Kidney tubular abnormalities in the absence of impaired glomerular function in HIV patients treated with tenofovir

Renal dysfunction during treatment of chronic hepatitis B with tenofovir disoproxyl fumarate and associated risk factors

OBJECTIVES

To analyze the evolution of glomerular filtration rate (GFR) and the presence of renal tubular dysfunction during the treatment of chronic hepatitis B virus (HBV) infection with tenofovir disoproxil fumarate (TDF) and to determine the risk factors involved.

METHODS

Retrospective cohort observational study of adults with chronic hepatitis B. Exclusion: hepatitis C virus-HBV coinfection, diabetes, baseline GFR less than 60 ml/min. Measurements of serum and urinary creatinine and phosphate; urinary albumin, retinol-binding protein (RBP) and neutrophil gelatinase-associated lipocalin (NGAL) were performed. Univariate and multivariate analyses tracked factors associated with worsening GFR.

RESULTS

A total of 120 individuals were included: 35% NAÏVE (G1); 49.2% HBV using TDF (G2); 15.8% HBV-HIV using TDF (G3); 63.3% men; 60.8% white; 30% hypertensive. Average age was 50.5 years (SD ± 12.9 years). Reactive HBeAg predominated in G3 ( P  < 0.001) and cirrhosis in G2 ( P  < 0.036). NGAL was elevated in 5.3% of cases (G1 = 3.2%; G2 = 8.7%; G3 = 0%; P  = 0.582), RBP in 6.7% (G1, G3 = 0%; G2 = 13.6%; P  = 0.012), urinary phosphate/creatinine ratio in 16.2% (G1 = 15.2%; G2 = 14.5%; G3 = 23.5%; P  = 0.842) and urinary albumin/creatinine ratio in 12.9% (G1 = 12.2%; G2 = 10.7%; G3 = 21.1%; P  = 0.494). Worsening of renal function occurred in 22.5% of the population (G1 = 11.9%; G2 = 28.8%; G3 = 26.3%; P  = 0.122), independently associated only with systemic arterial hypertension [adjusted odds ratio (AOR) = 4.14; P  = 0.008], but not to TDF (AOR = 2.66; P  = 0.110) or male sex (AOR = 2.39; P  = 0.135). However, the concomitance of these variables generated a high estimated risk for this outcome (51%).

CONCLUSIONS

Renal tubular dysfunction was uncommon according to NGAL, RBP or urinary phosphate/creatinine ratio. TDF was not an independent factor for worsening renal function, significantly associated only with systemic arterial hypertension. However, in hypertensive men, the use of TDF should be monitored.

Acquired disorders of phosphaturia: Beyond tumor-induced osteomalacia

Phosphate is an integral part of human cellular structure and function. Though most recognised disorders of phosphaturia are genetic in origin, phosphate loss due to acquired conditions is commonly encountered in clinical practice. Acquired hypophosphatemia is most commonly due to renal phosphate wasting and can produce significant morbidity. It also heralds future kidney damage, and continued exposure can lead to progressive kidney injury and potentially renal failure. These conditions are a diverse group of disorders with common shared mechanisms causing loss of phosphate in the urine. Renal phosphate loss can occur as an isolated entity or as a part of generalised proximal tubular dysfunction, i.e., Fanconi's syndrome. An insight into the pathophysiological mechanisms of acquired phosphaturia can help clinicians monitor their patients better and avoid potential harms.

The role of ABCC10/MRP7 in anti-cancer drug resistance and beyond

Multidrug resistance protein 7 (MRP7), also known as ATP-binding cassette (ABC) transporter subfamily C10 (ABCC10), is an ABC transporter that was first identified in 2001. ABCC10/MRP7 is a 171 kDa protein located on the basolateral membrane of cells. ABCC10/MRP7 consists of three transmembrane domains and two nucleotide binding domains. It mediates multidrug resistance of tumor cells to a variety of anticancer drugs by increasing drug efflux and results in reducing intracellular drug accumulation. The transport substrates of ABCC10/MRP7 include antineoplastic drugs such as taxanes, vinca alkaloids, and epothilone B, as well as endobiotics such as leukotriene C4 (LTC4) and estradiol 17 β-D-glucuronide. A variety of ABCC10/MRP7 inhibitors, including cepharanthine, imatinib, erlotinib, tariquidar, and sildenafil, can reverse ABCC10/MRP7-mediated MDR. Additionally, the presence or absence of ABCC10/MRP7 is also closely related to renal tubular dysfunction, obesity, and other diseases. In this review, we discuss: 1) Structure and functions of ABCC10/MRP7; 2) Known substrates and inhibitors of ABCC10/MRP7 and their potential therapeutic applications in cancer; and 3) Role of ABCC10/MRP7 in non-cancerous diseases.

Tenofovir-Induced Fanconi Syndrome Presenting with Life-Threatening Hypokalemia: Review of the Literature and Recommendations for Early Detection

Tenofovir disoproxil fumarate (TDF) is a nucleotide reverse transcriptase inhibitor that has been widely used for the treatment of patients with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections. Despite the excellent safety records of this regimen, a few cases of acute renal failure and Fanconi syndrome have been reported among HIV patients exposed to TDF. However, in the HBV monoinfection scenario, only five cases of TDF-associated Fanconi syndrome have been reported thus far, two of them providing a confirmatory kidney biopsy. Here, we describe the case of a 68-year-old woman with chronic hepatitis B (CHB) who developed TDF-induced Fanconi syndrome that reverted after TDF withdrawal from tenofovir alafenamide. Though the overall risk of TDF-associated severe renal toxicity in HBV patients appears to be negligible, both glomerular and tubular functions should be monitored in patients exposed to TDF.

Fanconi Syndrome in Patients With Human Immunodeficiency Virus Treated With Tenofovir-Based Antiretroviral Therapy: A Systematic Literature Review

OBJECTIVE

Several cases of Fanconi syndrome (FS), a severe form of nephrotoxicity, have been reported in patients with HIV on tenofovir-containing antiretroviral therapy. A systematic review of the published literature on tenofovir-related FS in patients with HIV was conducted.

DATA SOURCES

PubMed and Embase were queried to identify articles in English published between January 2005 and June 2023, reporting tenofovir-related FS in adults with HIV. Preclinical studies, conference/poster abstracts, commentaries and responses, and review papers were excluded.

STUDY SELECTION AND DATA EXTRACTION

Of the 256 articles screened, 57 met the inclusion criteria. These comprised 37 case reports, 11 case series, 1 cross-sectional study, 1 case-control study, 4 cohort studies, 1 single-arm open-label clinical trial, 1 sub-analysis of clinical trials, and 1 pooled analysis of clinical trials.

DATA SYNTHESIS

Among 56 cases on which information was abstracted, median age at FS diagnosis was 50 years, 51.8% were men, and duration of tenofovir use ranged from 6 weeks to 11 years. Ritonavir was co-prescribed in almost half the cases. In observational and interventional studies, incidence of FS was low. Many studies reported resolution of FS symptoms after tenofovir discontinuation. All FS occurrences were identified in those on tenofovir disoproxil fumarate (TDF), except for one patient on tenofovir alafenamide (TAF).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Continuous monitoring of signs and symptoms of renal and bone toxicity is essential for patients with HIV on tenofovir-containing therapy.

CONCLUSIONS

Occurrence of FS is low in patients with HIV treated with tenofovir-based regimens. Concomitant use of ritonavir may increase risk of FS. TAF may be a safer alternative than TDF in terms of nephrotoxicity.

Improved bone and renal safety in younger tenofovir disoproxil fumarate experienced chronic hepatitis B patients after switching to tenofovir alafenamide or entecavir

INTRODUCTION AND OBJECTIVES

Renal and bone impairment has been reported in chronic hepatitis B (CHB) patients receiving long-term tenofovir disoproxil fumarate (TDF) therapy. This study aimed to assess the incidence of renal and bone impairment in CHB patients with long-term TDF therapy and to identify the changes in bone mineral density (BMD) and renal function in these patients after switching to entecavir (ETV) or tenofovir alafenamide (TAF).

MATERIALS AND METHODS

This retrospective study collected clinical data from CHB patients who received TDF monotherapy over 96 weeks. The changes in BMD and renal function were analyzed after 96 weeks of switching antiviral regimens (ETV or TAF) or maintenance TDF.

RESULTS

At baseline, 154 patients receiving TDF monotherapy over 96 weeks were enrolled, with a younger median age of 36.75 years, 35.1% (54/154) of patients experienced elevated urinary β2 microglobulin and 20.1% (31/154) of patients had reduced hip BMD (T<-1). At week 96, among the 123 patients with baseline normal BMD, patients who maintained TDF (n=85) had experienced a decrease in hip BMD, while patients who switched antiviral regimens (n=38) experienced an increase (-13.97% vs 2.34%, p<0.05). Among patients with a baseline reduced BMD (n=31), the alterations in BMD were similar in patients who maintained TDF (n=5) and those who switched antiviral regimens (n=26) (-15.81% vs 7.35%, p<0.05). Irrespective of baseline BMD status, renal function decreased significantly in patients who maintained TDF and improved in patients who switched antiviral regimens.

CONCLUSIONS

Younger CHB patients on long-term TDF therapy are at high risk for bone and renal impairment, with the risk being reduced when switched to ETV or TAF.

Bone and Renal Health in Infants With or Without Breastmilk Exposure to Tenofovir-Based Maternal Antiretroviral Treatment in the PROMISE Randomized Trial

BACKGROUND

We assessed bone and kidney outcomes in infants randomized postdelivery as mother-infant pairs within the IMPAACT PROMISE trial to maternal tenofovir disoproxil fumarate-based antiretroviral treatment (mART) or infant nevirapine prophylaxis (iNVP) to prevent breastfeeding HIV transmission.

METHODS

Infants were coenrolled in the P1084s substudy on randomization day and followed through Week 74. Lumbar spine bone mineral content (LS-BMC) was assessed at entry (6-21 age days) and Week 26 by dual-energy x-ray absorptiometry. Creatinine clearance (CrCl) was calculated at entry; Weeks 10, 26, and 74. Student t tests compared mean LS-BMC and CrCl at Week 26 and mean change from entry between arms.

RESULTS

Of 400 enrolled infants, the mean (SD; n) for entry LS-BMC was 1.68 g (0.35; n = 363) and CrCl was 64.2 mL/min/1.73 m 2 (24.6; n = 357). At Week 26, 98% of infants were breastfeeding and 96% on their assigned HIV prevention strategy. The mean (SD) Week 26 LS-BMC was 2.64 g (0.48) for mART and 2.77 g (0.44) for iNVP; mean difference (95% confidence interval [CI]) -0.13 g (-0.22 to -0.04), P = 0.007, n = 375/398 (94%). Mean absolute (-0.14 g [-0.23 to -0.06]) and percent (-10.88% [-18.53 to -3.23]) increase in LS-BMC from entry was smaller for mART than iNVP. At Week 26, the mean (SD) CrCl was 130.0 mL/min/1.73 m 2 (34.9) for mART vs. 126.1 mL/min/1.73 m 2 (30.0) for iNVP; mean difference (95% CI) 3.8 (-3.0 to 10.7), P = 0.27, n = 349/398 (88%).

CONCLUSION

Week 26 mean LS-BMC was lower in infants in the mART group compared with the iNVP group. However, this difference (∼0.23 g) was less than one-half SD, considered potentially clinically relevant. No infant renal safety concerns were observed.

A prospective cohort study of renal function and bone turnover in adults with hepatitis B virus (HBV)-HIV co-infection with high prevalence of tenofovir-based antiretroviral therapy use

OBJECTIVE

Tenofovir disoproxil fumarate (TDF) is a common component of antiretroviral therapy in hepatitis B virus (HBV)-HIV co-infected adults but few studies have evaluated worsening renal function and bone turnover, known effects of TDF.

METHODS

Adults from eight North American sites were enrolled in this cohort study. Research assessments were conducted at entry and every 24 weeks for ≤192 weeks. Bone markers were tested at baseline, week 96 and week 192 from stored serum. We evaluated changes in markers of renal function and bone turnover over time and potential contributing factors.

RESULTS

A total of 115 patients were prospectively followed; median age 49 years, 91% male and 52% non-Hispanic Black. Duration of HIV was 20.5 years. TDF use ranged from 80% to 92% throughout follow-up. Estimated glomerular filtration rate (eGFR) (ml/min/1.73m² ) decreased from 87.1 to 79.9 over 192 weeks (p < 0.001); however, the prevalence of eGFR <60 ml/min/1.73m² did not appear to differ over time (always <16%; p = 0.43). From baseline to week 192, procollagen type I N-terminal propeptide (P1NP) (146.7 to 130.5 ng/ml; p = 0.001), osteocalcin (14.4 to 10.2 ng/ml; p < 0.001) and C-terminal telopeptides of type I collagen (CTX-1) (373 to 273 pg/ml; p < 0.001) decreased. Younger age, male sex and overweight/obesity versus normal weight predicted a decrease in eGRF. Black race, healthy weight versus underweight, advanced fibrosis, undetectable HBV DNA, and lower parathyroid hormone level predicted worsening bone turnover.

CONCLUSION

In this HBV-HIV cohort with high prevalence of TDF use, several biomarkers of renal function and bone turnover indicated worsening status over approximately 4 years, highlighting the importance of clinical awareness in co-infected adults.

Safety considerations in the management of hepatitis C and HIV co-infection

INTRODUCTION

Both HCV and HIV are highly prevalent infections with current estimates of 57 and 38 million people infected worldwide, respectively. Oral antivirals can be curative for HCV and rescue HIV patients from disease progression. Dual therapy in coinfected patients requires expertise.

AREAS COVERED

Four major issues challenge dual HCV and HIV treatment, including overlapping drug-related side effects, hepatitis B reactivation, immune reconstitution inflammatory syndromes (IRIS), and drug-drug interactions (DDI). A search was conducted in PubMed from January 2010 to March 2023.

EXPERT OPINION

The advent of second-generation direct-acting antivirals (DDA) that depict higher antiviral potency, fewer side effects, pangenotypic activity and are co-formulated has expanded the indication of HCV therapy and particularly in HIV-coinfected individuals. Sequential initiation of antiretrovirals (ARV) followed by DAA is generally preferred to start dual treatment concomitantly. Close monitoring of rare episodes of HBV reactivation and IRIS is warranted. The most frequent DDI between DAA and ARV affect drug metabolism by CYP450 induction/inhibition, leading to abnormal drug exposures. Throughout this mechanism interact most HCV and HIV protease inhibitors and non-nucleoside polymerase inhibitors. Exposure to some HIV and HCV nucleos(t)ide analogues (e.g. tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters and requires special attention in patients with renal insufficiency.

Integration of High-Throughput Imaging and Multiparametric Metabolic Profiling Reveals a Mitochondrial Mechanism of Tenofovir Toxicity

Nephrotoxicity is a major cause of kidney disease and failure in drug development, but understanding of cellular mechanisms is limited, highlighting the need for better experimental models and methodological approaches. Most nephrotoxins damage the proximal tubule (PT), causing functional impairment of solute reabsorption and systemic metabolic complications. The antiviral drug tenofovir disoproxil fumarate (TDF) is an archetypal nephrotoxin, inducing mitochondrial abnormalities and urinary solute wasting, for reasons that were previously unclear. Here, we developed an automated, high-throughput imaging pipeline to screen the effects of TDF on solute transport and mitochondrial morphology in human-derived RPTEC/TERT1 cells, and leveraged this to generate realistic models of functional toxicity. By applying multiparametric metabolic profiling-including oxygen consumption measurements, metabolomics, and transcriptomics-we elucidated a highly robust molecular fingerprint of TDF exposure. Crucially, we identified that the active metabolite inhibits complex V (ATP synthase), and that TDF treatment causes rapid, dose-dependent loss of complex V activity and expression. Moreover, we found evidence of complex V suppression in kidney biopsies from humans with TDF toxicity. Thus, we demonstrate an effective and convenient experimental approach to screen for disease relevant functional defects in kidney cells in vitro, and reveal a new paradigm for understanding the pathogenesis of a substantial cause of nephrotoxicity.

Risk Factors of Renal Tubular Dysfunction in Thai People Living with HIV Receiving Tenofovir Disoproxil Fumarate

Tenofovir disoproxil fumarate (TDF) associates with renal tubular dysfunction (RTD) in some people living with HIV (PLWH). We studied clinical and genetic factors associated with RTD in Thai PLWH receiving TDF. RTD was diagnosed in 13 of 65 (20%) patients. The median (interquartile range) age and CD4 cell counts were 43.8 (40.4-50.9) years and 554 (437-716) cells/mm³, respectively. The median duration of TDF use was 46.9 (31.5-54.1) months. Univariate logistic regression demonstrated body mass index (BMI), concomitant use of protease inhibitor (PI), hyperlipidemia, and homozygous C/C SNP rs1059751 of ABCC4 gene as predisposing factors of RTD. In multivariate model, concomitant use of PI [adjusted odds ratio (aOR) 11.39; 95% confidence interval (CI), 1.59- 81.56; P = 0.015], hyperlipidemia (aOR 8.59; 95% CI, 1.46-50.40; P = 0.017), and BMI (aOR 0.76; 95% CI, 0.59-0.98; P = 0.037) remained associated with RTD in patients receiving TDF. PLWH receiving TDF with the presence of these factors should be closely monitored for RTD.

Proximal tubular renal dysfunction among HIV infected patients on Tenofovir versus Tenofovir sparing regimen in western Kenya

Introduction

Tenofovir Disoproxil Fumarate (TDF) is the most widely used Anti-Retroviral Therapy (ART) drug due to its potency, safety profile and World Health Organization (WHO) recommendation. TDF causes proximal tubular renal dysfunction (PTRD) leading to Fanconi syndrome, acute kidney injury and chronic kidney disease. Modest rates (2–4%) of TDF related toxicity based on estimated Glomerular Filtration Rate (GFR) have been described, while TDF-induced PTRD has been reported to be 22%. TDF toxicity is more likely among African patients, it is reversible and TDF may be renal dosed in patients with dysfunction. The objective of this study was to assess proximal tubular renal dysfunction, global renal function, and their determinants among patients on TDF versus TDF-sparing regimen.

Methods

This was a cross-sectional study among people living with HIV/AIDS (PLWHA) attending the Academic Model Providing Access to Healthcare (AMPATH) program. The primary outcome of interest in this study was PTRD while the secondary outcome of interest was estimated GFR. PTRD was defined as any two of beta-2 microglobulin in urine, metabolic acidosis, normoglycemic glucosuria and fractional excretion of phosphate. Student’s t-test, chi-square and their non-parametric equivalents were used to test for statistical significance. Univariate and multivariate logistic regression analysis was carried out.

Results

A total of 516 participants were included in the final analysis, 261 on TDF while 255 were on TDF-sparing regimens. The mean (SD) age of all participants was 41.5 (12.6) years with majority being female (60.3%). The proportion of PTRD was 10.0% versus 3.1% in the TDF compared to TDF-sparing group (P<0.001). Mean estimated GFR was 112.8 (21.5) vs 109.7 (21.9) ml/min/1.73mm³ (P = 0.20) for the TDF compared to TDF-sparing group. TDF users were more likely to have PTRD compared to non-TDF users, adjusted Odds Ratio (AOR) 3.0, 95% CI 1.12 to 7.75.

Conclusion

There was significant PTRD in the TDF compared to TDF-sparing group without significant difference in estimated GFR. The clinical significance of these findings may not be clear in the short term.

Maternal and infant renal safety following tenofovir disoproxil fumarate exposure during pregnancy in a randomized control trial

BACKGROUND

Tenofovir disoproxil fumarate (TDF) in combination with other antiretroviral (ARV) drugs has been in clinical use for HIV treatment since its approval in 2001. Although the effectiveness of TDF in preventing perinatal HIV infection is well established, information about renal safety during pregnancy is still limited.

TRIAL DESIGN

The IMPAACT PROMISE study was an open-label, strategy trial that randomized pregnant women to one of three arms: TDF based antiretroviral therapy (ART), zidovudine (ZDV) based ART, and ZDV alone (standard of care at start of enrollment). The P1084s substudy was a nested, comparative study of renal outcomes in women and their infants.

METHODS

PROMISE participants (n = 3543) were assessed for renal dysfunction using calculated creatinine clearance (CrCl) at study entry (> 14 weeks gestation), delivery, and postpartum weeks 6, 26, and 74. Of these women, 479 were enrolled in the P1084s substudy that also assessed maternal calcium and phosphate as well as infant calculated CrCl, calcium, and phosphate at birth.

RESULTS

Among the 1338 women who could be randomized to TDF, less than 1% had a baseline calculated CrCl below 80 mL/min. The mean (standard deviation) maternal calculated CrCl at delivery in the TDF-ART arm [147.0 mL/min (51.4)] was lower than the ZDV-ART [155.0 mL/min (43.3); primary comparison] and the ZDV Alone [158.5 mL/min (45.0)] arms; the mean differences (95% confidence interval) were - 8.0 mL/min (- 14.5, - 1.5) and - 11.5 mL/min (- 18.0, - 4.9), respectively. The TDF-ART arm had lower mean maternal phosphate at delivery compared with the ZDV-ART [- 0.14 mg/dL (- 0.28, - 0.01)] and the ZDV Alone [- 0.17 mg/dL (- 0.31, - 0.02)] arms, and a greater percentage of maternal hypophosphatemia at delivery (4.23%) compared with the ZDV-ART (1.38%) and the ZDV Alone (1.46%) arms. Maternal calcium was similar between arms. In infants, mean calculated CrCl, calcium, and phosphate at birth were similar between arms (all CIs included 0).

CONCLUSIONS

Although mean maternal calculated CrCl at Delivery was lower in the TDF-ART arm, the difference between arms is unlikely to be clinically significant. During pregnancy, the TDF-ART regimen had no observed safety concerns for maternal or infant renal function.

TRIAL REGISTRATION

NCT01061151 on 10/02/2010 for PROMISE (1077BF). NCT01066858 on 10/02/2010 for P1084s.

Drug-Induced Acute Kidney Injury

Medications are a common cause of AKI especially for patients admitted to hospital wards and the intensive care unit. Although drug-related kidney injury occurs through different mechanisms, this review will focus on three specific types of tubulointerstitial injury. Direct acute tubular injury develops from several medications, which are toxic to various cellular functions. Their excretory pathways through the proximal tubules contribute further to AKI. Drug-induced AKI may also develop through induction of inflammation within the tubulointerstitium. Medications can elicit a T cell-mediated immune response that promotes the development of acute interstitial nephritis leading to AKI. Although less common, a third pathway to kidney injury results from the insolubility of drugs in the urine leading to their precipitation as crystals within distal tubular lumens, causing a crystalline-related AKI. Intratubular obstruction, direct tubular injury, and localized inflammation lead to AKI. Clinicians should be familiar with the pathogenesis and clinical-pathologic manifestations of these forms of kidney injury. Prevention and treatment of AKI relies on understanding the pathogenesis and judiciously using these agents in settings where AKI risk is high.

Proximal tubular dysfunction in pregnant women receiving tenofovir disoproxil fumarate to prevent mother-to-child transmission of hepatitis B virus

BACKGROUND

Data evaluating the risk of proximal tubular dysfunction in women receiving tenofovir disoproxil fumarate for the prevention of mother-to-child transmission (PMTCT) of HBV are scarce.

OBJECTIVES

To assess the risk of proximal tubulopathy in pregnant women receiving tenofovir disoproxil fumarate for PMTCT of HBV.

PATIENTS AND METHODS

We used urine samples collected from HBV monoinfected pregnant women who participated in a Phase III, multicentre, randomized, double-blind, placebo-controlled clinical trial assessing a tenofovir disoproxil fumarate short course from 28 weeks gestational age (28-wk-GA) to 2 months post-partum (2-months-PP) for PMTCT of HBV in Thailand. Markers of tubular dysfunction, including retinol binding protein, kidney injury molecule-1, α1-microglobuin and β2-microglobulin, were assayed at 28- and 32-wk-GA and 2-months-PP visits. Proximal tubulopathy was defined as the presence of ≥2 of the following: tubular proteinuria, euglycaemic glycosuria and increased urinary phosphate.

RESULTS

A total of 291 women participated in the study. No kidney-related adverse events were severe, and none led to tenofovir disoproxil fumarate discontinuation. At 2-months-PP, 3 of the 120 (3%) evaluated women in the tenofovir disoproxil fumarate group experienced proximal tubulopathy versus 3 of 125 (2%) in the placebo group (P  = 1.00). None of the six women met the criteria for proximal tubulopathy at 12-months-PP but proteinuria persisted in three of them. No growth abnormalities were found at 1 year of age in infants born to mothers with proximal tubulopathy at 2-months-PP.

CONCLUSIONS

In these HBV-infected pregnant and breastfeeding women, tenofovir disoproxil fumarate administered from 28-wk-GA to 2-months-PP was not associated with a higher risk of proximal tubulopathy.

Drug toxicity in the proximal tubule: new models, methods and mechanisms

The proximal tubule (PT) reabsorbs most of the glomerular filtrate and plays an important role in the uptake, metabolism and excretion of xenobiotics. Some therapeutic drugs are harmful to the PT, and resulting nephrotoxicity is thought to be responsible for approximately 1 in 6 of cases of children hospitalized with acute kidney injury (AKI). Clinically, PT dysfunction leads to urinary wasting of important solutes normally reabsorbed by this nephron segment, leading to systemic complications such as bone demineralization and a clinical scenario known as the renal Fanconi syndrome (RFS). While PT defects can be diagnosed using a combination of blood and urine markers, including urinary excretion of low molecular weight proteins (LMWP), standardized definitions of what constitutes clinically significant toxicity are lacking, and identifying which patients will go on to develop progressive loss of kidney function remains a major challenge. In addition, much of our understanding of cellular mechanisms of drug toxicity is still limited, partly due to the constraints of available cell and animal models. However, advances in new and more sophisticated in vitro models of the PT, along with the application of high-content analytical methods that can provide readouts more relevant to the clinical manifestations of nephrotoxicity, are beginning to extend our knowledge. Such technical progress should help in discovering new biomarkers that can better detect nephrotoxicity earlier and predict its long-term consequences, and herald a new era of more personalized medicine.

Trends of age-related non-communicable diseases in people living with HIV and comparison with uninfected controls: A nationwide population-based study in South Korea

OBJECTIVES

We aim to compare the trends of non-communicable diseases (NCDs) and death among people living with HIV (PLWH) and uninfected controls in South Korea.

METHODS

We identified PLWH from a nationwide database of all Korean citizens enrolled from 1 January 2004 to 31 December 2016. A control cohort was randomly selected for PLWH by frequency matching for age and sex in a 20:1 ratio. To compare NCD trends between the groups, adjusted incidence rate ratios for outcomes across ages, calendar years and times after HIV diagnosis were calculated.

RESULTS

We included 14 134 PLWH and 282 039 controls in this study; 58.5% of PLWH and 36.4% of the controls were diagnosed with at least one NCD. The incidence rates of cancers, chronic kidney disease, depression, osteoporosis, diabetes and dyslipidaemia were higher in PLWH than in the controls, whereas those of cardiovascular disease, heart failure, ischaemic stroke and hypertension were lower in PLWH. Relative risks (RRs) for NCDs in PLWH were higher than controls in younger age groups. Trends in the RRs of NCDs tended to increase with the calendar year for PLWH vs. controls and either stabilized or decreased with time after HIV diagnosis. The RR of death from PLWH has decreased with the calendar year, but showed a tendency to rise again after 2014 and was significant at the early stage of HIV diagnosis.

CONCLUSIONS

Although the RR of each NCD in PLWH showed variable trends compared with that in controls, NCDs in PLWH have been increasingly prevalent.

Update on the management and treatment of viral hepatitis

This review aims to summarize the current evidence on the treatment of viral hepatitis, focusing on its clinical management. Also, future treatment options and areas of potential research interest are detailed. PubMed and Scopus databases were searched for primary studies published within the last ten years. Keywords included hepatitis A virus, hepatitis B virus (HBV), hepatitis C virus, hepatitis D virus (HDV), hepatitis E virus, and treatment. Outcomes reported in the studies were summarized, tabulated, and synthesized. Significant advances in viral hepatitis treatment were accomplished, such as the advent of curative therapies for hepatitis C and the development and improvement of hepatitis A, hepatitis B, and hepatitis E vaccination. Drugs that cure hepatitis B, going beyond viral suppression, are so far unavailable; however, targeted antiviral drugs against HBV (immunomodulatory therapies and gene silencing technologies) are promising approaches to eradicating the virus. Ultimately, high vaccination coverage and large-scale test-and-treat programmes with high screening rates may eliminate viral hepatitis and mitigate their burden on health systems. The development of curative hepatitis C treatment renewed the enthusiasm for curing hepatitis B, albeit further investigation is required. Novel therapeutic options targeting HDV life cycle are currently under clinical investigation.

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.

A novel evidence of serial changes of bone mineral density in chronic hepatitis B patients treated with entecavir

BACKGROUND AND AIMS

Tenofovir disoproxil fumarate (TDF) and Entecavir (ETV) are commonly used for patients with chronic hepatitis B (CHB), and renal or bone toxicity are possible concerns. This study is to evaluate the renal and bone effect of TDF compared with ETV in CHB patients.

METHODS

This is a retrospective study at Kaohsiung Chung-Gung memorial hospital, Taiwan, from June 2013 to December 2018. Patients with CHB were prescribed with TDF or ETV for 3 years or above. Renal function was assessed at 12-week intervals. Dual-energy X-ray absorptiometry scans of the spine and femurs were performed at 48-week intervals. The propensity score analysis was conducted to balance the baseline characteristics of patients in both treatment groups.

RESULTS

A total of 258 patients were included in this study: TDF (n = 135) and ETV (n = 123). The prevalence of osteopenia was much higher in the TDF group at week 48 and week 96. The TDF group showed significant mean percentage decrease from baseline in bone mineral density throughout the treatment course. Logistic regression analysis adjusted for the propensity score demonstrated that the use of TDF was the only predictive factor of significant bone density loss at week 144. The mean percentage decline of estimated glomerular filtration rate was significant in the TDF group at all time points. Renal threshold phosphate concentration was similar among both treatment groups.

CONCLUSIONS

This study suggested CHB patients treated with TDF may experience increased risks of bone loss and renal deficits compared to those treated with ETV.

Brief Report: Subclinical Kidney Dysfunction in HIV-Infected Children: A Cross-Sectional Study

OBJECTIVE

Most of the kidney dysfunction in HIV-positive children receiving antiretroviral therapy (ART) is attributed to tenofovir. There is a paucity of data on kidney dysfunction in tenofovir-naive children. The primary objective was to know the point prevalence of albuminuria and β2-microglobulinuria in HIV-infected children aged 3-18 years receiving ART. Albuminuria and β2-microglobulinuria were used as surrogates for glomerular and tubular dysfunction, respectively. The secondary objective was to determine their predictors.

DESIGN

Cross-sectional study-design.

METHODS

One hundred consecutive HIV-positive children (3-18 years) on ART were included. Spot urine sample was analyzed for urinary creatinine, total protein, microalbumin, and β2-microglobulin. Albuminuria was defined as albumin to creatinine ratio of >30 mg/g; proteinuria as urine dipstick ≥trace or spot urine protein to creatinine ratio (uPCR) of ≥0.2. β2-microglobulinuria was defined as β2-microglobulin levels of >350 µg/L.

RESULTS

There were 71 boys and 29 girls. Most of the children had WHO clinical stage I and were getting zidovudine-based regimen. Only 7 children were getting tenofovir. estimated Glomerular Filtration Rate and serum creatinine were normal in all children. Approximately half (48%) had renal dysfunction in the form of glomerular dysfunction (26%), tubular dysfunction (27%), or both (5%). Age at diagnosis was significantly associated with β2-microglobulinuria (P = 0.044). None of the selected variables were associated with albuminuria.

CONCLUSIONS

HIV-associated glomerular and tubular dysfunction is common in children receiving ART other than tenofovir. The standard guidelines should consider including routine urinary biomarker monitoring in children on ART.

Calcaneal Quantitative Ultrasonography and Urinary Retinol-Binding Protein in Antiretroviral-Treated Patients With Human Immunodeficiency Virus in Uganda: A Pilot Study

BACKGROUND

Data on bone health and renal impairment in people with human immunodeficiency virus (HIV) in resource-limited settings are limited. The primary aim of this study was to investigate the potential role of calcaneal quantitative ultrasonography (QUS) in predicting bone mineral density (BMD) reduction in a population of Ugandan HIV-infected  individuals receiving long-term antiretroviral therapy; the secondary end point was to assess the prevalence of proximal tubular dysfunction and the correlation between elevated urinary retinol-binding protein-urinary creatinine ratio (uRBP/uCr) and reduced BMD.

METHODS

We conducted a cross-sectional study at the Infectious Diseases Institute, Kampala, Uganda. We included 101 HIV-infected adults who had been receiving continuous antiretroviral therapy for ≥10 years and had undergone dual-energy x-ray absorptiometry (DXA) during the previous 12 months. All patients underwent calcaneal QUS evaluation and urine sample collection.

RESULTS

DXA BMD measurements were significantly associated (P < .01) with calcaneal speed of sound, broadband ultrasound attenuation, and QUS index. Forty-seven individuals (47%) had abnormal uRBP/uCr values. A significant inverse correlation was observed between uRBP/uCr and DXA T scores (lumbar [P = .03], femoral neck [P < .001], and total hip [P = .002]).

CONCLUSIONS

Calcaneal QUS results showed a moderate correlation with DXA outputs. The identified high prevalence of subclinical tubular impairment also highlights the importance of expanding access to tenofovir disoproxil fumarate-sparing regimens in resource-limited settings.

Low bone mass in people living with HIV on long-term anti-retroviral therapy: A single center study in Uganda

BACKGROUND

This study set out to determine the prevalence of low bone mass following long-term exposure to antiretroviral therapy in Ugandan people living with HIV.

METHODS

A cross-sectional study was conducted among 199 people living with HIV that had been on anti-retroviral therapy for at least 10 years. All participants had dual X-ray absorptiometry to determine their bone mineral density. The data collected included antiretroviral drug history and behavioral risk data Descriptive statistics were used to summarize the data. Inferential statistics were analyzed using multilevel binomial longitudinal Markov chain Monte Carlo mixed multivariate regression modelling using the rstanarm package.

RESULTS

One hundred ninety nine adults were enrolled with equal representation of males and females. The mean age was 39.5 (SD 8.5) years. Mean durations on anti-retroviral treatment was 12.1 (SD 1.44) years, CD4 cell count was 563.9 cells/mm3. 178 (89.5%) had viral suppression with <50 viral copies/ml. There were 4 (2.0%) and 36 (18%) participants with low bone mass of the hip and lumbar spine respectively. Each unit increase in body mass index was associated with a significant reduction in the odds for low bone mineral density of the hip and lumbar spine. The duration on and exposure to the various antiretroviral medications had no significant effect on the participant's odds for developing low bone mass. All the coefficients of the variables in a multivariable model for either hip or lumbar spine bone mass were not significant.

CONCLUSION

These results provide additional evidence that patients on long term ART achieve bone mass stabilization. Maintaining adequate body weight is important in maintaining good bone health in people on antiretroviral therapy.

Comparison of viral control between two tenofovir dose reduction regimens (300 mg every 48 hours versus 300 mg every 72 hours) in chronic hepatitis B patients with moderate renal impairment from tenofovir-induced renal dysfunction

Long-term use of tenofovir disoproxil fumarate (TDF) can induce renal dysfunction that requires TDF dose reduction. Previous studies showed that systemic drug use exerts a threefold higher risk of moderate renal impairment. This study aimed to compare viral control between two tenofovir dose reduction regimens in chronic hepatitis B (CHB) patients with moderate renal impairment from TDF-induced renal dysfunction. This noninferiority, randomized controlled study was conducted at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. Virologically suppressed CHB patients treated with TDF who had moderate renal impairment were randomly allocated to receive TDF 300 mg either every 48 or 72 hours. Forty-six patients (67.4% male) with a mean age of 62.8 ± 7.8 years were enrolled. Among all patients, 34.8% were HBeAg-positive, and 23.9% had cirrhosis. All included patients completed 12 months of follow-up. No patients had virological breakthrough. After dose reduction, estimated glomerular filtration rate (eGFR) was improved in both groups, but a higher proportion of patients had an eGFR > 60 mL/min/1.73 m² in the TDF every 72 hours group. Other renal parameters, including serum phosphate, tubular maximal reabsorption for phosphate per GFR, urine protein-to-creatinine ratio, urine sugar and urine neutrophil gelatinase-associated lipocalin, were not significantly different between groups. Among TDF-treated CHB patients with TDF-induced moderate renal impairment, more aggressive dose reduction in TDF from every 48 hours to every 72 hours did not affect virological breakthrough. A higher proportion of patients in the TDF every 72 hours group had improvement in renal function.

Subclinical proximal tubulopathy in hepatitis B: The roles of nucleot(s)ide analogue treatment and the hepatitis B virus

BACKGROUND

The recommended monitoring tools for evaluating nucleot(s)ide analogue renal toxicity, such as estimated glomerular filtration rate (eGFR) and phosphatemia, are late markers of proximal tubulopathy. Multiple early markers are available, but no consensus exists on their use.

AIM

To determine the 24 mo prevalence of subclinical proximal tubulopathy (SPT), as defined with early biomarkers, in treated vs untreated hepatitis B virus (HBV)-monoinfected patients.

METHODS

A prospective, non-randomized, multicenter study of HBV-monoinfected patients with a low number of renal comorbidities was conducted. The patients were separated into three groups: Naïve, starting entecavir (ETV) treatment, or starting tenofovir disoproxil (TDF) treatment. Data on the early markers of SPT, the eGFR and phosphatemia, were collected quarterly. SPT was defined as a maximal tubular reabsorption of phosphate/eGFR below 0.8 mmoL/L and/or uric acid fractional excretion above 10%. The prevalence and cumulative incidence of SPT at month 24 (M24) were calculated. Quantitative data were analyzed using analyses of variance or Kruskal-Wallis tests, whereas chi-squared or Fisher’s exact tests were used to analyze qualitative data. Multivariate analyses were used to adjust for any potential confounding factors.

RESULTS

Of the 196 patients analyzed, 138 (84 naïve, 28 starting ETV, and 26 starting TDF) had no SPT at inclusion. At M24, the prevalence of SPT was not statistically different between naïve and either treated group (21.1% vs 30.7%, P < 0.42 and 50.0% vs 30.7%, P = 0.32 for ETV and TDF, respectively); no patient had an eGFR lower than 50 mL/min/1.73 m² or phosphatemia less than 0.48 mmoL/L. In the multivariate analysis, no explanatory variables were identified after adjustment. The cumulative incidence of SPT over 24 mo (25.5%, 13.3%, and 52.9% in the naïve, ETV, and TDF groups, respectively) tended to be higher in the TDF group vs the naïve group (hazard ratio: 2.283, P = 0.05). SPT-free survival at M24 was 57.6%, 68.8%, and 23.5% for the naïve, ETV, and TDF groups, respectively. The median survival time without SPT, evaluated only in the TDF group, was 5.9 mo.

CONCLUSION

The prevalence and incidence of SPT was higher in TDF-treated patients compared to naïve patients. SPT in the naïve population suggests that HBV can induce renal tubular toxicity.

Application of High-Performance Liquid Chromatography for Simultaneous Determination of Tenofovir and Creatinine in Human Urine and Plasma Samples

Tenofovir disoproxil fumarate is widely used in the therapy of human immunodeficiency virus and hepatitis B virus; however, a high concentration of the prodrug effects kidney function damage. To control the effectiveness of kidney functions in treated patients, the level of creatinine in the body must be controlled. This work describes a simple, fast, and “plastic-waste” reducing method for the simultaneous determination of tenofovir and creatinine in human urine and plasma. In both assays, only 50 µL of body fluid was required. The tests were carried out by reversed phase high-performance liquid chromatography with UV detection. In urine samples, the limits of detection for tenofovir and creatinine were 4 µg mL⁻¹ and 0.03 µmol mL⁻¹, respectively. In plasma samples, the limits of detection were 0.15 µg mL⁻¹ for tenofovir and 0.0003 µmol mL⁻¹ for creatinine. The method was applied for the determination of tenofovir and creatinine in human urine and plasma samples. The biggest advantage of the elaborated method is the possibility to determine tenofovir and creatinine in one analytical run in both urine and plasma sample collected from HIV and HBV patients. The possibility to reduce the level of laboratory waste in a sample preparation protocol is in the mainstream of a new trend of analytical chemistry which is based on green chemistry.

Prevalence of tubulopathy and association with renal function loss in HIV-infected patients

BACKGROUND

The incidence of chronic kidney disease (CKD) is 10 times higher in human immunodeficiency virus (HIV)-infected patients than in the general population. We explored the prevalence and determinants of proximal tubular dysfunction (PTD) in HIV-infected individuals, and assessed the impact of the tubulopathy on the estimated glomerular filtration rate (eGFR) outcome.

METHODS

A cohort study was performed on 694 outpatients followed in a French centre to analyse the prevalence of PTD, the diagnosis performance of screening tools and the associated factors. eGFR was prospectively evaluated to analyse the predictive value of the tubulopathy on eGFR decrease.

RESULTS

At inclusion, 14% of the patients presented with PTD and 5% with CKD. No individual tubular marker, including non-glomerular proteinuria, glycosuria dipstick or hypophosphataemia, registered sufficient performance to identify PTD. We found a significant interaction between tenofovir disoproxil fumarate exposure and ethnicity (P = 0.03) for tubulopathy risk. Tenofovir disoproxil fumarate exposure was associated with PTD in non-Africans [adjusted odds ratio (aOR) = 4.71, P < 10-3], but not in patients of sub-Saharan African origin (aOR = 1.17, P = 0.73). Among the 601 patients followed during a median of 4.3 years, 13% experienced an accelerated eGFR decline. Unlike microalbuminuria and glomerular proteinuria, tubulopathy was not associated with accelerated eGFR decline.

CONCLUSION

PTD is not rare in HIV-infected individuals but is less frequent in sub-Saharan African patients and is associated with tenofovir disoproxil fumarate exposure only in non-Africans. Its diagnosis requires multiple biochemical testing and it is not associated with an accelerated eGFR decline.

The utility of kidney injury molecule-1 as an early biomarker of kidney injury in people living with HIV

There are increasing reports of antiretroviral therapy (ART) drug-related kidney dysfunction. Traditional markers of kidney dysfunction such as urine protein/creatinine ratio and estimated glomerular filtration rate (eGFR) have thus far proven ineffective at detecting some sub-clinical forms of ART-related kidney injury. This is a cross-sectional examination of 114 people living with HIV (PLWH), either naïve (N =104) or treatment experienced (N =10). Urinary kidney injury molecule-1 (KIM-1 ng/mg) thresholds were estimated using electrochemiluminescent assays from stored urine samples and normalised for urinary creatinine excretion (KIM-1/Cr). Correlation coefficients and predictors of kidney tubular injury were compared and derived for both adjusted and unadjusted urinary KIM-1/CR (ng/mg). In PLWH (both ART-naïve and treatment experienced) had a higher baseline unadjusted and adjusted median (≥3.7 ng/mg) and upper tertile (≥6.25 ng/mg) urinary KIM-1/Cr levels compared to either non-normal volunteers (0.39 ng/mg) or those with acute kidney injury in the general population (0.57 ng/mg). When upper tertile KIM-1/Cr (≥6.25 ng/mg) was utilised as a marker of kidney injury, eGFR (ml/min/1.73 m²), white Caucasian ethnicity, and protease inhibitor exposure were significantly associated with increased risk of kidney injury in multivariate analyses (odds ratio 0.91, confidence interval [CI] 0.68–0.98, P = 0.02; odds ratio 8.9, CI 1.6–48.6, p = 0.01; and odds ratio 0.05, CI 0.03–0.9, p =0.04, respectively). We found a significant degree of sub-clinical kidney injury (high unadjusted and adjusted KIM-1/Cr) in PLWH with normal kidney function (eGFR ≥60 ml/min/1.73 m²). We also found a higher baseline KIM-1/Cr (ng/mg) in our study cohort than reported both in normal volunteers and patients with kidney injury in the general population.

People living with HIV and fracture risk

PLHIV have an increased risk of osteoporosis and fractures when compared with people of the same age and sex. In this review, we address the epidemiology and the pathophysiology of bone disease and fractures in PLHIV. The assessment of fracture risk and fracture prevention in these subjects is also discussed. The spectrum of HIV-associated disease has changed dramatically since the introduction of potent antiretroviral drugs. Today, the survival of people living with HIV (PLHIV) is close to that of the general population. However, the longer life-span in PLHIV is accompanied by an increased prevalence of chronic diseases. Detrimental effects on bone health are well recognised, with an increased risk of osteoporosis and fractures, including vertebral fractures, compared to the general population. The causes of bone disease in PLHIV are not fully understood, but include HIV-specific risk factors such as use of antiretrovirals and the presence of chronic inflammation, as well as traditional risk factors for fracture. Current guidelines recommend the use of FRAX to assess fracture probability in PLHIV age ≥ 40 years and measurement of bone mineral density in those at increased fracture risk. Vitamin D deficiency, if present, should be treated. Bisphosphonates have been shown to increase bone density in PLHIV although fracture outcomes are not available.

The spectrum of electrolyte abnormalities in black African people living with human immunodeficiency virus and diabetes mellitus at Edendale Hospital, Pietermaritzburg, South Africa

Background

Serum electrolyte abnormalities in black African people living with human immunodeficiency virus (HIV) and diabetes mellitus (PLWH/DM) is unknown.

Objectives

The aim of this study was to analyse serum electrolytes (sodium, potassium, calcium and phosphate) and factors associated with electrolyte abnormalities in black African PLWH/DM versus HIV-uninfected patients with DM.

Methods

We conducted a retrospective case-control study in 96 black African PLWH/DM (cases) and 192 HIV-uninfected patients with DM (controls), who were visiting the Edendale Hospital DM clinic, from 01 January 2016 to 31 December 2016. Pearson’s correlation, multivariate linear and logistic regression analyses were utilised.

Results

Hypocalcaemia was the most frequent electrolyte abnormality in PLWH/DM and HIV-uninfected patients with DM (31.25% vs. 22.91%), followed by hyponatraemia (18.75% vs. 13.54%). Median (IQR) corrected serum calcium levels were significantly lower in PLWH/DM compared with HIV-uninfected patients with DM (2.24 [2.18–2.30] mmol/L vs. 2.29 [2.20–2.36] mmol/L; p = 0.001). For every per cent increase in glycated haemoglobin, the odds of hyponatraemia significantly increased in both PLWH/DM (odds ratio [OR]: 1.55; 95% confidence interval [CI]: 1.19 –2.02; p = 0.003) and HIV-uninfected patients with DM (OR: 1.26; 95% CI: 1.04 –1.54; p = 0.009).

Conclusion

Hypocalcaemia and hyponatraemia were the most frequent electrolyte abnormalities and occurred more frequently in PLWH/DM compared with HIV-uninfected patients with DM. People living with HIV and DM have significantly lower corrected serum calcium levels compared with HIV-uninfected patients with DM. Furthermore, hyponatraemia is a marker of impaired glycaemic control.

Renal proximal tubulopathy in an HIV-infected patient treated with tenofovir alafenamide and gentamicin: a case report

Background

The nucleotide reverse transcriptase inhibitor Tenofovir Alafenamide (TAF) is a novel pro-drug of tenofovir (TFV) and possesses a superior renal safety profile compared with tenofovir disoproxil fumerate (TDF). Due to unique pharmacokinetic characteristics, treatment with TAF is not associated with significant renal proximal tubular accumulation of TFV. TAF is associated with a lower risk of acute kidney injury, chronic kidney disease, proteinuria and renal proximal tubular dysfunction than treatment with TDF. No cases of Fanconi syndrome have been reported in clinical trials of TAF. It is unknown whether treatment with TAF can lead to accumulation of TFV in proximal tubular cells and cause nephrotoxicity under certain clinical circumstances.

Case presentation

Here we report the case of a patient on stable TAF-based antiretroviral therapy with for HIV-1 infection who developed proximal tubulopathy when treated with gentamicin for febrile neutropenia in the context of relapsed Hodgkin lymphoma. Eighteen days after commencing chemotherapy for relapsed Hodgkin lymphoma the patient presented to hospital with fevers, hypotension and neutropenia. The patient was commenced on piperacillin, tazobactam and gentamicin. Within 24 h the patient developed marked hypokalaemia and hypophosphataemia requiring intravenous replacement therapy. There was proteinuria, glycosuria and evidence of marked urinary electrolyte wasting, consistent with acute proximal tubular dysfunction. Eleven days after the gentamicin was stopped the serum biochemistry normalised. The urinary electrolyte wasting and proteinuria had improved, and the glycosuria had resolved.

Conclusion

This is the first case report to describe acute renal proximal tubulopathy in an HIV-infected patient treated with TAF and gentamicin. As the number of patients prescribed TAF outside the clinical trial setting increases, so too does the potential for previously unreported drug interactions and adverse events. Clinicians need to be aware of potential unreported adverse drug reactions as the use of TAF becomes increasingly common in clinical practice.

Renal safety of tenofovir disoproxil fumarate and entecavir with hepatitis B immunoglobulin in liver transplant patients

Potent nucleos(t)ide analogues and hepatitis B immunoglobulin combinations are recommended after liver transplantation to prevent the recurrence of hepatitis B virus (HBV). Despite its proven efficacy, the renal safety of tenofovir disoproxil fumarate (TDF) has not been well established in liver transplant recipients. We aimed to assess the impacts of TDF and entecavir (ETV) on tubular and glomerular functions. We analysed 206 liver transplant patients treated with TDF (n = 102) or ETV (n = 104) plus hepatitis B immunoglobulin. Serum creatinine, phosphate and uric acid levels were measured. Proximal tubular dysfunction was defined as the presence of hypophosphatemia (<2 mg/dL) and hypouricemia (<2 mg/dL). Glomerular dysfunction was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m² accompanied by a ≥25% eGFR decline from baseline. During a median follow-up of 42.5 months, 48 patients developed proximal tubular dysfunction (30.4% and 16.3% in the TDF and ETV groups; P = .017). Serum levels of phosphate and uric acid were significantly lower in the TDF group post-LT. TDF (OR, 2.34; 95% CI, 1.16-4.69; P = .017) and low body mass index (OR, 2.11; 95% CI, 1.06-4.21; P = .034) were independent risk factors for proximal tubular dysfunction. The prevalence of glomerular dysfunction was not significantly different between the two groups (TDF 51.0% and ETV 54.8%; P = .582). TDF significantly increased the risk of proximal tubular dysfunction. Although the effect of TDF on glomerular function was comparable to that of ETV, glomerular dysfunction was common after liver transplant.

Estimated glomerular filtration rate slopes on tenofovir alafenamide

OBJECTIVES

The aim of the study was to analyse and compare estimated glomerular filtration rate (eGFR) slopes during exposure to tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) in individuals who initiated TAF, regardless of prior regimen, before October 2016.

METHODS

An observational cohort study was conducted at 11 clinics in the UK and Ireland. Mixed effects models with random intercept and time terms fitted were used to generate and compare eGFR slopes while participants were exposed to TDF and TAF, with adjustment for age, eGFR at TDF/TAF initiation, gender, ethnicity, and time-updated CD4 cell count and HIV RNA measurements.

RESULTS

Data were available for 357 subjects (median age 50 years; 80% male; 82% white/other ethnicity; 51% men who have sex with men; median nadir CD4 count 216 cells/µL). The median duration of exposure to TAF was 2.0 (interquartile range 1.6, 2.3) years. At TAF initiation, the median CD4 count was 557 cells/µL, the median eGFR was 80 mL/min/1.73 m², and 86% had suppressed HIV infection. The mean adjusted eGFR slope during TDF and TAF exposure was -2.08 [95% confidence interval (CI) -2.24, -1.92] and 1.18 (95% CI 0.20, 1.52) mL/min/1.73 m²/year, respectively (P < 0.001). Individuals who experienced rapid eGFR decline (> 3 or 5 mL/min/1.73 m²/year) while receiving TDF experienced significant eGFR recovery while on TAF (P < 0.001).

CONCLUSIONS

Significant improvement in eGFR slope was observed in patients who switched from TDF- to TAF-containing antiretroviral regimens. These data provide further support for the renal safety of TAF, and for switching those who experience progressive worsening of renal function from TDF to TAF.

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.

Proximal renal tubular function in HIV-infected children on tenofovir disoproxil fumarate for treatment of HIV infection at two tertiary hospitals in Harare, Zimbabwe

BACKGROUND

Renal abnormalities in HIV infected children may be due to the HIV infection or treatment among other factors. Tenofovir disoproxil fumarate (TDF) is associated with proximal renal tubular dysfunction, proteinuria and decrease in glomerular function. Studies in developed countries have shown variable prevalence of proximal renal tubular dysfunction in children on TDF. There are no known studies in developing countries, including Zimbabwe, documenting the proximal tubular function in HIV infected children on TDF. The aim of this study was to assess renal and proximal renal tubular function in HIV infected children receiving TDF and determine factors associated with proximal tubular dysfunction.

METHODS

A descriptive cross-sectional study was conducted in HIV infected patients below 18 years of age attending outpatient clinics at two tertiary hospitals in Harare, who received a TDF-containing antiretroviral regimen for at least six months. Dipstick protein and glucose, serum and urine phosphate and creatinine levels were measured. Fractional excretion of phosphate was calculated. Estimated glomerular filtration rate (eGFR) was calculated using the Schwartz formula. Tubular dysfunction was defined by at least two of the following characteristics: normoglycaemic glycosuria, hypophosphatemia and fractional excretion of phosphate > 18%.

FINDINGS

One hundred and ninety-eight children below 18 years of age were recruited over a period of six months. The prevalence of tubular dysfunction was 0.5%. Normoglycaemic glycosuria occurred in 1 (0.5%), fractional excretion of phosphate >18% in 4 (2%), and hypophosphatemia in 22 [11.1%] patients. Severe stunting was associated with increased risk of hypophosphatemia (OR 9.31 CI (1.18, 80.68) p = 0.03). Reduction in estimated glomerular filtration rate (eGFR) < 90ml/min/1.73m2 and proteinuria was evident in 35.9% and 32.8% of children, respectively. Concurrent TDF and HIV-1 protease inhibitor-based regimen was the only independent factor associated with reduction in GFR (OR 4.43 CI (1.32; 4.89) p = 0.016).

CONCLUSION

Tubular dysfunction was uncommon in Zimbabwean children on a TDF-based ART regimen. Hypophosphatemia, proteinuria and reduction in eGFR were common. Reassessing renal function using more sensitive biomarkers is needed to examine the long-term tolerance of TDF.

Prevalence of renal dysfunction among HIV infected patients receiving Tenofovir at Mulago: a cross-sectional study

BACKGROUND

There is an increasing burden of non-communicable disease globally. Tenofovir disoproxil fumarate (TDF) is the most commonly prescribed antiretroviral drug globally. Studies show that patients receiving TDF are more prone to renal dysfunction at some point in time during treatment. Evaluation of kidney function is not routinely done in most HIV public clinics. Identification of renal dysfunction is key in resource constrained settings because managing patients with end stage renal disease is costly.

METHOD

This was a cross-sectional study conducted at an outpatient clinic in 2018 involving patients on TDF for at least 6 months who were 18 years or older. Patients with documented kidney disease and pregnancy were excluded. Estimated glomerular filtration rate (eGFR) was calculated using the CKD-Epi formula. Renal dysfunction was defined as any of the following; either eGFR< 60 mL/min/1.73m2,or proteinuria of ≥2+ on urine dipstick, glycosuria with normal blood glucose. Electrolyte abnormalities were also documented.

RESULTS

We enrolled 278 participants. One hundred sixty nine (60.8%) were females, majority 234(84.2%) were < 50 years old, 205 (73.74%) were in WHO stage 1, most participants 271(97.5%) in addition to TDF were receiving lamivudine/efavirenz. The median age was 37(IQR 29-45) years; median duration on ART was 36 (IQR 24-60) months. The prevalence of renal dysfunction was 2.52% (7/278). Most noted electrolyte abnormality was hypocalcaemia (15.44%).

CONCLUSIONS

The prevalence of renal dysfunction was low though some participants had hypocalcaemia. Screening for kidney disease should be done in symptomatic HIV infected patients on TDF.

Nephrotoxicity of Antimicrobials and Antibiotics

Medication-induced nephrotoxicity remains one of the most common causes of acute kidney injury (AKI) among hospitalized patients. Within the extensive group of medications associated with AKI, antibiotics and other antimicrobials are well recognized triggers of structural and functional renal impairment. Clinical manifestations range from mild forms of tubular injury to significant deterioration of kidney function requiring acute renal replacement therapy. Several mechanisms are described, although the most frequent are acute interstitial nephritis, acute tubular necrosis, intratubular crystal deposition, and proximal/distal tubulopathy with electrolyte wasting abnormalities. General risk factors for antimicrobial-induced AKI include pre-existing chronic kidney disease, and concomitant use of medication with nephrotoxic potential. Prevention and early recognition of AKI represent the standard approach to mitigate AKI and avoid morbidity.

Risk of Nephrotoxicity in Patients With Drug-Resistant Tuberculosis Treated With Kanamycin/Capreomycin With or Without Concomitant Use of Tenofovir-Containing Antiretroviral Therapy

BACKGROUND

The intersection of HIV and drug-resistant (DR) tuberculosis (TB) presents the challenge of managing convergent drug toxicities.

METHODS

We conducted a retrospective study of adult patients with DR-TB treated with a kanamycin/capreomycin-based (KM) regimen, with or without concomitant antiretroviral therapy (ART). We estimated the incidence of nephrotoxicity (defined as an increase in serum creatinine greater than 26.5 µmol, or an increase in serum creatinine to 1.5 times the baseline value, or a decline in glomerular filtration rate to less than 60 mL/min/1.73 m), and evaluated the association between reported drug use and nephrotoxicity using Kaplan-Meier plots.

RESULTS

A total of 215 patients with DR-TB were treated with a kanamycin/capreomycin-based regimen, with or without concomitant ART. The incidence rate of nephrotoxicity was 3.6 [95% confidence interval (CI): 1.4 to 7.3], 6.9 (95% CI: 5.2 to 9.0), and 12 (95% CI: 3.3 to 30.9) cases per 100 person-months of follow-up in the KM only group (n = 42), the KM + TDF (tenofovir disoproxil fumarate) group (n = 163), and the KM + Other ART group (n = 10), respectively. Using the KM only group as a reference, the hazard ratio was 2.06 (95% CI: 0.92 to 4.63) in the KM + TDF group, and 4.09 (95% CI: 1.17 to 14.25) in the KM + Other ART group. Advancing age was an independent predictor of nephrotoxicity (adjusted hazard ratio 1.29, 95% CI: 1.14 to 1.46).

CONCLUSIONS

Our findings provide evidence of a significant risk of nephrotoxicity during treatment with a kanamycin/capreomycin-based DR-TB regimen, with or without concurrent treatment with ART. This study lends further support to calls for the substitution of TDF during the intensive phase of DR-TB treatment and for close monitoring of renal function during DR-TB treatment, especially in settings where the use of kanamycin/capreomycin is unavoidable.

Reliability of calcium-phosphorus (Ca/P) ratio as a new, accurate and inexpensive tool in the diagnosis of some Ca-P disorders

PURPOSE

The serum calcium/phosphorus (Ca/P) ratio is an accurate tool to differentiate patients with primary hyperparathyroidism (PHPT) from healthy subjects. However, other disorders of the Ca-P metabolism might impair the Ca/P ratio, such as hypophosphatemia (HypoP) not PHPT related. The aim of this study is to examine the diagnostic value of Ca/P ratio in the diagnosis of PHPT and HypoP not PHPT related.

METHODS

Single-center, retrospective, case-control study, including 150 patients with PHPT and 306 patients with HypoP, compared with 150 controls. HypoP patients were enrolled among HIV-infected patients by selecting those with Fanconi-like syndrome due to antiretroviral treatment. Parameters which were measured were serum Ca, P, parathyroid hormone (PTH), 25-OH vitamin D, albumin and creatinine).

RESULTS

The Ca/P ratio was significantly higher in PHPT and HypoP patients, compared to controls (p < 0.0001). At receiver operator characteristic (ROC) curve analysis, the cut-off of 3.56 (2.75 SI) for Ca/P ratio was able to identify patients with PHPT and HypoP (sensitivity 95%; specificity 93%). Among patients with Ca/P ratio above 3.56, the thresholds of 10.3 mg/dL (2.6 mmol/L) for serum Ca (sensitivity 93%; specificity 98%) and 80.5 pg/mL for PTH (sensitivity 91%; specificity 91%) were defined for the specific diagnosis of PHPT.

CONCLUSIONS

The Ca/P ratio above 3.56 (2.75 SI) is a highly accurate tool to identify PHPT and HypoP not PHPT-related patients. Thanks to its simplicity, this index can be proposed as a screening and first-line examination in the diagnostic work-up when a disorder of Ca-P metabolism is suspected or should be ruled out.

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.

Tenofovir Has Minimal Effect on Biomarkers of Bone Health in Youth with HIV Receiving Initial Antiretroviral Therapy

Both HIV infection and tenofovir disoproxil fumarate (TDF) treatment adversely impact bone metabolism and may lead to osteopenia, which has critical implications for youth with HIV (YWH). This study evaluates changes in the biomarkers of bone metabolism and inflammation among YWH receiving initial treatment with TDF- and non-TDF-containing antiretroviral therapies (ARTs). YWH [n = 23, median age 21 years (range 18-24), 87% male, 61% African American] were assessed for inflammatory and bone metabolism biomarkers at enrollment, after 48 weeks of TDF-containing ART, and 96 weeks of ART without TDF with continued viral suppression. Spearman's rank correlation evaluated biomarker associations. Bone alkaline phosphatase, parathyroid hormone, and osteopontin increased after TDF treatment. All fell after TDF was discontinued. Levels of RANKL and osteoprotegerin did not change throughout the study. There was little correlation between biomarkers of bone metabolism and either macrophage or lymphocyte activation at any time point. Our results establish baseline associations between bone metabolism and immune biomarkers for this population, and find that before CD4 T cell decline chronic inflammation does not perturb biomarkers of bone metabolism among YWH. The adverse effects of TDF on bone health may be marginal for YWH at the early stages of disease.

Prevalence of Nephrotoxicity in HIV Patients Treated with Tenofovir Disoproxil Fumarate: A Single-center Observational Study

Objectives

Tenofovir disoproxil fumarate (TDF) has been reported to cause nephrotoxicity necessitating cessation in some patients. No information is available on the nephrotoxic effect of TDF in Omani or regional patients with HIV infection. We sought to determine the prevalence of the nephrotoxic effects of TDF in our cohort of Omani patients with HIV and investigate the nephrotoxic effects of other cofactors.

Methods

We conducted an observational cohort study on 83 Omani patients currently on TDF-containing antiretroviral therapy. Renal dysfunction was monitored by measuring the serum creatinine estimated glomerular function rate (eGFR), urinary protein creatinine ratio (uPCR), and fractional excretion of phosphate (FEPi). Fisher's exact test was used to determine any additional nephrotoxic effects of cofactors.

Results

The median values for the duration of TDF use, patient age, and body mass index (BMI) at the time of the study were 178 weeks (range = 3-554), 42 years (range = 21-80), and 27 (range = 17.4-42.7), respectively. The median initial CD4 count and viral load were 205 × 10⁶/L (range = 3-1745) and 37 250 copies/mL (range = undetectable-9 523 428), respectively. FEPi was high in two (2.4%) patients, moderate in 26 (31.3%), and low in 55 (66.3%) patients. uPCR was high in 10 (12.0%) patients, moderate in 28 (33.7%), and low in 45 (54.2%) patients. No cofactors added to the nephrotoxicity except hypertension (p = 0.045).

Conclusions

Better definitions for TDF-associated toxicity are needed. uPCR is not a very good indicator of TDF-associated tubular dysfunction. Omani patients with HIV on TDF have a 4% prevalence of renal toxicity, but a study with a larger number of patients is required to explore this observation further. Cofactors like duration of TDF use, age, BMI, gender, diabetes mellitus, and use of protease inhibitors did not have an impact on the severity of FEPi and uPCR.

Pre-exposure Prophylaxis With Tenofovir Disoproxil Fumarate/Emtricitabine and Kidney Tubular Dysfunction in HIV-Uninfected Individuals

BACKGROUND

Pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is becoming increasingly adopted for HIV prevention. Tenofovir can cause proximal tubular damage and chronic kidney disease in HIV-infected persons, but little is known regarding its nephrotoxic potential among HIV-uninfected persons. In this study, we evaluated the effects of PrEP on urine levels of the following: α1-microglobulin (α1m), a marker of impaired tubular reabsorption; albuminuria, a measure of glomerular injury; and total proteinuria.

SETTING

The Iniciativa Profilaxis Pre-Exposicion (iPrEx) study randomized HIV-seronegative men and transgender women who have sex with men to oral TDF/FTC or placebo. The iPrEx open-label extension (iPrEx-OLE) study enrolled former PrEP trial participants to receive open-label TDF/FTC.

METHODS

A cross-sectional analysis compared urine biomarker levels by study arm in iPrEx (N = 100 treatment arm, N = 100 placebo arm). Then, urine biomarker levels were compared before and after PrEP initiation in 109 participants of iPrEx-OLE.

RESULTS

In iPrEx, there were no significant differences in urine α1m, albuminuria, or proteinuria by treatment arm. In iPrEx-OLE, after 24 weeks on PrEP, urine α1m and proteinuria increased by 21% [95% confidence interval (CI): 10 to 33] and 18% (95% CI: 8 to 28), respectively. The prevalence of detectable α1m increased from 44% to 65% (P < 0.001) and estimated glomerular filtration rate declined by 4 mL/min/1.73 m (P < 0.001). There was no significant change in albuminuria (6%; 95% CI: -7% to 20%).

CONCLUSION

PrEP with TDF/FTC was associated with a statistically significant rise in urine α1m and proteinuria after 6 months, suggesting that PrEP may result in subclinical tubule dysfunction.

Tenofovir disoproxil fumarate initiation and changes in urinary biomarker concentrations among HIV-infected men and women

OBJECTIVES

Urinary biomarkers of kidney injury may have potential to identify subclinical injury attributable to tenofovir disoproxil fumarate (TDF) toxicity.

DESIGN

This observational study included 198 HIV-infected participants from the Multicenter AIDS Cohort Study and the Women's Interagency HIV Study, who initiated TDF between 2009 and 2015 and had urine samples collected at baseline before and after TDF initiation.

METHODS

We used linear mixed-effects models controlling for urine creatinine and time on TDF to evaluate the effects of TDF initiation on changes in 14 urinary biomarkers.

RESULTS

Within 1 year after TDF initiation, concentrations of trefoil factor 3 [+78%; 95% confidence interval (CI) +38%, +129%), alpha-1 microglobulin (α1m) (+32%; 95% CI +13%, +55%), clusterin (+21%; 95% CI +6%, +38%), uromodulin (+19%; 95% CI +4%, +36%), and kidney injury molecule-1 (KIM-1) (+13%; 95% CI +1%, +26%) significantly increased, whereas interleukin-18 (IL-18) significantly decreased (-13%, 95% CI -7%, -25%). Subsequent to the first year of TDF use, biomarker concentrations stabilized, and these changes were not statistically significant. When stratifying by baseline viremia (HIV-1 RNA < vs. ≥80 copies/ml), concentration changes for most biomarkers during the first year of TDF use were greater among aviremic vs. viremic participants, with significant differences in α1m (+80 vs. +22%), KIM-1 (+43 vs. +10%), beta-2 microglobulin (+83 vs. -10%), YKL-40 (+33 vs. -5%), and IL-18 (+20 vs. -27%).

CONCLUSIONS

TDF initiation was associated with substantial changes in urinary biomarkers of kidney injury within the first year of use, particularly among aviremic participants. A urinary biomarker panel may be a clinically useful tool to detect and monitor the heterogeneous effects of TDF on the kidney.

Clinical Pharmacology in HIV Therapy

The success of combination antiretroviral therapy in the treatment of HIV-1-positive individuals has shifted clinical attention toward combination antiretroviral drug regimens that optimize tolerability, long-term safety, and durable efficacy. Wherever patients have access to treatment, morbidity and mortality are increasingly driven by non-HIV-associated comorbidities, which may be observed earlier than in age-matched controls and despite the best available combination antiretroviral therapy. Similarly, HIV-1-positive individuals are now diagnosed and treated earlier with anticipated lifelong therapy. The contribution of specific antiretroviral agents to long-term morbidity and mortality is dependent on the pharmacologic characteristics of these agents, and it is increasingly important in this context.

The Hidden Burden of Fractures in People Living With HIV

The survival of people living with human immunodeficiency virus (HIV) has increased markedly since the advent of antiretroviral therapy (ART). However, other morbidities have emerged, including osteoporosis. The estimated incidence of fractures at any site in people living with HIV ranges from 0.1 per 1000 person‐years to 8.4 per 1000 person‐years: at least twice that of people without HIV. This increased risk seems to be related to HIV itself and its treatment. Risk factors for bone disease in HIV‐positive (HIV⁺) subjects include both classical risk factors for osteoporosis and fracture and factors linked to HIV itself, such as inflammation, reconstitution syndrome, low CD4, ART, and co‐infection with hepatitis B and C viruses. The risk of fractures in these individuals can be at least partially assessed by measurement of BMD and the Fracture Risk Assessment Tool (FRAX™). Only alendronate and zoledronic acid have been studied in HIV⁺ individuals; both show beneficial effects on BMD, although data on fracture reduction are not available. © 2018 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Management of drug-resistant tuberculosis in special sub-populations including those with HIV co-infection, pregnancy, diabetes, organ-specific dysfunction, and in the critically ill

Tuberculosis remains a major problem globally, and is the leading cause of death from an infectious agent. Drug-resistant tuberculosis threatens to marginalise the substantial gains that have recently been made in the fight against tuberculosis. Drug-resistant TB has significant associated morbidity and a high mortality, with only half of all multidrug-resistant TB patients achieving a successful treatment outcome. Patients with drug-resistant TB in resource-poor settings are now gaining access to newer and repurposed anti-tuberculosis drugs such as bedaquiline, delamanid and linezolid. However, with ever increasing rates of co-morbidity, there is little guidance on how to manage complex patients with drug-resistant TB. We address that knowledge gap, and outline principles underpinning the management of drug-resistant TB in special situations including HIV co-infection, pregnancy, renal disease, liver disease, diabetes, and in the critically ill.

Bone mineral density reductions after tenofovir disoproxil fumarate initiation and changes in phosphaturia: a secondary analysis of ACTG A5224s

Background

It is unknown if the greater reductions in bone mineral density (BMD) associated with initiation of tenofovir disoproxil fumarate compared with abacavir in previously untreated HIV-infected participants in the ACTG A5224s clinical trial were associated with potentially worsening tenofovir-related phosphaturia.

Methods

We correlated changes in BMD at the hip and spine with changes in phosphaturia [transtubular reabsorption of phosphorus (TRP) and tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR)] from entry through week 96 in those initiating tenofovir ( n  =   134) versus abacavir ( n  =   135) with efavirenz or atazanavir/ritonavir in A5224s. We also correlated changes in BMD with tenofovir AUC measured between weeks 4 and 24.

Results

Changes in TRP and TmP/GFR through week 96 between the tenofovir and abacavir arms were not significantly different (both P  ≥   0.70) and did not differ with use of efavirenz versus atazanavir/ritonavir. There were no significant correlations between changes in either TRP or TmP/GFR and with either hip or spine BMD in the tenofovir arms. Tenofovir AUC was significantly correlated with changes in hip BMD, but not spine BMD, at week 24 ( r  =   -0.22, P  =   0.028) and week 48 ( r  =   -0.26, P  =   0.010), but not at week 96 ( r  =   -0.14, P  =   0.18).

Conclusions

Changes in phosphaturia were not different between the tenofovir and abacavir arms in A5224s. Changes in hip and spine BMD with tenofovir were not related to changes in phosphaturia. However, tenofovir exposure was weakly associated with changes in hip BMD through week 48.

Renal health after long-term exposure to tenofovir disoproxil fumarate (TDF) in HIV/HBV positive adults in Ghana

OBJECTIVES

The study assessed markers of renal health in HIV/HBV co-infected patients receiving TDF-containing antiretroviral therapy in Ghana.

METHODS

Urinary protein-to-creatinine ratio (uPCR) and albumin-to-protein ratio (uAPR) were measured cross-sectionally after a median of four years of TDF. At this time, alongside extensive laboratory testing, patients underwent evaluation of liver stiffness and blood pressure. The estimated glomerular filtration rate (eGFR) was measured longitudinally before and during TDF therapy.

RESULTS

Among 101 participants (66% women, median age 44 years, median CD4 count 572 cells/mm³) 21% and 17% had detectable HIV-1 RNA and HBV DNA, respectively. Overall 35% showed hypertension, 6% diabetes, 7% liver stiffness indicative of cirrhosis, and 18% urinary excretion of Schistosoma antigen. Tubular proteinuria occurred in 16% of patients and was independently predicted by female gender and hypertension. The eGFR declined by median 1.8 ml/min/year during TDF exposure (IQR -4.4, -0.0); more pronounced declines (≥ 5 ml/min/year) occurred in 22% of patients and were associated with receiving ritonavir-boosted lopinavir rather than efavirenz. HBV DNA, HBeAg, transaminases, and liver stiffness were not predictive of renal function abnormalities.

CONCLUSIONS

The findings mandate improved diagnosis and management of hypertension and suggest targeted laboratory monitoring of patients receiving TDF alongside a booster in sub-Saharan Africa.