in renal function among those with relatively preserved eGFR. However, the switch improved urinary β2 microglobulin, suggesting that discontinuation of TDF might be beneficial in the long-term. RAL+DRV/r showed favorable viral efficacy in patients with suppressed viral load.

Trial Registration

ClinicalTrials.gov NCT01294761 http://clinicaltrials.gov/ct2/show/NCT01294761?term=SPARE&rank=2, Umin Clinical Trials Registry UMIN000005116 http://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000006083&language=J)

Once-daily darunavir/ritonavir and abacavir/lamivudine versus tenofovir/emtricitabine for treatment-naïve patients with a baseline viral load of more than 100 000 copies/ml

The efficacy and safety of fixed-dose abacavir/lamivudine against tenofovir/emtricitabine, both with once-daily darunavir/ritonavir, was examined in 80 treatment-naïve patients with a baseline HIV-1 viral load of more than 100 000 copies/ml. The time to virologic failure by 48 weeks was not different between the two groups. The percentage of patients with viral suppression was not significantly different with per protocol population. Tenofovir/emtricitabine showed better tolerability; more patients on abacavir/lamivudine changed regimen than those on tenofovir/emtricitabine. A randomized trial to elucidate the efficacy and safety of these two regimens is warranted.

Abacavir/lamivudine versus tenofovir/emtricitabine with atazanavir/ritonavir for treatment-naive Japanese patients with HIV-1 infection: a randomized multicenter trial

OBJECTIVE

To compare the efficacy and safety of fixed-dose abacavir/lamivudine (ABC/3TC) and tenofovir/emtricitabine (TDF/FTC) with ritonavir-boosted atazanavir (ATV/r) in treatment-naïve Japanese patients with HIV-1 infection.

METHODS

A 96-week multicenter, randomized, open-label, parallel group pilot study was conducted. The endpoints were times to virologic failure, safety event and regimen modification.

RESULTS

109 patients were enrolled and randomly allocated (54 patients received ABC/3TC and 55 patients received TDF/FTC). All randomized subjects were analyzed. The time to virologic failure was not significantly different between the two arms by 96 weeks (HR, 2.09; 95% CI, 0.72-6.13; p=0.178). Both regimens showed favorable viral efficacy, as in the intention-to-treat population, 72.2% (ABC/3TC) and 78.2% (TDF/FTC) of the patients had an HIV-1 viral load <50 copies/mL at 96 weeks. The time to the first grade 3 or 4 adverse event and the time to the first regimen modification were not significantly different between the two arms (adverse event: HR 0.66; 95% CI, 0.25-1.75, p=0.407) (regimen modification: HR 1.03; 95% CI, 0.33-3.19, p=0.964). Both regimens were also well-tolerated, as only 11.1% (ABC/3TC) and 10.9% (TDF/FTC) of the patients discontinued the allocated regimen by 96 weeks. Clinically suspected abacavir-associated hypersensitivity reactions occurred in only one (1.9%) patient in the ABC/3TC arm.

CONCLUSION

Although insufficiently powered to show non-inferiority of viral efficacy of ABC/3TC relative to TDF/FTC, this pilot trial suggested that ABC/3TC with ATV/r is a safe and efficacious initial regimen for HLA-B*5701-negative patients, such as the Japanese population.

Cancer and the 'other' noncommunicable chronic diseases in older people living with HIV/AIDS in resource-limited settings: a challenge to success

OBJECTIVE

There is considerable research around the morbidity and mortality related to noncommunicable diseases (NCDs), particularly cardiovascular disease and diabetes, among people living with HIV/AIDS (PLWHA) in resource-richer settings. Less is known about the burden and appropriate management of NCDs, particularly 'other' NCDs including cancer, renal, pulmonary, neurocognitive and mental health conditions, among older PLWHA in resource-limited settings (RLSs). We undertook a literature review of these other NCDs to explore what is currently known about them and identify areas of further research.

METHODS

Systematic literature review of published manuscripts and selected conference abstracts and reports.

RESULTS

Although there is growing recognition of the importance of these NCDs among the aging population of PLWHA in RLSs, significant gaps remain in understanding the epidemiology and risk factors among older PLWHA in these settings. Even more concerning is the limited available evidence for effective and feasible approaches to prevention, screening and treatment of these conditions. The burden of these NCDs is related to both the aging of the population of PLWHA and an increased risk due to HIV infection, other comorbidities associated with HIV infection or transmission risk and underlying risk factors in the general community. Results from resource-richer settings and RLSs highlight malignancies, neurocognitive and mental health as well as renal disease as the most significant challenges currently and likely to increase in the future.

CONCLUSION

Although some lessons can be taken from the growing experience with NCDs in older PLWHA in resource-richer settings, additional research is needed to better understand their risk and impact and identify optimal models of care to effectively address this challenge in the areas where the majority of older PLWHA will be receiving care.

Renal safety of tenofovir containing antiretroviral regimen in a Singapore cohort

BACKGROUND

Tenofovirdisoproxilfumarate (TDF) is a nucleotide analogue widely recommended in international HIV treatment guidelines. The association of TDF and renal dysfunction has remained an area of interest.

FINDINGS

We conducted a retrospective review of all patients on TDF from July 2007 to December 2009 in our institution and evaluated their renal function. Absolute change of creatinine clearance (CLCr) using Cockroft-Gault equation from baseline was calculated at 6, 12, 18 and 24 months. Overall, 226 patients were included in the study. Ninety percent were male. The median age was 46 yrs old (23-82), median weight was 60 kg (IQR 53.75-68), median CD4 count was 127 cells/mm3 (IQR 38-258) and median CLCr 82.7 mL/min (IQR 71.4-101.7) on initiation of TDF. The median decline of CLCr from baseline was -3.9 ml/min (IQR -12.3 to 7.6), and -3.6 ml/min (IQR -12.4 to 6.7) at 12 (n = 102), 24 months (n = 75) respectively. Eighteen of 226 patients had a decline in renal function to </=50 ml/min. Majority of which had an improvement of CLCr on follow up. Only 80% of patients ever received monitoring of renal function.

CONCLUSION

While we noted renal toxicity to be rare and transient among our cohort receiving TDF as part of their ARV regimen, these results reflect the short term renal effects of TDF given that ARV treatment is lifelong. Given that laboratory monitoring may be difficult to implement in many situations, future prospective studies looking into an evidence based algorithm for less frequent renal function monitoring than current guideline recommendations may be helpful.