Renal impairment in a rural African antiretroviral programme

Prevalence of kidney injury in patients taking tenofovir based antiretroviral therapy at a primary health care clinic, in East Rand,Gauteng Province

Background: Tenofovir disoproxil fumarate (TDF) is currently one of the key medicines in the management of HIV-1 infection across the globe. Conversely, various studies indicate that TDF is associated with an increased risk of kidney injury. Furthermore, data from different studies indicate that clinically significant TDF-related kidney toxicity is uncommon, with an estimated incidence of reduction in creatinine clearance to below 50 ml/min ranging from 3% to 8%.Objective: This study investigated the prevalence of TDF-induced kidney injury, risk factors associated with the exacerbation of kidney injury, and reversibility of TDF-induced kidney injury in a South African cohort.Methods: A retrospective cross-sectional descriptive study was conducted, where quantitative data were collected through patient file reviews. Files of 600 patients initiated on TDF-based antiretroviral therapy (ART) were reviewed. The degree of kidney function was monitored using the eGFR at baseline, 3, 6, 12, and 36 months of TDF therapy. eGFR after TDF discontinuation was monitored to determine its reversibility. HIV parameters (CD4 count and viral load) were monitored to determine patients' immune response to treatment throughout the study. Comorbidities and other factors that affect kidney function were extracted from the patients' files.Results: Final sample comprised 413 files, 272 (65.9%) were females. Significant variability in the eGFR overtime was observed; 20 (5.9%) experienced mild-moderate kidney injury, four (1.2%) developed moderate-severe kidney injury and three (1%) had severe kidney injury. Significant association with decline in eGFR included high viral load, low CD4 count and long duration of treatment. Six (1.5%) patients were discontinued from TDF treatment and five patients of those fully recovered.Conclusions: TDF-induced kidney injury was uncommon in this setting and where it occurred was associated with full reversibility after discontinuation. Therefore, lack of resources in health-care settings in terms of frequent monitoring of renal function should not prevent prescribing TDF-based therapy.

The baseline glomerular filtration rate, predictive of six-year survival in sub-Saharan African patients on antiretroviral therapy for HIV: Cohort study

BACKGROUND

Recently, serious morbidity events associated with initial glomerular filtration rate (GFR) have been described during HIV infection, but this is insufficiently investigated in sub-Saharan Africa very affected by HIV.

OBJECTIVE

To assess the impact of baseline GFR prevailing during the first semester of the HIV infection management on six-year survival in peoples taking antiretroviral therapy.

PATIENTS AND METHODS

Closed retrospective cohort study. The death was the expected outcome, the baseline GFR (mL/min/1.73m²) in the first semester of the follow-up was the main exposure. Kaplan-Meier method, Cox regression were used for analysis.

RESULTS

According to baseline GFR: <60, 60-89 and≥90, the six-year survival was 81.6%; 95.8% and 96.4% (P=0.067 Breslow). Adjusted hazard ratio for baseline GFR<60 and 60-89 (vs. ≥90) were respectively 5.4 (95%CI: 1.4-19.9; P=0.012) and 1.2 (95%CI: 0.3-4.0; P=0.754). The etiological fraction of deaths attributable to baseline GFR: GFR<60: 81% (95%CI: 0.31-0.95), GFR=60-89: 18.0% (95%CI: -0.7-0.8). Prognostic concordance index=0.84 (95%CI: 0.59-0.95) for GFR<60 and 0.55 (95%CI: 0.27-0.81) for GFR 60-89.

DISCUSSION

The etiological fraction of death and prognostic concordance index associated to baseline GFR level increase significantly with decline of baseline GFR.

CONCLUSION

Baseline GFR seems to predict the six-year survival in African sub-Saharan patients treated for HIV.

Risk factors and co-morbidities associated with changes in renal function among antiretroviral treatment-naïve adults in South Africa: A chart review

INTRODUCTION

Our systematic scoping review has demonstrated a research gap in antiretroviral treatment (ART) nephrotoxicity as well as in the long-term outcomes of renal function for patients on ART in South Africa. Bearing in mind the high prevalence of human immunodeficiency virus (HIV) in South Africa, this is of great concern.

OBJECTIVES

To determine the risk factors and co-morbidities associated with changes in renal function in HIV-infected adults in South Africa.

METHODS

We conducted a retrospective study of 350 ART-naïve adult patients attending the King Edward VIII HIV clinic, Durban, South Africa. Data were collected at baseline (pre-ART) and at six, 12, 18 and 24 months on ART. Renal function was assessed in the 24-month period using the Modification of Diet in Renal Disease equation and was categorised into normal renal function (estimated glomerular filtration rate [eGFR] ≥ 60), moderate renal impairment (eGFR 30-59), severe renal impairment (eGFR 15-29) and kidney failure (eGFR < 15 mL/min/1.73 m2). Generalised linear models for binary data were used to model the probability of renal impairment over the five time periods, controlling for repeated measures within participants over time. Risk ratios and 95% confidence intervals (CI) were reported for each time point versus baseline.

RESULTS

The cohort was 64% female, and 99% were Black. The median age was 36 years. At baseline, 10 patients had hypertension (HPT), six had diabetes, 61 were co-infected with tuberculosis (TB) and 157 patients had a high body mass index (BMI) with 25.4% being categorised as overweight and 19.4% as obese. The majority of the patients (59.3%) were normotensive. At baseline, the majority of the patients (90.4%) had normal renal function (95% CI: 86% - 93%), 7.0% (CI: 5% - 10%) had moderate renal impairment, 1.3% (CI: 0% - 3%) had severe renal impairment and 1.3% (CI: 0% - 3%) had renal failure. As BMI increased by one unit, the risk of renal impairment increased by 1.06 (CI: 1.03-1.10) times. The association of HPT with abnormal renal function was found to be insignificant, p > 0.05. The vast majority of patients were initiated on tenofovir disoproxil fumarate (TDF) (90.6%), in combination with lamivudine (3TC) (100%) and either efavirenz (EFV) (56.6%) or nevirapine (NVP) (43.4%).

CONCLUSION

This study reports a low prevalence of baseline renal impairment in HIV-infected ART-naïve outpatients. An improvement in renal function after the commencement of ART has been demonstrated in this population. However, the long-term outcomes of patients with HIV-related renal disease are not known.

Renal manifestations of HIV during the antiretroviral era in South Africa: a systematic scoping review

BACKGROUND

It is estimated that 650,000 patients may develop human immunodeficiency virus (HIV)-related renal disease in South Africa. South Africa has recently adopted WHO policy, stipulating that all HIV-infected patients have access to antiretroviral treatment (ART) irrespective of CD4 cell count.

METHODS

We searched Google Scholar, PubMed, Medline, Cochrane Library, Worldcat.org and EBSCO host databases from July 2015 to December 2015. Eligibility criteria included articles pertaining to renal manifestations of HIV in South Africa from 2004 to 2015 in adult patients (≥ 18 years). We independently reviewed the articles for quality. Thematic content analysis was performed to identify patterns of renal manifestations from the included studies. The risk of bias (e.g. internal validity) in the included studies was evaluated using the mixed methods appraisal tool.

RESULTS

Eleven out 21 studies were eligible for data extraction. The prevalence of urine abnormalities on urine dipsticks was high but had poor sensitivity and specificity for detecting renal impairment. Normal renal function occurred in 28.4 to 79% of patients, mild renal impairment occurred in 19 to 57.1% and moderate renal impairment in 2 to 14.4%. Severe renal impairment occurred in 1.3% of patients. Both the Cockcroft-Gault equation (after correcting for bias) and the 4-variable Modification of Diet in Renal Disease equation (without the ethnicity factor for African Americans) have been validated for the estimation of glomerular filtration rate (eGFR) in Black South Africans. HIV-associated nephropathy was the most prevalent histology seen (57.2%). Older age, a lower CD4 count, a low haemoglobin and a detectable viral load were associated with renal impairment. Renal function improved in the first year of commencing ART as evidenced by the regression of proteinuria and the increase in eGFR.

CONCLUSION

The findings of the review have implications to the recently adopted 'test and treat' approach to HIV prevention and management.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016039270.

Is laboratory screening prior to antiretroviral treatment useful in Johannesburg, South Africa? Baseline findings of a clinical trial

BACKGROUND

Screening for renal, hepatic and haematological disorders complicates the initiation of current first-line antiretroviral therapy (ART). Each additional test done adds substantial costs, both through direct laboratory expenses, but also by increasing the burden on health workers and patients. Evaluating the prevalence of clinically relevant abnormalities in different population groups could guide decisions about what tests to recommend in national guidelines, or in local adaptations of these.

METHODS

As part of enrolment procedures in a clinical trial, 771 HIV-positive adults, predominantly from inner-city primary health care clinics, underwent laboratory screening prior to ART. Participants had to be eligible for ART, based on the then CD4 eligibility threshold of 350 cells/μL, antiretroviral naïve and have no symptoms of peripheral neuropathy.

RESULTS

Participants were mostly female (57%) and a mean 34 years old. Creatinine clearance rates were almost all above 50 mL/min (99%), although 5% had microalbuminuria. Hepatitis B antigenaemia was common (8% of participants), of whom 40% had a raised AST/ALT, though only 2 had transaminase levels above 200 IU/L. Only 2% of participants had severe anaemia (haemoglobin <8 g/dl) and 1% neutropaenia (neutrophils <0.75 × 10^9/L). Costs per case detected of hepatitis B infection was USD135, but more than USD800 for a raised creatinine.

CONCLUSIONS

Hepatitis B continues to be a common co-infection in HIV-infected adults, and adds complexity to management of ART switches involving tenofovir. Routine renal and haematological screening prior to ART detected few abnormalities. The use of these screening tests should be assessed among patients with higher CD4 counts, who may even have fewer abnormalities. Formal evaluation of cost-effectiveness of laboratory screening prior to ART is warranted.

The effect of Tenofovir on renal function among Ugandan adults on long-term antiretroviral therapy: a cross-sectional enrolment analysis

Background

WHO recommends using Tenofovir containing first line antiretroviral therapy (ART), however, Tenofovir has been reported to be associated with renal impairment and dysfunction. We compared renal function among individuals on Tenofovir and those on non-Tenofovir containing ART.

Methods

In a cross-sectional study of HIV-Positive adults on ART, at enrolment into a prospective cohort to study the long-term complications of ART in Uganda, information on biophysical measurements, medical history, clinical examination and renal function tests (RFTs) was collected. Fractional Tubular phosphate reabsorption and estimated glomerular filtration rate (eGFR) were calculated. Mean values of RFTs and proportions with abnormal RFTs were compared between non-Tenofovir containing (Non-TDF) and Tenofovir containing (TDF-ART) ART regimen groups using a general linear regression model. Durations of TDF exposure were also compared.

Results

Between July 2013 and October 2014, we enrolled 953 individuals on ART for 6 or more months, median duration on ART was 9.3 years, 385 (40.4 %) were on non-TDF and 568 (59.6 %) on TDF-ART regimens. The proportion of participants with Proteinuria (>30 mg/dl) was higher among the TDF-ART group than the non-TDF ART group. However, in multivariable analysis, there were no significant differences in the adjusted mean differences of eGFR, serum urea, serum creatinine, fractional tubular reabsorption of phosphate and serum phosphates when patients on TDF-ART were compared with those on non-TDF containing ART. There were no differences in renal function even when different durations on Tenofovir were compared.

Conclusions

We found no differences in renal function among patients on Tenofovir and non-Tenofovir containing ART for almost a decade. Tenofovir based first line ART can therefore safely be initiated even in settings without routine renal function monitoring.

Monitoring of kidney function in HIV-positive patients

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

Impaired renal function and associated risk factors in newly diagnosed HIV-infected adults in Gulu Hospital, Northern Uganda

Background

Screening for renal diseases should be performed at the time of diagnosis of human immunodeficiency virus (HIV) infection. Despite the high prevalence of HIV/AIDS in Northern Uganda, little is known about the status of renal function and its correlates in the newly diagnosed HIV-infected individuals in this resource limited region. We aimed to determine the status of renal function and factors associated with impaired renal function in newly diagnosed HIV-infected adults in Northern Uganda.

Methods

This was a seven month cross-sectional hospital-based study, involving newly diagnosed HIV-infected patients, 18 years and older. Patients with history of diabetes mellitus, hypertension and renal disease were excluded. Estimated glomerular filtration rate (eGFR) was calculated using Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula (Table one). Factors associated with impaired renal function (eGFR < 60 ml/min/1.73 m²) were thus sought.

Results

We enrolled 361 participants (230, 63.7% female) with Mean ± standard deviation age of 31.4 ± 9.5 years. 52, (14.4%) had impaired renal function (eGFR <60 mL/min/1.73 m²) and of this 37 (71.2%) moderate renal impairment (eGFR 30–59.9 mL/min/1.73 m²) while 15 (28.8%) had severe renal impairment (eGFR <30 mL/min/1.73 m²). Proteinuria was recorded in 189 (52.4%) participants. Of these, 154 (81.5%) had mild (1+) while 8 (4.2%) had severe (3+) proteinuria. Using logistic regression, age, CD4 cell count, and proteinuria were significantly associated with impaired renal function; age >34 years (OR 2.8, 95% CI 1.3 – 5.9; P =0.009), CD4 count <350 cells/μL (OR 2.4, 95% CI 1.0-4.7; P =0.039) and proteinuria (OR 9.6, 95% CI 5.2–17.9; P < 0.001).

Conclusion

The prevalence of impaired renal function was high in new HIV-infected individuals in this region with limited resources. So, screening for renal disease in HIV is recommended at the time of HIV diagnosis.

Renal impairment in HIV-infected patients initiating tenofovir-containing antiretroviral therapy regimens in a Primary Healthcare Setting in South Africa

OBJECTIVE

Long-term use of tenofovir disoproxil fumarate is associated with declines in glomerular function and chronic kidney disease in HIV-infected patients. We aimed to assess the prevalence and incidence of renal impairment in a primary care setting in sub-Saharan Africa.

METHODS

We analysed data from 1092 HIV-infected patients initiating tenofovir at a primary care clinic in Cape Town, South Africa. Renal function was assessed for the first 12 months on ART by estimating glomerular filtration rate (eGFR) calculated using the Cockroft-Gault equation categorised into normal, mild, moderate and severe reduction in renal function based on values >90, 60-89, 30-59 and <30 ml/min/1.73 m(2) , respectively. Associations were assessed using logistic regression, and average GFR trajectory over time was modelled using linear mixed-effects models.

RESULTS

The cohort consisted of 62% women; median age was 34 years (IQR 29; 41 years). The majority had normal renal function pre-ART (79%), 19% had mildly reduced GFR, and 2% had moderate renal impairment. Older age, more advanced WHO stage and anaemia were independently associated with prevalent renal impairment. On average, estimated glomerular function improved over the first year on tenofovir [1.10 ml/min/1.73 m(2) average increase over 12 months (95% CI: 0.80; 1.40)]. Male gender, anaemia and immunosuppression (WHO Stage III/IV and CD4 cell counts <100 cells/mm(3) ) were associated with lower average eGFR levels over time. Overall, 3% developed eGFR <50 ml/min/1.73 m(2) during this period. Serum creatinine tests conducted before 4 months on ART had low predictive value for predicting change in eGFR after a year on ART.

CONCLUSION

Generally, renal function improved in HIV-infected adults initiating ART in this primary healthcare setting during the first year on ART. While monitoring of renal function is recommended in the first 4 months on ART, renal impairment appears uncommon during the first 12 months of tenofovir-containing ART in primary care populations.

Baseline Renal Function among Antiretroviral Therapy-Naive, HIV-Infected Patients in Southeast Nigeria

Background:

Renal insufficiency has been shown to be a significant, independent risk factor for mortality among HIV-infected patients. Unfortunately, little is known about the prevalence and nature of renal impairment in African populations initiating antiretroviral treatment. This study aims to find the prevalence of abnormal renal function among antiretroviral therapy (ART)-naive, HIV-infected patients in the South Eastern geopolitical zone of Nigeria.

Method:

This is a cross-sectional hospital-based study, involving 300 ART-naive HIV-positive patients, seen over a 1-year period, aged from 18 years and older, presenting to the clinic for the first time.

Results:

A total of 300 patients were included in the study, 104 (34.7%) males and 196 (65.3%) females. The prevalence of significant renal disease was 24.3% (73 of 300), while 38.3% (115 of 300) had mild renal impairment. Using logistic regression, age, CD4 count, urea, creatinine, and hemoglobin were significantly associated with renal impairment.

Conclusion:

The authors observed a high prevalence of significant renal impairment among HIV-infected patients at the time of ART initiation.

Baseline Renal Function among Antiretroviral Therapy-Naive, HIV-Infected Patients in South East Nigeria

Background:Renal insufficiency has been shown to be a significant, independent risk factor for mortality among HIV-infected patients. Unfortunately, little is known about the prevalence and nature of renal impairment in African populations initiating antiretroviral treatment. This study aims to find the prevalence of abnormal renal function among antiretroviral therapy (ART)-naive, HIV-infected patients in the South Eastern geopolitical zone of Nigeria.Method:This is a cross-sectional hospital-based study, involving 300 ART-naive HIV-positive patients, seen over a 1-year period, aged from 18 years and older, presenting to the clinic for the first time.Results:A total of 300 patients were included in the study, 104 (34.7%) males and 196 (65.3%) females. The prevalence of significant renal disease was 24.3% (73 of 300), while 38.3% (115 of 300) had mild renal impairment. Using logistic regression, age, CD4 count, urea, creatinine, and hemoglobin were significantly associated with renal impairment.Conclusion:The authors observed a high prevalence of significant renal impairment among HIV-infected patients at the time of ART initiation.

Cystatin C-Based Evaluation of Kidney Function of HIV-Infected Children in Benin City, Southern Nigeria

Background. Human immunodeficiency virus (HIV) is now a confirmed risk factor for kidney disease with an increased burden in persons of African descent. Method. We measured the serum cystatin C levels of 205 ART-naive, HIV-infected children by an ELISA technique and compared them with the levels of apparently healthy children. Result. The mean ± SD serum cystatin C level of children with HIV infection was 1.01 ± 0.44 mg/L, significantly higher than the mean value in the control group, that is, 0.72 ± 0.20 mg/L (P = 0.000). The mean ± SD cystatin C-based estimated GFR of children with HIV infection was 102.7 ± 31.0 mL/min/1.73 m(2), significantly lower than 126.9 ± 28.5 mL/min/1.73 m(2) in the control group, (P = 0.014). A significantly higher proportion of HIV-infected children compared to controls had eGFR < 90 mL/min/1.73 m(2) (21.5% versus 5.4%; P = 0.00). The prevalence of chronic kidney disease (CKD) among the HIV-infected children was 10.7%. The cystatin C-based eGFR of the HIV-infected children ≥5 years old correlated positively with their CD4 count (r = 0.23;  P = 0.022). Conclusion. There is a high prevalence of CKD among HIV-infected children, requiring regular monitoring of their kidney function using a cystatin C-based method.

Relative risk of renal disease among people living with HIV: a systematic review and meta-analysis

Background

Antiretroviral therapy (ART) has substantially decreased mortality and HIV-related morbidity. However, other morbidities appear to be more common among PLHIV than in the general population. This study aimed to estimate the relative risk of renal disease among people living with HIV (PLHIV) compared to the HIV-uninfected population.

Methods

We conducted a systematic review and meta-analysis of relative risks of renal disease among populations of PLHIV reported in studies from the peer-reviewed literature. We searched Medline for relevant journal articles published before September 2010, yielding papers published during or after 2002. We also searched conference proceedings of the International AIDS Society (IAS) and Conference on Retroviruses and Opportunistic Infections (CROI) prior to and including 2010. Eligible studies were observational studies reporting renal disease defined as acute or chronic reduced renal function with glomerular filtration rate less than or equal to 60 ml/min/1.73 m² among HIV-positive adults. Pooled relative risks were calculated for various groupings, including class of ART drugs administered.

Results

The overall relative risk of renal disease was 3.87 (95% CI: 2.85-6.85) among HIV-infected people compared to HIV-uninfected people. The relative risk of renal disease among people with late-stage HIV infection (AIDS) was 3.32 (1.86-5.93) compared to other PLHIV. The relative risk of renal disease among PLHIV who were receiving antiretroviral therapy (ART) was 0.54 (0.29-0.99) compared to treatment-naïve PLHIV; the relative risk of renal disease among PLHIV who were treated with tenofovir was 1.56 (0.83-2.93) compared to PLHIV who were treated with non-tenofovir therapy. The risk of renal disease was also found to significantly increase with age.

Conclusion

PLHIV are at increased risk of renal disease, with greater risk at later stages of infection and at older ages. ART prolongs survival and decreases the risk of renal disease. However, less reduction in renal disease risk occurs for Tenofovir-containing ART than for other regimens.

The prevalence of renal impairment among adults with early HIV disease in Blantyre, Malawi

We determined the prevalence of renal impairment and possible HIV-associated nephropathy (HIVAN) in adults with World Health Organization (WHO) stages I or II HIV, presenting to the antiretroviral therapy (ART) clinic in a central hospital in Malawi. We enrolled 526 ART-naïve subjects, 67% women, median age 34 (17-73) years and mean CD4 count 305 (3-993) cells/μL. Blood pressure, weight, urine dipstick and microscopy, CD4 cell count and serum creatinine were measured. Creatinine clearance (CrCL) was estimated using the Cockcroft-Gault equation. Possible HIVAN was diagnosed based on levels of proteinuria and CrCl. In all, 23.3% had proteinuria (≥ 1+). 57.4% had reduced CrCl (< 90 mL/minute): 18.8% had moderate (CrCl 30-59 mL/minute) and 2.2% severe (CrCl <30 mL/minute) renal dysfunction. Extrapolating from renal biopsy studies that confirmed HIVAN, the proportion of patients with HIVAN in our clinic ranges from 1.8-21.2%. We conclude that renal impairment was common, though rarely severe, among HIV-infected adults with clinically non-advanced HIV disease. Renal dysfunction has been demonstrated to be a risk factor for (early) mortality. These results are relevant for ART programmes, such as those in Malawi, where renal function is not routinely assessed.

Relationship between renal dysfunction, nephrotoxicity and death among HIV adults on tenofovir

OBJECTIVE

In April 2010, the South African government added tenofovir disoproxil fumarate to its first-line antiretroviral therapy (ART) for HIV patients. We analyzed the relationship between renal dysfunction at tenofovir initiation, nephrotoxicity and mortality.

DESIGN

Cohort analysis of HIV-infected adults who received tenofovir and had a creatinine clearance done at initiation at the Themba Lethu Clinic, Johannesburg, South Africa, between April 2004 and September 2009.

METHODS

We estimated the relationship between renal dysfunction, nephrotoxicity [any decline in kidney function from baseline (acute or chronic) that is secondary to a toxin (including drugs)] and mortality for patients initiated onto tenofovir-containing regimens using marginal structural models and inverse probability of treatment weights to correct estimates for lost to follow-up and confounding.

RESULTS

Of 890 patients initiated onto tenofovir, 573 (64.4%) had normal renal function (≥90 ml/min), 271 (30.4%) had mild renal dysfunction (60-89 ml/min) and 46 (5.2%) had moderate renal dysfunction (30-59 ml/min). A total of 2.4% experienced nephrotoxicity, 7.8% died and 9.7% were lost during 48 months of follow-up. Patients with mild [hazard ratio 4.8; 95% confidence interval (CI) 1.5-15.2] or moderate (hazard ratio 15.0; 95% CI 3.4-66.5) renal dysfunction were at greatest risk of nephrotoxicity, whereas those with mild (hazard ratio 1.2; 95% CI 0.7-2.3) or moderate (hazard ratio 3.2; 95% CI 1.3-7.8) renal dysfunction vs. normal renal function were at highest risk of death by 48 months.

CONCLUSION

Much of the incident renal dysfunction in tenofovir patients is likely related to preexisting renal disorder, which may be exacerbated by tenofovir. With expanded use of tenofovir, screening for renal dysfunction prior to initiation and dose adjustment is necessary to help improve ART outcomes.

Association of age with mortality and virological and immunological response to antiretroviral therapy in rural South African adults

OBJECTIVE

To assess whether treatment outcomes vary with age for adults receiving antiretroviral therapy (ART) in a large rural HIV treatment cohort.

DESIGN

Retrospective cohort analysis using data from a public HIV Treatment & Care Programme.

METHODS

Adults initiating ART 1(st) August 2004-31(st) October 2009 were stratified by age at initiation: young adults (16-24 years) mid-age adults (25-49 years) and older (≥50 years) adults. Kaplan-Meier survival analysis was used to estimate mortality rates and age and person-time stratified Cox regression to determine factors associated with mortality. Changes in CD4 cell counts were quantified using a piecewise linear model based on follow-up CD4 cell counts measured at six-monthly time points.

RESULTS

8846 adults were included, 808 (9.1%) young adults; 7119 (80.5%) mid-age adults and 919 (10.4%) older adults, with 997 deaths over 14,778 person-years of follow-up. Adjusting for baseline characteristics, older adults had 32% excess mortality (p = 0.004) compared to those aged 25-49 years. Overall mortality rates (MR) per 100 person-years were 6.18 (95% CI 4.90-7.78); 6.55 (95% CI 6.11-7.02) and 8.69 (95% CI 7.34-10.28) for young, mid-age and older adults respectively. In the first year on ART, for older compared to both young and mid-aged adults, MR per 100 person-years were significantly higher; 0-3 months (MR: 27.1 vs 17.17 and 21.36) and 3-12 months (MR: 9.5 vs 4.02 and 6.02) respectively. CD4 count reconstitution was lower, despite better virological response in the older adults. There were no significant differences in MR after 1 year of ART. Baseline markers of advanced disease were independently associated with very early mortality (0-3 months) whilst immunological and virological responses were associated with mortality after 12 months.

CONCLUSIONS

Early ART initiation and improving clinical care of older adults are required to reduce high early mortality and enhance immunologic recovery, particularly in the initial phases of ART.

Tenofovir renal proximal tubular toxicity is regulated by OAT1 and MRP4 transporters

Tenofovir disoproxil fumarate (TDF) is an oral prodrug and acyclic nucleotide analog of adenosine monophosphate that inhibits HIV-1 (HIV) reverse transcriptase. A growing subset of TDF-treated HIV(+) individuals presented with acute renal failure, suggesting tenofovir-associated kidney-specific toxicity. Our previous studies using an HIV transgenic mouse model (TG) demonstrated specific changes in renal proximal tubular mitochondrial DNA (mtDNA) abundance. Nucleosides are regulated in biological systems via transport and metabolism in cellular compartments. In this study, the role(s) of organic anion transporter type 1 (OAT1) and multidrug-resistant protein type 4 (MRP4) in transport and regulation of tenofovir in proximal tubules were assessed. Renal toxicity was assessed in kidney tissues from OAT1 knockout (KO) or MRP4 KO compared with wild-type (WT, C57BL/6) mice following treatment with TDF (0.11 mg/day), didanosine (ddI, a related adenosine analog, 0.14 mg/day) or vehicle (0.1 M NaOH) daily gavage for 5 weeks. Laser-capture microdissection (LCM) was used to isolate renal proximal tubules for molecular analyses. mtDNA abundance and ultrastructural pathology were analyzed. mtDNA abundance in whole kidneys from both KO and WT was unchanged regardless of treatment. Renal proximal tubular mtDNA abundance from OAT1 KO also remained unchanged, suggesting prevention of TDF toxicity due to loss of tenofovir transport into proximal tubules. In contrast, renal proximal tubules from MRP4 KO exhibited increased mtDNA abundance following TDF treatment compared with WT littermates, suggesting compensation. Renal proximal tubules from TDF-treated WT and MRP4 KO exhibited increased numbers of irregular mitochondria with sparse, fragmented cristae compared with OAT1 KO. Treatment with ddI had a compensatory effect on mtDNA abundance in OAT1 KO but not in MRP4 KO. Both OAT1 and MRP4 have a direct role in transport and efflux of tenofovir, regulating levels of tenofovir in proximal tubules. Disruption of OAT1 activity prevents tenofovir toxicity but loss of MRP4 can lead to increased renal proximal tubular toxicity. These data help to explain mechanisms of human TDF renal toxicity.

Renal safety of a tenofovir-containing first line regimen: experience from an antiretroviral cohort in rural Lesotho

Introduction

Current guidelines contraindicate TDF use when creatinine clearance (CrCl) falls below 50 ml/min. We report prevalence of abnormal renal function at baseline and factors associated with abnormal renal function from a community cohort in Lesotho.

Methods

We calculated changes in CrCl from baseline for patients initiated on TDF at 6 and 12 months and the proportion of patients initiated on TDF who developed renal impairment. Screening algorithms were developed using risk factors determined by multivariate analysis.

Results

Among 933 adults for whom baseline creatinine was available, 176 (18.9%) presented with a baseline CrCl <50 ml/min. Renal function improved during follow-up. 19 patients who developed renal toxicity during follow up remained on TDF; renal function improved (CrCl≥50 ml/min) in all but 3 of these patients. Among 15 patients with a baseline CrCl <50 ml/min were started in error, none developed severe renal impairment.

Conclusion

In this setting TDF-associated renal toxicity is rare and mainly transient. Further studies to assess TDF safety at lower CrCl thresholds are warranted.

Changes in the renal function after tenofovir-containing antiretroviral therapy initiation in a Senegalese cohort (ANRS 1215)

To describe and compare the changes in renal function between HIV-1 infected adult patients receiving antiretroviral therapy (ART) with and without tenofovir (TDF). The population consisted of 40 patients starting a TDF-containing regimen and 388 patients starting regimen not containing TDF, and followed during 42 months. The estimated glomerular filtration rate (eGFR) was calculated using the Cockroft-Gault and MDRD equations and modeled separately for the first 12 months and the subsequent period. Between baseline and 12 months, the eGFR decreased significantly in patients receiving TDF (-10.40 ml/min), whereas it increased in the other +4.33 ml/min). A significant variability in the eGFR trajectories of patients receiving TDF was observed; 12 (30%) of them experienced a persistent decrease, 5 (12%) had an initial transient increase, and 23 (58%) a steady slow increase in eGFR. The characteristics at baseline of the patients with persistent decrease were not different from the other patients but their immune reconstitution was impaired. After 12 months, patients receiving TDF experienced a higher rate of transition from mild renal impairment (60-90 ml/min/1.73 m(2)) to moderate renal impairment (30-60 ml/min/1.73 m(2)) when compared with patients not receiving TDF. A significant though moderate decline in the renal function was observed in one-third of the patients receiving TDF compared to patients not receiving TDF. Moreover, this impairment was persistent after the first year of treatment.