Predictive performance of eGFR equations in South Africans of African and Indian ancestry compared with ⁹⁹mTc-DTPA imaging

Removal of ethnicity adjustment for creatinine-based estimated glomerular filtration rate equations

Creatinine-based estimated glomerular filtration rate equations (eGFRcreatinine) are used to measure excretory kidney function in clinical practice. Despite inter and intra-patient variability, eGFRcreatinine has excellent clinical utility and provides the basis for the classification system for chronic kidney disease (CKD), for kidney function monitoring, treatment interventions and referral pathways. The 4-variable modification of diet in renal disease (MDRD) eGFRcreatinine equation was introduced in 2000 and recommended by the National Institute for Health and Care Excellence (NICE) in 2008. Subsequently, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFRcreatinine equation was introduced in 2009 and is more accurate than MDRD in patients with mild and moderate CKD. In 2014, NICE recommended that CKD-EPI eGFRcreatinine replace MDRD eGFRcreatinine in routine clinical practice across England. Both equations originally incorporated adjustments for age, gender and ethnicity. However, the evidence for ethnicity adjustment has been increasingly questioned, and in 2021 NICE recommended that kidney function should be estimated by CKD-EPI eGFRcreatinine without using ethnicity adjustment. Recently, a CKD-EPI equation has been presented without ethnicity adjustment; however, this has not been validated outside of North America and NICE continues to recommend CKD-EPI 2009. We review the status of eGFRcreatinine in clinical practice, including the limitations of eGFRcreatinine and the rationale for removal of ethnicity adjustment and the potential impact of this change on clinical care for patients with kidney disease.

Comparison of CG, CKD-EPI[AS] and CKD-EPI[ASR] equations to estimate glomerular filtration rate and predict mortality in treatment naïve people living with HIV in Zimbabwe

BACKGROUND

Renal impairment in people living with HIV (PWH) in Sub-Saharan Africa is common and associated with increased morbidity and mortality. The ideal equation to estimate glomerular filtration rate (eGFR) in this population remains unclear. That which best predicts clinical risk may be the most appropriate while validation studies are awaited. Here we compare the Cockcroft-Gault (CG), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI[ASR]) and the CKD-EPI equation with the race coefficient removed (CKD-EPI[AS]), in a population of anti-retroviral therapy (ART) naïve PWH in Zimbabwe to assess which equation best predicts mortality.

METHODS

A retrospective cohort study of treatment naïve PWH at the Newlands Clinic in Harare, Zimbabwe was completed. The study included all patients commencing ART between 2007 and 2019. Predictors of mortality were assessed by multivariable logistic regression.

RESULTS

A total of 2991 patients were followed-up for a median of 4.6 years. The cohort was 62.1% female, with 26.1% of patients having at least one comorbidity. The CG equation identified 21.6% of patients as having renal impairment compared with 17.6% with CKD-EPI[AS] and 9.3% with CKD-EPI[ASR]. There was a mortality rate of 9.1% across the study period. The highest mortality risk was seen in those with renal impairment as determined by the CKD-EPI[ASR] equation for both eGFR < 90 and eGFR < 60 with OR 2.97 (95%CI 1.86-4.76) and OR 10.6 (95%CI 3.15-18.04) respectively.

CONCLUSION

In treatment naïve PWH in Zimbabwe, the CKD-EPI[ASR] equation identifies patients at highest risk of mortality when compared to the CKD-EPI[AS] and CG equations.

Use of Race in Kidney Function Estimation: Lessons Learned and the Path Toward Health Justice

In 2020, the nephrology community formally interrogated long-standing race-based clinical algorithms used in the field, including the kidney function estimation equations. A comprehensive understanding of the history of kidney function estimation and racial essentialism is necessary to understand underpinnings of the incorporation of a Black race coefficient into prior equations. We provide a review of this history, as well as the considerations used to develop race-free equations that are a guidepost for a more equity-oriented, scientifically rigorous future for kidney function estimation and other clinical algorithms and processes in which race may be embedded as a variable.

Limited Evidence for Use of a Black Race Modifier in eGFR Calculations: A Systematic Review

Background

Commonly used estimated glomerular filtration rate (eGFR) equations include a Black race modifier (BRM) that was incorporated during equation derivation. Race is a social construct, and a poorly characterized variable that is applied inconsistently in clinical settings. The BRM results in higher eGFR for any creatinine concentration, implying fundamental differences in creatinine production or excretion in Black individuals compared to other populations. Equations without inclusion of the BRM have the potential to detect kidney disease earlier in patients at the greatest risk of chronic kidney disease (CKD), but also has the potential to over-diagnose CKD or impact downstream clinical interventions. The purpose of this study was to use an evidence- based approach to systematically evaluate the literature relevant to the performance of the eGFR equations with and without the BRM and to examine the clinical impact of the use or removal.

Content

PubMed and Embase databases were searched for studies comparing measured GFR to eGFR in racially diverse adult populations using the Modification of Diet in Renal Disease or the 2009-Chronic Kidney Disease Epidemiology Collaboration-creatinine equations based on standardized creatinine measurements. Additionally, we searched for studies comparing clinical use of eGFR calculated with and without the BRM. 8,632 unique publications were identified; an additional 3 studies were added post-hoc. In total, 96 studies were subjected to further analysis and 44 studies were used to make a final assessment.

Summary

There is limited published evidence to support the use of a BRM in eGFR equations.

Development and Validation of Creatinine-Based Estimates of the Glomerular Filtration Rate Equation from 99mTc-DTPA Imaging in the Malaysian Setting

Introduction

Accurate assessment of glomerular filtration rate (GFR) is very important for diagnostic and therapeutic intervention. Clinically, GFR is estimated from plasma creatinine using equations such as Cockcroft-Gault, Modification of Diet in Renal Disease, and Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equations. However, these were developed in the Western population. To the best of our knowledge, there was no equation that has been developed specifically in our population.

Objectives

We developed a new equation based on the gold standard of ^99mTc-DTPA imaging measured GFR. We then performed an internal validation by comparing the bias, precision, and accuracy of the new equation and the other equations with the gold standard of ^99mTc-DTPA imaging measured GFR.

Methods

This was a cross-sectional study using the existing record of patients who were referred for ^99mTc-DTPA imaging at the Nuclear Medicine Centre, International Islamic University Malaysia. As this is a retrospective study utilising routinely collected data from the existing pool of data, the ethical committee has waived the need for informed consent.

Results

Data of 187 patients were analysed from January 2016 to March 2021. Of these, 94 were randomised to the development cohort and 93 to the validation cohort. A new equation of eGFR was determined as 16.637 ∗ 0.9935^Age ∗ (SCr/23.473)^-0.45159. In the validation cohort, both CKD-EPI and the new equation had the highest correlation to ^99mTc-DTPA with a correlation coefficient of 0.81 (p < 0.0001). However, the new equation had the least bias and was the most precise (mean bias of -3.58 ± 12.01) and accurate (P30 of 64.5% and P50 of 84.9%) compared to the other equations.

Conclusion

The new equation which was developed specifically using our local data population was the most accurate and precise, with less bias compared to the other equations. Further study validating this equation in the perioperative and intensive care patients is needed.

Estimated glomerular filtration rate equations in people of self-reported black ethnicity in the United Kingdom: Inappropriate adjustment for ethnicity may lead to reduced access to care

Assessment in African populations suggest adjustment for ethnicity in estimated glomerular filtration rate (eGFR) equations derived from African Americans lead to overestimation of GFR and failure to determine severity in chronic kidney disease (CKD). However, studies in African Europeans are limited. We aimed to assess accuracy of eGFR equations, with and without ethnicity adjustment compared with measured GFR in people of Black ethnicity in the United Kingdom. Performance of MDRD, CKD-EPI (with and without ethnicity adjustment), Full Age Spectrum (FAS), revised Lund Malmö (LM Revised), and European Kidney Function Consortium (EKFC) eGFR equations were assessed compared to 51Cr-EDTA GFR studies extracted from hospital databases. Participants with albumin <30g/l, liver disease, <18 years, of non-Black or non-White self-reported ethnicity were excluded. Agreement was assessed by bias, precision and 30%-accuracy and was stratified for ethnicity and GFR. 1888 51Cr-EDTA studies were included (Mean age-53.7yrs; 43.6% female; 14.1% Black ethnicity). Compared to White participants, eGFR-MDRD and eGFR-CKD-EPI equations in Black participants significantly overestimated GFR (bias 20.3 and 19.7 ml/min/1.73m2 respectively, p<0.001). Disregarding the ethnicity adjustment significantly improved GFR estimates for Black participants (bias 6.7 and 2.4ml/min/1.73m2 for eGFR-MDRD and eGFR-CKD-EPI respectively, p<0.001). The LM Revised equation had the smallest bias for both White and Black participants (5.8ml and -1.1ml/min/1.73m2 respectively). 30%-accuracy was superior for GFR≥60ml/min/1.73m2 compared to <60ml/min/1.73m2 using eGFR-CKD-EPI equation for both White and Black participants (p<0.001). Multivariate regression methodology with adjustment for age, sex and log(serum creatinine) in the cohort yielded an ethnicity coefficient of 1.018 (95% CI: 1.009-1.027). Overestimation of measured GFR with eGFR equations using ethnicity adjustment factors may lead to reduced CKD diagnosis and under-recognition of severity in people of Black ethnicity. Our findings suggest that ethnicity adjustment for GFR estimation in non-African Americans may not be appropriate for use in people of Black ethnicity in the UK.

Clinical, radiological, and laboratory predictors of a positive urine lipoarabinomannan test in sputum-scarce and sputum-negative patients with HIV-associated tuberculosis in two Johannesburg hospitals

Background

Tuberculosis (TB) is a major cause of mortality in persons living with HIV (PLWH). Sputum-based diagnosis of TB in patients with low CD4 counts is hampered by paucibacillary disease and consequent sputum scarcity or negative sputum results. Urine lipoarabinomannan (LAM) has shown promise in the point-of-care detection of TB in this patient subset but lacks sensitivity, and its exact role in a diagnostic algorithm for TB in South Africa remains to be clarified.

Objectives

The objective of this study was to better define the patient profile and the TB characteristics associated with a positive urine LAM (LAM+ve) test.

Method

This multicentre retrospective record review examined the clinical, radiological, and laboratory characteristics of hospitalised PLWH receiving urine LAM testing with sputum-scarce and/or negative sputum GeneXpert ^® (mycobacterium tuberculosis/resistance to rifampicin [MTB/RIF]) results.

Results

More than a third of patients, 121/342 (35%), were LAM+ve. The positive yield was greater in the sputum-scarce than the sputum-negative group, 66/156 (42%) versus 55/186 (30%), P = 0.0141, respectively. Patients who were LAM+ve were more likely to be confused (odds ratio [OR] = 2.2, 95% confidence interval [CI] = 1.2–3.7, P = 0.0045), have a higher median heart rate (P = 0.0135) and an elevated quick sepsis-related organ failure assessment score (≥ 2), OR = 3.5, 95% CI = 1.6–7.6, P = 0.0014. A LAM+ve test was significantly associated with disseminated TB (dTB), P < 0.0001, TB-related immune reconstitution inflammatory syndrome (IRIS), P = 0.0035, and abdominal TB, P < 0.0001. Laboratory predictors of a LAM+ve status included renal dysfunction, P = 0.044, severe anaemia, P = 0.0116, and an elevated C-reactive protein, P = 0.0131. Of the 12 PLWH with disseminated non-TB mycobacteria cultured from the blood and/or bone marrow, n = 9 (75%) had a LAM+ve result (OR = 5.8, 95% CI = 1.6–20.8, P = 0.0053).

Conclusion

Urine LAM testing of hospitalised PLWH with suspected active TB had significant diagnostic utility in those that were sputum-scarce or sputum-negative. A LAM+ve result was associated with dTB, clinical and laboratory markers of severe illness, and TB-IRIS. Disseminated non-tuberculous mycobacterial infection of hospitalised PLWH may also yield urine LAM+ve results, and mycobacterial cultures must be checked in those non-responsive to conventional TB treatment. Selective use of the LAM test in the critically ill is likely to maximise the diagnostic yield, improve the test’s predictive value, and reduce the time to TB diagnosis and initiation of treatment.

Hypertension in adolescents and young adults referred to a tertiary hypertension clinic in Cape Town, South Africa

To audit the young patients referred to the Hypertension Clinic at Groote Schuur Hospital that predominately serves the underprivileged communities of Cape Town.Folders of patients between the ages of 15 and 30 years over a 2 year period were reviewed. The data collected included demographic, clinical and laboratory data, investigations, causes of hypertension, and presence of hypertensive organ damage.Of the 110 patients reviewed, 61 (55.5%) were females, 22 (20%) Black African, and 88 (80%) of Mixed Ancestry. Eight (7.3%) were found to be normotensive, 16 (14.5%) had a secondary cause and 86 (78.2%) had essential hypertension. Thirty five (31.8%) were current or previous smokers, and 11 (10%) admitted to current or prior use of metamphetamines. A family history of hypertension in a first degree relative was present in 80 (72.7%) patients. Comorbidities present were diabetes in 7 (6.4%) patients, metabolic syndrome in 13 (11.8%), and obesity in 26 (23.6%), but 42.6% had a body mass index (BMI) <25 kg/m. Chronic kidney disease (CKD) was present in 29 (26.4%) patients and ECG left ventricular hypertrophy in 56 (50.9%). Overall organ damage was present in 72 (65.5%) patients.In this cohort of young hypertensives most patients had essential hypertension with a strong family history. Significant organ damage was identified. High risk behavior, including smoking and illicit drug use, and obesity were identified as contributing factors. Secondary causes were identified in 14.2%. These results suggest a targeted approach to the investigation of young hypertensives for secondary causes, and significant opportunities for lifestyle intervention.

On the Basis of Race: The Utility of a Race Factor in Estimating Glomerular Filtration

BACKGROUND

Glomerular filtration rate (GFR) is a measure of the combined rate of filtration of all functional nephrons in the kidney. Measurement of GFR is used in the clinic to detect, stratify, and monitor progression of kidney dysfunction, and also serves as a prognostic tool for staging chronic kidney disease (CKD). The gold standard method for measuring GFR is by plasma or urine clearance of exogenous filtration markers, but this is not feasible in routine clinical practice. The most commonly used method to assess GFR is using equations for estimated GFR (eGFR).

CONTENT

Addition of a race factor to eGFR equations has been recommended to optimize performance for Black individuals. Here, we review the basis of the race-based equation and assess its utility and widespread applicability.

SUMMARY

Although evidence supporting the performance of a race factor exists in the unique populations in which these estimation equations were derived, more studies are needed to assess the need, or lack thereof, for race factors for all ethnicities. Furthermore, ethnicity is complex and likely cannot be qualified with a 2-level descriptor.

Validity of Urine NGALds Dipstick for Acute Kidney Injury in a Malawian Trauma Cohort

Introduction

Acute kidney injury (AKI) is a major cause of mortality worldwide, particularly in low-resource settings with limited diagnostic testing. Neutrophil gelatinase-associated lipocalin (NGAL) has shown promise in predicting AKI. Nested within a larger, prospective cohort study evaluating AKI incidence in admitted trauma patients, our objective was to evaluate a novel dipstick, NGALds, for the prediction of AKI in Malawi, Africa.

Methods

Participants were >6 months of age. Spearman rank correlation coefficients (R) assessed NGAL categories (negative [≤50 ng/ml], low risk [51−149 ng/ml], moderate risk [150−299 ng/ml], and high risk [≥300 ng/ml]) for the urine NGALds dipstick and laboratory-based NGAL Test.

Results

We enrolled 285 participants (one-third children). Thirteen percent developed AKI. The dipstick captured 45 of 52 participants (86.5%) with moderate- or high-risk NGAL values on laboratory-based testing (R = 0.74). The dipstick had sensitivity of 44.4%, specificity of 73.5%, positive predictive value of 19.5%, and negative predictive value of 90.2% for predicting AKI. Acute kidney injury was associated with an increased risk of mortality (relative risk [RR] = 3.9, 95% confidence interval [CI] = 1.9−8.2), but mortality risk greatly increased among children who first had a positive (≥150 ng/ml) NGALds result (RR = 12.0, 95% CI = 1.8−78.4).

Conclusions

The NGALds dipstick performed similarly to the NGAL Test in this low-resource setting and may be a useful tool to rule out AKI. It may be even more important in predicting high mortality risk among children.

Association of Genetic Polymorphisms of TGF-β1, HMOX1, and APOL1 With CKD in Nigerian Patients With and Without HIV

RATIONALE & OBJECTIVE

Recent studies in the human immunodeficiency virus (HIV)-infected population have suggested that there are genetic predispositions to the development of chronic kidney disease (CKD) in this context. We investigated the association of genetic polymorphisms of the genes encoding apolipoprotein L1 (APOL1), transforming growth factor β1 (TGF-β1; a profibrotic cytokine), and heme oxygenase 1 (HMOX1) with prevalent CKD among adults with and without HIV infection.

STUDY DESIGN

Case-control study.

SETTING & PARTICIPANTS

West African adults including 217 HIV-infected patients with CKD (HIV⁺/CKD⁺ group), 595 HIV-infected patients without CKD (HIV⁺/CKD^- group), 269 with CKD and no HIV infection (HIV^-/CKD⁺ group), and 114 with neither CKD nor HIV (HIV^-/CKD^- group).

EXPOSURE

The genetic polymorphisms with reference single-nucleotide polymorphism (rs) identification numbers rs1800469 (TGF-β1), rs1800470 (TGF-β1), rs121918282 (TGF-β1); rs60910145 (APOL1 G1 risk allele), rs73885319 (APOL1 G1 risk allele), rs71785313 (APOL1 G2 risk allele), and rs743811 (HMOX1); HIV.

OUTCOME

CKD.

ANALYTICAL APPROACH

Single-nucleotide polymorphism (SNP) genotyping of rs1800469 (TGF-β1), rs1800470 (TGF-β1), rs121918282 (TGF-β1); rs60910145 (APOL1), rs73885319 (APOL1), rs71785313 (APOL1), and rs743811 (HMOX1) was performed. Hardy-Weinberg equilibrium was evaluated for all SNPs, and minor allele frequencies were reported. A case-control analysis was performed, and multivariable logistic regression was used to control for potential confounders.

RESULTS

Minor allele frequencies for TGF-β1 (rs1800469, rs1800470, and rs1800471), APOL1 (rs60910145, rs73885319, and rs71785313), and HMOX1 (rs743811) were 0.25, 0.46, 0.46, 0.44, 0.45, 0.17, and 0.14, respectively. Among HIV-positive individuals, only TGF-β1 rs1800470 (GG vs AA), APOL1 (in the recessive model), and hypertension were associated with prevalent CKD (adjusted ORs of 0.44 [95% CI, 0.20-0.97], 2.54 [95% CI, 1.44-4.51], and 2.17 [95% CI, 1.35-3.48], respectively). No SNP polymorphisms were associated with prevalent CKD among HIV-negative individuals.

LIMITATIONS

The lack of histopathology data for proper categorization of the type of HIV-related nephropathy.

CONCLUSIONS

APOL1 polymorphisms were highly prevalent in this population and among adult patients infected with HIV and were associated with increased CKD risk. The TGF-β1 (rs1800470) polymorphism was associated with reduced risk, and HMOX1 polymorphisms were unassociated with CKD.

How to estimate glomerular filtration rate in sub-Saharan Africa: design and methods of the African Research into Kidney Diseases (ARK) study

BACKGROUND

Chronic kidney disease (CKD) is a substantial cause of morbidity and mortality worldwide with disproportionate effects in sub-Saharan Africa (SSA). The optimal methods to estimate glomerular filtration rate (GFR) and therefore to determine the presence of CKD in SSA are uncertain. We plan to measure iohexol excretion to accurately determine GFR in Malawi, South Africa and Uganda. We will then assess the performance of existing equations to estimate GFR and determine whether a modified equation can better improve estimation of GFR in sub-Saharan Africa.

METHODS

The African Research on Kidney Disease (ARK) study is a three-country study embedded within existing cohorts. We seek to enrol 3000 adults > 18 years based on baseline serum creatinine. Study procedures include questionnaires on socio-demographics and established risk factors for kidney disease along with anthropometry, body composition, blood pressure, blood chemistry and urine microscopy and albuminuria. We will measure GFR (mGFR) by plasma clearance of iohexol at 120, 180 and 240 min. We will compare eGFR determined by established equations with mGFR using Bland-Altman plots. We will use regression methods to estimate GFR and compare the newly derived model with existing equations.

DISCUSSION

Through the ARK study, we aim to establish the optimal approach to estimate GFR in SSA. The study has the advantage of drawing participants from three countries, which will increase the applicability of the findings across the region. It is also embedded within established cohorts that have longitudinal information and serial measures that can be used to characterize kidney disease over a period of time. This will help to overcome the limitations of previous research, including small numbers, selected population sub-groups, and lack of data on proteinuria. The ARK collaboration provides an opportunity for close working partnerships across different centres, using standardized protocols and measurements, and shared bio-repositories. We plan to build on the collaboration for this study for future work on kidney disease in sub-Saharan Africa, and welcome additional partners from across the continent.

Methods and reporting of kidney function: a systematic review of studies from sub-Saharan Africa

Globally, chronic kidney disease (CKD) is an emerging public health challenge but accurate data on its true prevalence are scarce, particularly in poorly resourced regions such as sub-Saharan Africa (SSA). Limited funding for population-based studies, poor laboratory infrastructure and the absence of a validated estimating equation for kidney function in Africans are contributing factors. Consequently, most available studies used to estimate population prevalence are hospital-based, with small samples of participants who are at high risk for kidney disease. While serum creatinine is most commonly used to estimate glomerular filtration, there is considerable potential bias in the measurement of creatinine that might lead to inaccurate estimates of kidney disease at individual and population level. To address this, the Laboratory Working Group of the National Kidney Disease Education Program published recommendations in 2006 to standardize the laboratory measurement of creatinine. The primary objective of this review was to appraise implementation of these recommendations in studies conducted in SSA after 2006. Secondary objectives were to assess bias relating to choice of estimating equations for assessing glomerular function in Africans and to evaluate use of recommended diagnostic criteria for CKD. This study was registered with Prospero (CRD42017068151), and using PubMed, African Journals Online and Web of Science, 5845 abstracts were reviewed and 252 full-text articles included for narrative analysis. Overall, two-thirds of studies did not report laboratory methods for creatinine measurement and just over 80% did not report whether their creatinine measurement was isotope dilution mass spectroscopy (IDMS) traceable. For those reporting a method, Jaffe was the most common (93%). The four-variable Modification of Diet in Renal Disease (4-v MDRD) equation was most frequently used (42%), followed by the CKD Epidemiology Collaboration (CKD-EPI) equation for creatinine (26%). For the 4-v MDRD equation and CKD-EPI equations, respectively, one-third to one half of studies clarified use of the coefficient for African-American (AA) ethnicity. When reporting CKD prevalence, <15% of studies fulfilled Kidney Disease: Improving Global Outcomes criteria and even fewer used a population-based sample. Six studies compared performance of estimating equations to measured glomerular filtration rate (GFR) demonstrating that coefficients for AA ethnicity used in the 4-v MDRD and the CKD-EPI equations overestimated GFR in Africans. To improve on reporting in future studies, we propose an 'easy to use' checklist that will standardize reporting of kidney function and improve the quality of studies in the region. This research contributes some understanding of the factors requiring attention to ensure accurate assessment of the burden of kidney disease in SSA. Many of these factors are difficult to address and extend beyond individual researchers to health systems and governmental policy, but understanding the burden of kidney disease is a critical first step to informing an integrated public health response that would provide appropriate screening, prevention and management of kidney disease in countries from SSA. This is particularly relevant as CKD is a common pathway in both infectious and non-communicable diseases, and multimorbidity is now commonplace, and even more so when those living with severe kidney disease have limited or no access to renal replacement therapy.

Evaluation of the CKD-EPI creatinine based glomerular filtration rate estimating equation in Black African and Indian adults in KwaZulu-Natal, South Africa

BACKGROUND

The estimation of glomerular filtration rate (GFR) plays a vital role in assessment of the renal function. This study evaluated the performance of the CKD-EPIcreat and MDRD equations in the South African Kwa-Zulu Natal population.

OBJECTIVES

The objectives if the study were to compare the of CKD-EPIcreat and MDRD equations in the selected population to the measured GFR using Sodium Technetium-99 m-diethylene-triamine-pentaacetate clearance derived GFR.

METHOD

Records of adult patients with measured GFR performed at the Nuclear Medicine Department at Inkosi Albert Luthuli Central Hospital, Durban, South Africa from 1 April 2014 to 31 March 2016 were reviewed. eGFR for all included patients was calculated using the MDRD equation without African American correction factor and the CKD-EPIcreat equation with and without the African American correction factor for the Black African patients. Statistical comparison of the eGFR with measured GFR was performed with Bland Altman bias plots, Wilcoxon match pairs signed ranks test and accuracy within 10% and 30%.ROC curve analysis assessed the sensitivity and specificity at eGFR <90 and < 60 ml/min/1.73m2.

RESULTS

After exclusion, 287 patients were included for analysis with sufficient numbers for only the Black African and Indian patients. None of the equations showed accuracy of eGFR within 30% of measured GFR for 90% of patients. In the Black African population, the CKD-EPIcreat equation without the correction factor performed best. 17% and 14.4% of the Black African participants would be reclassified with the CKD-EPIcreat equation without and with the African American correction factor respectively compared to mGFR at a cut-off of 60 mls/min/1.73m2.

CONCLUSION

None of the evaluated equations attained the 2002 KDOQI benchmark of P30 >90%. 11.1-17% of individuals would have been incorrectly classified using the CKD-EPIcreat equation.

Chronic kidney disease in the global adult HIV-infected population: A systematic review and meta-analysis

INTRODUCTION

The widespread use of antiretroviral therapies (ART) has increased life expectancy in HIV patients, predisposing them to chronic non-communicable diseases including Chronic Kidney Disease (CKD). We performed a systematic review and meta-analysis (PROSPERO registration number CRD42016036246) to determine the global and regional prevalence of CKD in HIV patients.

METHODS

We searched PubMed, Web of Science, EBSCO and AJOL for articles published between January 1982 and May 2016. CKD was defined as estimated glomerular filtration rate (eGFR) <60ml/min using the MDRD, Cockcroft-Gault or CKD-EPI equations. Random effects model was used to combine prevalence estimates from across studies after variance stabilization via Freeman-Tukey transformation.

RESULT

Sixty-one eligible articles (n = 209,078 HIV patients) in 60 countries were selected. The overall CKD prevalence was 6.4% (95%CI 5.2-7.7%) with MDRD, 4.8% (95%CI 2.9-7.1%) with CKD-EPI and 12.3% (95%CI 8.4-16.7%) with Cockcroft-Gault; p = 0.003 for difference across estimators. Sub-group analysis identified differences in prevalence by WHO region with Africa having the highest MDRD-based prevalence at 7.9% (95%CI 5.2-11.1%). Within Africa, the pooled MDRD-based prevalence was highest in West Africa [14.6% (95%CI 9.9-20.0%)] and lowest in Southern Africa (3.2%, 95%CI 3.0-3.4%). The heterogeneity observed could be explained by WHO region, comorbid hypertension and diabetes mellitus, but not by gender, hepatitis B or C coinfection, CD4 count or antiretroviral status.

CONCLUSION

CKD is common in HIV-infected people, particularly in Africa. HIV treatment programs need to intensify screening for CKD with added need to introduce global guidelines for CKD identification and treatment in HIV positive patients.

Prevalence and burden of chronic kidney disease among the general population and high-risk groups in Africa: a systematic review

OBJECTIVES

While increasing attention is paid to the rising prevalence of chronic diseases in Africa, there is little focus on chronic kidney disease (CKD). This systematic review assesses CKD burden among the general population and high-risk groups on the entire African continent.

DESIGN, SETTING AND PARTICIPANTS

We searched Medline and PubMed databases for articles published between 1 January 1995 and 7 April 2017 by sensitive search strategies focusing on CKD surveys at the community level and high-risk groups. In total, 7918 references were evaluated, of which 7766 articles were excluded because they did not meet the inclusion criteria. Thus, 152 studies were included in the final analysis.

OUTCOME MEASUREMENT

The prevalence of CKD in each study group was expressed as a range and pooled prevalence rate of CKD was calculated as a point estimate and 95% CI. No meta-analysis was done. Data were presented for different populations.

RESULTS

In the community-level studies, based on available medium-quality and high-quality studies, the prevalence of CKD ranged from 2% to 41% (pooled prevalence: 10.1%; 95% CI 9.8% to 10.5%). The prevalence of CKD in the high-risk groups ranged from 1% to 46% (pooled prevalence: 5.6%; 95% CI 5.4% to 5.8%) in patients with HIV (based on available medium-quality and high-quality studies), 11%-90% (pooled prevalence: 24.7%; 95% CI 23.6% to 25.7%) in patients with diabetes (based on all available studies which are of low quality except four of medium quality) and 13%-51% (pooled prevalence: 34.5%; 95 % CI 34.04% to 36%) in patients with hypertension (based on all available studies which are of low quality except two of medium quality).

CONCLUSION

In Africa, CKD is a public health problem, mainly attributed to high-risk conditions as hypertension and diabetes. The poor data quality restricts the validity of the findings and draws the attention to the importance of designing future robust studies.

Concordance between modification of diet in renal disease, chronic kidney disease epidemiology collaboration and Cockcroft-Gault equations in patients with chronic kidney disease at St. Paul's hospital millennium medical college, Addis Ababa, Ethiopia

Background

The most commonly used glomerular filtration rate estimating equations for drug dosing are Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. However there is still a concern about whether to use MDRD and CKD-EPI interchangeably with CG for drug dosage adjustment.

Methods

The study was initiated to determine the concordance between MDRD, CKD-EPI and CG equations and associated factors in patients with chronic kidney disease at Saint Paul’s Hospital Millennium Medical College (SPHMMC). This was a cross sectional study which involved patient chart review and physicians self-administered questionnaire. Serum creatinine level ≥ 1.2 mg/dL was used as a cutoff point in pre-selection of patients. The correctness of the drug dose prescribed for the level of renal function were compared to the drug database (Lexi-Comp) available through Up-to-date version 21.2.

Results

Among the total of 422 patients, 249 (59%) were males. Mean age of patients was 46.09 years. The use of MDRD equation for drug dose adjustment by physicians working in the renal clinic of SPHMMC was six out of nine physicians. The Pearson correlation coefficient between the CG with MDRD and CKD-EPI equations was r = 0.94, P < 0.001 and r = 0.95, P < 0.001, respectively. The concordance between the CG with MDRD and CKD-EPI equations for FDA assigned kidney function categories was 73.7%, Kappa = 0.644 and 74.9%, Kappa = 0.659, respectively. Concordance between the CG with MDRD and CKD-EPI equations for the drug dosing recommendation was 89.6%, kappa = 0.782 and 92%, kappa = 0.834, respectively. Age > 70 years was associated with discordance between CG and MDRD equations for drug dosing recommendation whereas serum creatinine 1.2–3.5 mg/dL, weight < 61 Kg and age > 70 years were associated with discordance between the CG with MDRD and CKD-EPI equations for FDA assigned kidney function categories. However, none of the factors associated with discordance between CG and CKD-EPI for drug dosing.

Conclusion

MDRD equation can be used interchangeably with CG equation for drug dosing recommended in all adult patients between the age of 18 and 70 years. CKD-EPI can be used interchangeably with CG in all adult Ethiopian patients with CKD.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0783-3) contains supplementary material, which is available to authorized users.

Association of Kidney Function and Waist Circumference with Uric Acid Levels in South Africans

BACKGROUND

Recent evidence that hyperuricemia is associated with incident chronic kidney disease (CKD) provides a potential therapeutic target for CKD that has not been explored in Africans. With hyperuricemia and gout increasing globally, we sought to determine their prevalence in South Africans with varying kidney function levels.

METHODS

This was a cross-sectional study of ambulatory adult patients presenting at a General Internal Medicine Outpatients Clinic between September 2012 and March 2014. Demographic, clinical, and laboratory data collected were analyzed using STATA11. Odds ratios (ORs) and 95% confidence intervals were determined using multivariable logistic regression with bootstrapping.

RESULTS

There were 225/261 (86.2%) black/Africans, 31/261 (11.9%) Indian South Africans, 3/261 (1.1%) Caucasians, and 2/261 (<1%) mixed ancestry South Africans. Mean age was 51.3 ± 14.5 years. Median (interquartile range) estimated glomerular filtration rate (eGFR) was 71 (38) mL/min/1.73 m² and 39.8% (104/261) of patients had CKD. Hyperuricemia prevalence was 43.7% (114/261) and increased from 16.7% in patients with eGFR ≥90 mL/min/1.73 m² to 74.2% with eGFR <30 mL/min/1.73 m² (P < 0.001). Gout prevalence was 5.4% (14/261), with equal distribution across eGFR categories (0.814). Factors independently associated with hyperuricemia were eGFR <90 [ORs 3.24 (1.15-9.14), 7.28 (2.26-23.49), and 7.88 (1.95-31.82) for eGFR 60-89.9, 30-60, and <30, respectively], albuminuria [2.32 (1.11-4.85)], and waist circumference [1.04 (1.01-1.06) per 1 cm increase]. In univariate and multivariable analysis, gout was positively associated with male gender and cardiovascular disease, while it was negatively associated with African ancestry, but none of these factors remained significant after bootstrapping; ORs 6.65 (0.64-69.24), 4.14 (0.61-28.07), and 0.18 (0.01-2.21), respectively.

CONCLUSION

Hyperuricemia prevalence was high, with CKD and waist circumference being the strongest predictors. Gout was uncommon in black Africans. With population data lacking, screening high-risk individuals may provide insight into the burden of hyperuricemia and gout in South Africa.

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.

Prevalence of chronic kidney disease and association with cardiovascular risk factors among teachers in Cape Town, South Africa

Background: There is a need to determine the feasibility of conducting studies of chronic diseases among large cohorts of African patients. One aim of the South African feasibility study was to determine the prevalence of chronic kidney disease (CKD) and its association with cardiovascular disease (CVD) risk factors among school teachers. Methods: In a cross-sectional survey of 489 teachers we captured data on demographics, CVD risk factors, anthropometry and blood pressure. Serum glucose, creatinine, cholesterol and urine protein/creatinine ratio was measured. Glomerular filtration rate was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease study equations. Results: The mean (± standard deviation) age of the participants was 46.3 ± 8.5 years, with 70.3% being female and 74.6% of mixed ethnicity. The crude prevalence of CKD using the CKD-EPI equation was 6.1% while the age-adjusted prevalence was 6.4% (95% confidence interval 3.2-9.7%). CKD was associated with the presence of diabetes and higher diastolic blood pressures. Conclusions: In our study population of relatively young, working individuals CKD was common, clinically silent and associated with cardiovascular risk factors. The long-term complications of CKD are serious and expensive to manage and this, therefore, constitutes an important public health problem for South Africa.

Chronic kidney disease in low-income to middle-income countries: the case for increased screening

Chronic kidney disease (CKD) is fast becoming a major public health issue, disproportionately burdening low-income to middle-income countries, where detection rates remain low. We critically assessed the extant literature on CKD screening in low-income to middle-income countries. We performed a PubMed search, up to September 2016, for studies on CKD screening in low-income to middle-income countries. Relevant studies were summarised through key questions derived from the Wilson and Jungner criteria. We found that low-income to middle-income countries are ill-equipped to deal with the devastating consequences of CKD, particularly the late stages of the disease. There are acceptable and relatively simple tools that can aid CKD screening in these countries. Screening should primarily include high-risk individuals (those with hypertension, type 2 diabetes, HIV infection or aged >60 years), but also extend to those with suboptimal levels of risk (eg, prediabetes and prehypertension). Since screening for hypertension, type 2 diabetes and HIV infection is already included in clinical practice guidelines in resource-poor settings, it is conceivable to couple this with simple CKD screening tests. Effective implementation of CKD screening remains a challenge, and the cost-effectiveness of such an undertaking largely remains to be explored. In conclusion, for many compelling reasons, screening for CKD should be a policy priority in low-income to middle-income countries, as early intervention is likely to be effective in reducing the high burden of morbidity and mortality from CKD. This will help health systems to achieve cost-effective prevention.

Changes in estimated glomerular filtration rate over time in South African HIV-1-infected patients receiving tenofovir: a retrospective cohort study

Introduction: Tenofovir has been associated with decline in kidney function, but in patients with low baseline kidney function, improvements over time have been reported. Additionally, the magnitude and trajectory of estimated glomerular filtration rate (eGFR) changes may differ according to how eGFR is calculated. We described changes in eGFR over time, and the incidence of, and risk factors for, kidney toxicity, in a South African cohort.

Methods: We included antiretroviral-naïve patients ≥16 years old who started tenofovir-containing antiretroviral therapy (ART) between 2002 and 2013. We calculated eGFR using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Cockcroft-Gault equations. We described changes in eGFR from ART initiation using linear mixed effects regression. We described the incidence of eGFR <30 mL/min on treatment, and identified associations with low eGFR using Cox regression.

Results: We included 15156 patients with median age of 35.4 years (IQR 29.9–42.0), median CD4 cell count of 168 cells/µL (IQR 83–243), and median eGFR (MDRD) of 98.6 mL/min (IQR 84.4–115.6). Median duration of follow up on tenofovir was 12.9 months (IQR 5.1–23.3).

Amongst those with a baseline and subsequent eGFR  available, mean eGFR change from baseline at 12 months was −4.4 mL/min (95% CI −4.9 to −4.0), −2.3 (−2.5 to −2.1), and 0.6 (0.04 to 1.2) in those with baseline eGFR ≥90 mL/min; and 11.9 mL/min (11.0 to 12.7), 14.6 (13.5 to 15.7), and 11.0 (10.3 to 11.7) in those with baseline eGFR <90 mL/min, according to the MDRD, CKD-EPI (n = 11 112), and Cockcroft-Gault (n = 9 283) equations, respectively.

Overall, 292 (1.9%) patients developed eGFR <30 mL/min. Significant associations with low eGFR included older age, baseline eGFR <60 mL/min, CD4 count <200 cells/µL, body weight <60 kg, and concomitant protease inhibitor use.

Conclusions: Patients on tenofovir with baseline eGFR ≥90 mL/min experienced small but significant declines in eGFR over time when eGFR was estimated using the MDRD or CKD-EPI equations. However, eGFR increased in patients with eGFR <90 mL/min, regardless of which estimating equation was used. Decreases to below 30 mL/min were uncommon. In settings with limited access to laboratory testing, monitoring guidelines should consider focusing on higher risk patients.

Cystatin C- and creatinine-based equations in the assessment of renal function in HIV-positive patients prior to commencing Highly Active Antiretroviral Therapy

BACKGROUND

We evaluated the accuracy and precision of creatinine- and cystatin C-based prediction equations for estimating glomerular filtration rate compared to measured glomerular filtration rate in an antiretroviral-naive human immunodeficiency virus population.

METHODS

The study population consisted of 100 treatment-naive HIV patients. Glomerular filtration rate was estimated using the Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, as well as cystatin C-based equations (CKD-EPIcystatin C, cystatin Cvan Deventer and CKD-EPIcombined)) compared to (51)Cr-EDTA plasma clearance-measured glomerular filtration rate. We calculated percentage bias, standard deviation of the differences, accuracy within 15 and 30% of measured glomerular filtration rate and sensitivity and specificity for predicting measured glomerular filtration rate <60 mL/min/1.73 m(2).

RESULTS

Bias for all estimating glomerular filtration rate equations ranged from -9.4% to 38.4%. The CKD-EPIcombined without ethnicity correction factor equation had the least bias, 2.9% (-2.9 to 8.8). Bias was higher for the Modification of Diet in Renal Disease and CKD-EPI equation with the African-American ethnicity factor (38.4 and 33.7%) than without (14.2 and 15.3%). Standard deviation of the differences ranged from 29.2% (CKD-EPIcombined without ethnicity factor) to 54.0% (Modification of Diet in Renal Disease with ethnicity factor). Accuracy within 30% of measured glomerular filtration rate ranged from 78% for CKD-EPIcombined without ethnicity factor to 56.7% for the Cockcroft-Gault equation. Sensitivity for creatinine-based equations was less than 50% and for the CKD-EPIcystatin C equation was 75%.

CONCLUSION

Sensitivity of creatinine-based equations for predicting glomerular filtration rate was poor in this group of patients. The CKD-EPIcombined equation performed better than creatinine-based equations.

Characteristics of South African patients presenting with kidney disease in rural KwaZulu-Natal: a cross sectional study

Background

Diabetes mellitus is the leading cause of end-stage renal disease (ESRD) globally. Diabetes and human immunodeficiency virus (HIV), both prevalent in South Africa, have not been reported as significant causes of ESRD.

Methods

We evaluated chronic kidney disease (CKD) and cardiovascular disease risk factors in a cross-sectional study of 302 patients (165 females/ 137 males) at a CKD clinic in rural northern KwaZulu-Natal. We included all CKD outpatient clinic attendees and excluded acute renal failure patients. Demographic, clinical and laboratory data collected were analyzed with Stata11 software. Logistic regression analysis was used to determine factors associated with advanced CKD and results expressed as the odds ratio with the 95% confidence interval [OR (95% CI)].

Results

Of 302 patients analyzed, 290 (96%) were black African. Mean age ± SD was 47.1 ± 17.0 years. Approximately 86.4% of females and 54.5% of males were overweight/ obese. Dyslipidaemia was observed in 47.9% females and 29.2% males (P < 0.001). Estimated glomerular filtration rate (eGFR) was <30 ml/min/1.73 m² in 50.6% patients. CKD risk factors observed were: hypertension (77.8%), diabetes (29.8%), HIV (28.5%), glomerulonephritis (7.0%) and tubulointerstitial diseases (5.6%). Independent factors associated with eGFR <30 ml/min/1.73 m² at presentation were: HIV [OR = 2.4 (1.3-4.2), P = 0.004] and hypertension [OR = 2.3 (1.3-4.2), P = 0.007].

Conclusion

Diabetes and HIV are prevalent in CKD patients at primary/regional level healthcare in South Africa. With registry data lacking, dedicated CKD clinics at lower healthcare levels may provide valuable data on CKD epidemiology including changes in aetiology. Primary healthcare practitioners are faced with advanced CKD patients in resource-poor settings, with limited opportunity for upward referral hence the need for nephrology outreach programs.

The eGFR-C study: accuracy of glomerular filtration rate (GFR) estimation using creatinine and cystatin C and albuminuria for monitoring disease progression in patients with stage 3 chronic kidney disease--prospective longitudinal study in a multiethnic population

BACKGROUND

Uncertainty exists regarding the optimal method to estimate glomerular filtration rate (GFR) for disease detection and monitoring. Widely used GFR estimates have not been validated in British ethnic minority populations.

METHODS/DESIGN

Iohexol measured GFR will be the reference against which each estimating equation will be compared. The estimating equations will be based upon serum creatinine and/or cystatin C. The eGFR-C study has 5 components: 1) A prospective longitudinal cohort study of 1300 adults with stage 3 chronic kidney disease followed for 3 years with reference (measured) GFR and test (estimated GFR [eGFR] and urinary albumin-to-creatinine ratio) measurements at baseline and 3 years. Test measurements will also be undertaken every 6 months. The study population will include a representative sample of South-Asians and African-Caribbeans. People with diabetes and proteinuria (ACR ≥30 mg/mmol) will comprise 20-30% of the study cohort.2) A sub-study of patterns of disease progression of 375 people (125 each of Caucasian, Asian and African-Caribbean origin; in each case containing subjects at high and low risk of renal progression). Additional reference GFR measurements will be undertaken after 1 and 2 years to enable a model of disease progression and error to be built.3) A biological variability study to establish reference change values for reference and test measures.4) A modelling study of the performance of monitoring strategies on detecting progression, utilising estimates of accuracy, patterns of disease progression and estimates of measurement error from studies 1), 2) and 3).5) A comprehensive cost database for each diagnostic approach will be developed to enable cost-effectiveness modelling of the optimal strategy.The performance of the estimating equations will be evaluated by assessing bias, precision and accuracy. Data will be modelled as a linear function of time utilising all available (maximum 7) time points compared with the difference between baseline and final reference values. The percentage of participants demonstrating large error with the respective estimating equations will be compared. Predictive value of GFR estimates and albumin-to-creatinine ratio will be compared amongst subjects that do or do not show progressive kidney function decline.

DISCUSSION

The eGFR-C study will provide evidence to inform the optimal GFR estimate to be used in clinical practice.

TRIAL REGISTRATION

ISRCTN42955626.

Chronic kidney diseases in mixed ancestry south African populations: prevalence, determinants and concordance between kidney function estimators

BACKGROUND

Population-based data on the burden of chronic kidney disease (CKD) in sub-Saharan Africa is still very limited. We assessed the prevalence and determinants of CKD, and evaluated the concordance of commonly advocated estimators of glomerular filtration rate (eGFR) in a mixed ancestry population from South Africa.

METHODS

Participants were a population-based sample of adults selected from the Bellville-South community in the metropolitan city of Cape Town. eGFR was based on the Cockroft-Gault (CG), Modification of Diet in Kidney Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) equations (with and without adjustment for ethnicity). Kidney function staging used the Kidney Disease Outcome Quality Initiative (KDOQI) classification. Logistic regressions and kappa statistic were used to investigate determinants of CKD and assess the agreement between different estimators.

RESULTS

The crude prevalence of CKD stage 3-5 was 14.8% for Cockcroft-Gault, 7.6% and 23.9% respectively for the MDRD with and without ethnicity correction, and 7.4% and 17.3% for the CKD-EPI equations with and without ethnicity correction. The highest agreement between GFR estimators was between MDRD and CKD-EPI equations, both with ethnicity correction, Kappa 0.91 (95% CI: 0.86-0.95), correlation coefficient 0.95 (95% CI: 0.94-0.96). In multivariable logistic regression models, sex, age and known hypertension were consistently associated with CKD stage 3-5 across the 5 estimators.

CONCLUSIONS

The prevalence of CKD stages greater than 3 is the highest reported in Africa. This study provides evidence for support of the CKD-EPI equation for eGFR reporting and CKD classification.

Slow early graft function: a neglected entity after renal transplantation

BACKGROUND

After renal transplantation, early graft function (EGF) can be divided into delayed graft function (DGF), slow graft function (SGF) and immediate graft function (IGF). DGF is well documented. However, when evaluating the long-term significance of early function, the literature shows conflicting definitions and inconsistent results. In addition, SGF, a new entity separate to DGF and IGF, is a recent and poorly understood development.

AIM

To investigate the risk factors for and the impact of poor EGF (PEGF) on long-term outcome.

METHODS

This retrospective study reviewed the records of local adult patients who underwent renal transplantation at the Groote Schuur Hospital (Cape Town, South Africa) between 2004 and 2008. EGF was divided according to day 5 serum creatinine into IGF (serum creatinine <150 µmol/l), SGF (serum creatinine >150 but <450 µmol/l) and DGF (serum creatinine >450 µmol/l or dialysis in the first week). DGF and SGF together comprised PEGF, with IGF alone representing good EGF (GEGF).

RESULTS

A total of 121 patients (77 men, 44 women; mean age 39 years, range 14-67) were included in the study. Eighteen were excluded due to nephrectomy (n = 8), death (n = 6) or loss to follow-up (n = 4) within the first year. Analysis of cadaveric donors showed no significant risk factors for PEGF with the exception of cold ischaemic time, which differed significantly between the GEGF and PEGF groups, with means of 12 and 16 h, respectively (p = 0.013). Considering both living and cadaveric grafts, the 1-year estimated glomerular filtration rate (eGFR) was significantly different between IGF and DGF (p = 0.038) as well as between IGF and SGF (p = 0.028), with no significant difference between SGF and DGF (p > 0.05). A comparison of the PEGF and GEGF groups yielded significantly different 1-year eGFR values (60 and 50 ml/min, respectively; p = 0.07), with PEGF also associated with a longer hospital stay (20 vs. 14 days; p = 0.00005). Acute rejection was independently associated with a lower 1-year eGFR (p = 0.028), but in the absence of rejection, GEGF and PEGF remained significantly different with regards to 1-year eGFR (p = 0.024).

CONCLUSIONS

SGF is not related to IGF but rather to DGF and should thus be regarded as a form of PEGF as opposed to GEGF. PEGF has a worse long-term outcome, and this indicates the need for increased efforts in its prevention and greater attention to its management.