Lupus activity and outcomes in lupus patients undergoing maintenance dialysis.

OBJECTIVES: Lupus activity has long been considered to decline after initiation of maintenance dialysis (MD). This assumption is based on limited historical data. We aimed to describe the natural history of lupus in patients undergoing MD. METHODS: We assembled a national retrospective cohort of lupus patients who started dialysis between 2008 and 2011, included in the REIN registry with a 5-year follow-up. We analysed healthcare consumption from the National Health Data System. We evaluated the proportion of patients 'off-treatment' (i.e. receiving 0-5 mg/d of corticosteroids, without any immunosuppressive therapy) after the start of MD. We describe the cumulative incidences of non-severe and severe lupus flares, cardiovascular events, severe infections, kidney transplantation and survival. RESULTS: We included 137 patients (121 females and 16 males), with a median age of 42 years. The proportion of patients 'off-treatment' at dialysis initiation was 67.7% (95% CI: 61.8, 73.8%), and increased to 76.0% (95% CI: 73.3, 78.8) at 1 year and 83.4% (95% CI: 81.0, 85.9%) at 3 years, with a lower proportion in younger patients. Lupus flares mainly occurred in the first year after MD initiation, and at 12 months 51.6% of patients had presented a non-severe lupus flare and 11.6% a severe lupus flare. In addition, 42.2% (95% CI: 32.9, 50.3%) and 23.7% (95% CI: 16.0, 30.7%) of patients at 12 months had been hospitalized for cardiovascular events or infections, respectively. CONCLUSION: The proportion of lupus patients off-treatment increases after MD initiation, but non-severe and severe lupus flares continue to occur, mainly during the first year. This calls for the continued follow-up of lupus patients by lupus specialists after dialysis initiation.

A call for promoting living kidney donation in France in 2023 / Pourquoi développer la greffe de rein à partir de donneurs vivants en France en 2023 ?

Kidney transplantation from living donors is particularly under-developed in France in comparison with the US and most European countries. Among others, the lack of a proactive and evidence-based communication from French health providers is a potential cause that has been overlooked thus far. With this as a backdrop, the SFNDT Commission of transplantation has elaborated a 10 points-call for promoting living kidney transplantation in France in 2023 with the aims at (1) providing the entire nephrology community with a scientific rationale and (2) strenghtening the conviction of health providers, patients, and their relatives regarding the relevance of this modality of kidney transplantation.

La transplantation rénale à partir de donneur vivant est une activité qui reste insuffisamment développée en France. Ceci est particulièrement vrai en comparaison à la majorité des pays nord-américains et européens. Les raisons en sont multiples et incluent un défaut de communication proactive et argumentée par les acteurs de soins. La communication, l'information et finalement la promotion de la greffe à partir de donneurs vivants sont l'affaire de l'ensemble de la communauté néphrologique et, au premier rang, des néphrologues non spécifiquement impliqués en transplantation. C'est dans cet esprit que la Commission Transplantation de la Société francophone de néphrologie, dialyse et transplantation (SFNDT) a travaillé à l'élaboration d'un plaidoyer en tentant de répondre, en dix points, à la question « Pourquoi faut-il développer la transplantation rénale à partir de donneurs vivants en France en 2023 ? ¼. L'objectif est double : (1) fournir les principales bases d'une information scientifiquement argumentée et (2) renforcer la conviction de l'ensemble des acteurs de soins et des patients du bien-fondé de cette modalité de greffe.

Performance of creatinine-based equations to estimate glomerular filtration rate in White and Black populations in Europe, Brazil and Africa.

BACKGROUND: A new Chronic Kidney Disease Epidemiology Collaboration equation without the race variable has been recently proposed (CKD-EPIAS). This equation has neither been validated outside USA nor compared with the new European Kidney Function Consortium (EKFC) and Lund-Malmö Revised (LMREV) equations, developed in European cohorts. METHODS: Standardized creatinine and measured glomerular filtration rate (GFR) from the European EKFC cohorts (n = 13 856 including 6031 individuals in the external validation cohort), from France (n = 4429, including 964 Black Europeans), from Brazil (n = 100) and from Africa (n = 508) were used to test the performances of the equations. A matched analysis between White Europeans and Black Africans or Black Europeans was performed. RESULTS: In White Europeans (n = 9496), both the EKFC and LMREV equations outperformed CKD-EPIAS (bias of -0.6 and -3.2, respectively versus 5.0 mL/min/1.73 m², and accuracy within 30% of 86.9 and 87.4, respectively, versus 80.9%). In Black Europeans and Black Africans, the best performance was observed with the EKFC equation using a specific Q-value (= concentration of serum creatinine in healthy males and females). These results were confirmed in matched analyses, which showed that serum creatinine concentrations were different in White Europeans, Black Europeans and Black Africans for the same measured GFR, age, sex and body mass index. Creatinine differences were more relevant in males. CONCLUSION: In a European and African cohort, the performances of CKD-EPIAS remain suboptimal. The EKFC equation, using usual or dedicated population-specific Q-values, presents the best performance in the whole age range in the European and African populations included in this study.

Allograft function and muscle mass evolution after kidney transplantation.

BACKGROUND: Advanced chronic kidney disease is associated with muscle wasting, but how glomerular filtration rate (GFR) recovery after kidney transplantation is associated with muscle mass is unknown. METHODS: We took advantage of the simultaneous measurement of GFR (using iohexol plasma clearance; ioGFR) and creatinine excretion rate (a surrogate marker of muscle mass; CER) performed 3 months after transplantation and at a later time point at our institution to investigate the interplay between allograft function, muscle mass, and outcome in kidney transplant recipients. RESULTS: Between June 2005 and October 2019, 1319 successive kidney transplant recipients (mean age 50.4 ± 14.6; 38.7% female) underwent GFR measurement at our institution 3 months after kidney transplantation. CER (CER3 ) and ioGFR (ioGFR3 ) were 7.7 ± 2.6 µmol/min and 53 ± 17.1 mL/min/1.73 m2 , respectively. Multivariable analysis identified female gender, older donor and recipient age, reduced body mass index, coronary disease, dialysis history, proteinuria, and reduced ioGFR3 as independent predictors of low CER3 (ioGFR3 : ß coefficient 0.19 [95% confidence interval 0.14 to 0.24]). A total of 1165 patients had a subsequent CER measurement after a median follow-up of 9.5 months. Of them, 373 (32%) experienced an increase in CER > 10%, while 222 (19%) showed a CER decrease of more than 10%. Multivariable analysis adjusted for CER3 and other confounders identified ioGFR3 as an independent predictor of CER at follow-up (ß coefficient 0.11 [95% confidence interval 0.07 to 0.16]). In multivariable Cox analysis, reduced CER at 3 months or at follow-up were consistently associated with mortality (hazard ratio [95% confidence interval] at 3 months: 0.82 [0.74 to 0.91]; at follow-up: 0.79 [0.69 to 0.99]) but not with graft loss. CONCLUSIONS: Glomerular filtration rate recovery is a determinant of muscle mass variation after kidney transplantation. Early interventions targeting muscle mass gain may be beneficial for kidney transplant recipients.

Kidney glomerular filtration rate plasticity after transplantation.

Since the first living donor kidney transplantation about six decades ago, significant progress has been made in terms of extending allograft survival. However, to date, only a small number of studies have compared the functional changes of the donated kidney to that of the remaining kidney. Although relatively small, the study by Gonzalez Rinne et al. demonstrated the adaptive capacity of the transplanted kidney in 30 donor-recipient pairs. The glomerular filtration rate (GFR) in both donors and recipients was obtained 12 months after transplantation and the authors identified three scenarios: (i) where donors had a higher GFR than recipients; (ii) where donors had a lower GFR than recipients; and (iii) where donors had a similar GFR to recipients. The mechanisms mediating GFR adaptability after kidney transplantation seem to be associated with body surface area (including sex differences in body surface area). Microstructural analysis of human and animal models of renal physiology provides some clues to the physiological adaptation of the transplanted organ. The nephron number from endowment and age-related loss and the adaptive ability for compensatory glomerular hyperfiltration likely play a major role.

FIBER-ML, an Open-Source Supervised Machine Learning Tool for Quantification of Fibrosis in Tissue Sections.

Pathologic fibrosis is a major hallmark of tissue insult in many chronic diseases. Although the amount of fibrosis is recognized as a direct indicator of the extent of disease, there is no consentaneous method for its quantification in tissue sections. This study tested FIBER-ML, a semi-automated, open-source freeware that uses a machine-learning approach to quantify fibrosis automatically after a short user-controlled learning phase. Fibrosis was quantified in sirius red-stained tissue sections from two fibrogenic animal models: acute stress-induced cardiomyopathy in rats (Takotsubo syndrome-like) and HIV-induced nephropathy in mice (chronic kidney disease). The quantitative results of FIBER-ML software version 1.0 were compared with those of ImageJ in Takotsubo syndrome, and with those of inForm in chronic kidney disease. Intra- and inter-operator and inter-software correlation and agreement were assessed. All correlations were excellent (>0.95) in both data sets. The values of discriminatory power between the pathologic and healthy groups were <10-3 for data on Takotsubo syndrome and <10-4 for data on chronic kidney disease. Intra-operator agreement, assessed by intra-class coefficient correlation, was good (>0.8), while inter-operator and inter-software agreement ranged from moderate to good (>0.7). FIBER-ML performed in a fast and user-friendly manner, with reproducible and consistent quantification of fibrosis in tissue sections. It offers an open-source alternative to currently used software, including quality control and file management.

Age-adapted percentiles of measured glomerular filtration in healthy individuals: extrapolation to living kidney donors over 65 years.

OBJECTIVES: Most data on glomerular filtration rate (GFR) originate from subjects <65 years old, complicating decision-making in elderly living kidney donors. In this retrospective multi-center study, we calculated percentiles of measured GFR (mGFR) in donors <65 years old and extrapolated these to donors ≥65 years old. METHODS: mGFR percentiles were calculated from a development cohort of French/Belgian living kidney donors <65 years (n=1,983), using quantiles modeled as cubic splines (two linear parts joining at 40 years). Percentiles were extrapolated and validated in an internal cohort of donors ≥65 years (n=147, France) and external cohort of donors and healthy subjects ≥65 years (n=329, Germany, Sweden, Norway, France, The Netherlands) by calculating percentages within the extrapolated 5th-95th percentile (P5-P95). RESULTS: Individuals in the development cohort had a higher mGFR (99.9 ± 16.4 vs. 86.4 ± 14 and 82.7 ± 15.5 mL/min/1.73 m2) compared to the individuals in the validation cohorts. In the internal validation cohort, none (0%) had mGFR below the extrapolated P5, 12 (8.2%) above P95 and 135 (91.8%) between P5-P95. In the external validation cohort, five subjects had mGFR below the extrapolated P5 (1.5%), 25 above P95 (7.6%) and 299 (90.9%) between P5-P95. CONCLUSIONS: We demonstrate that extrapolation of mGFR from younger donors is possible and might aid with decision-making in elderly donors.

Performance of creatinine-based equations to estimate glomerular filtration rate with a methodology adapted to the context of drug dosage adjustment.

AIM: The Cockcroft-Gault (CG) creatinine-based equation is still used to estimate glomerular filtration rate (eGFR) for drug dosage adjustment. Incorrect eGFR may lead to hazardous over- or underdosing. METHODS: In a cross-sectional analysis, CG was validated against measured GFR (mGFR) in 14 804 participants and compared with the Modification-of-Diet-in-Renal-Diseases (MDRD), Chronic-Kidney-Disease-Epidemiology (CKD-EPI), Lund-Malmö-Revised (LMR) and European-Kidney-Function-Consortium (EKFC) equations. Validation focused on bias, imprecision and accuracy (percentage of estimates within ±30% of mGFR, P30), overall and stratified for mGFR, age and body mass index at mGFR <60 mL/min, as well as classification in mGFR stages. RESULTS: The CG equation performed worse than the other equations, overall and in mGFR, age and BMI subgroups in terms of bias (systematic overestimation), imprecision and accuracy except for patients ≥65 years where bias and P30 were similar to MDRD and CKD-EPI, but worse than LMR and EKFC. In subjects with mGFR <60 mL/min and at BMI 18.5-25 kg/m2 , all equations performed similarly, and for BMI < 18.5 kg/m2 CG and LMR had the best results though all equations had poor P30-accuracy. At BMI ≥ 25 kg/m2 the bias of the CG increased with increasing BMI (+17.2 mL/min at BMI ≥ 40 kg/m2 ). The four more recent equations also classified mGFR stages better than CG. CONCLUSIONS: The CG equation showed poor ability to estimate GFR overall and in analyses stratified for mGFR, age and BMI. CG was inferior to correctly classify the patients in the mGFR staging compared to more recent creatinine-based equations.

[Assessment of renal function of living kidney donors]. / Évaluation de la fonction rénale des donneurs vivants de rein.

Assessment of renal function of living kidney donors. After donation, glomerular filtration rate (GFR) of the donor is on average 75% of its predonation value, by the mean of a compensatory response of the remaining kidney. The GFR thresholds used to define kidney disease in the general population do not apply to living donors. For donors, the risk of end-stage kidney disease (ESKD) is much lower than that of the general population but higher than that of a healthy non-donor population. Most cases of ESKD are due to diabetes and hypertension that occur more than 10 years after donation. Living kidney donors should be healthy at the time of donation and should benefit from an extended annual follow-up for kidney disease screening. The GFR must be measured by an exogenous tracer for all living kidney donors. The value of GFR must be interpreted according to the age of the candidate. The predicted risk of ESKD in the absence of kidney donation may be helpful to guide the decision.

Évaluation de la fonction rénale des donneurs vivants de rein. Dans les années qui suivent le don, l'hypertrophie compensatrice du rein restant du donneur permet d'obtenir un débit de filtration glomérulaire (DFG) en moyenne à 75 % de sa valeur préopératoire. Les seuils de DFG retenus pour définir la maladie rénale en population générale ne s'appliquent pas aux donneurs vivants. Le risque d'insuffisance rénale terminale des donneurs est très inférieur à celui de la population générale mais supérieur à celui d'une population de non-donneurs en bonne santé. La majorité des cas d'insuffisance rénale chronique terminale est due au diabète et à l'hypertension artérielle, qui surviennent plus de 10 ans après le don. Les donneurs vivants de rein doivent être en bonne santé au moment du don et bénéficier d'un suivi annuel prolongé pour le dépistage des maladies rénales. L'évaluation de la fonction rénale des donneurs repose sur la mesure du DFG par un traceur exogène, cette valeur doit être interprétée en fonction de l'âge de l'individu. Le calcul du risque d'insuffisance rénale chronique terminale en l'absence de don de rein peut être utile à la décision.

Assessment of kidney function: clinical indications for measured GFR.

In the vast majority of cases, glomerular filtration rate (GFR) is estimated using serum creatinine, which is highly influenced by age, sex, muscle mass, body composition, severe chronic illness and many other factors. This often leads to misclassification of patients or potentially puts patients at risk for inappropriate clinical decisions. Possible solutions are the use of cystatin C as an alternative endogenous marker or performing direct measurement of GFR using an exogenous marker such as iohexol. The purpose of this review is to highlight clinical scenarios and conditions such as extreme body composition, Black race, disagreement between creatinine- and cystatin C-based estimated GFR (eGFR), drug dosing, liver cirrhosis, advanced chronic kidney disease and the transition to kidney replacement therapy, non-kidney solid organ transplant recipients and living kidney donors where creatinine-based GFR estimation may be invalid. In contrast to the majority of literature on measured GFR (mGFR), this review does not include aspects of mGFR for research or public health settings but aims to reach practicing clinicians and raise their understanding of the substantial limitations of creatinine. While including cystatin C as a renal biomarker in GFR estimating equations has been shown to increase the accuracy of the GFR estimate, there are also limitations to eGFR based on cystatin C alone or the combination of creatinine and cystatin C in the clinical scenarios described above that can be overcome by measuring GFR with an exogenous marker. We acknowledge that mGFR is not readily available in many centres but hope that this review will highlight and promote the expansion of kidney function diagnostics using standardized mGFR procedures as an important milestone towards more accurate and personalized medicine.

Comparison of Plasma Clearance With Early-Compartment Correction Equations and Urinary Clearance in High GFR Ranges.

INTRODUCTION: Glomerular filtration rate (GFR) is measured from the late plasma disappearance curve of an exogenous tracer, after correction for the early decay-corresponding to the distribution of the tracer-using various equations. These equations display the highest discrepancies in the GFR range above 90 ml/min per 1.73 m2, and their respective performances against a reference, urinary GFR measurement are unclear. METHODS: In patients with mGFR >90 ml/min per 1.73 m2 from 6 different cohorts, we compared GFR obtained from the plasma clearance of iohexol or 51Cr-ethylenediamine tetraacetic acid (EDTA), after correction using Chantler (C), Bröchner-Mortensen (BM), Fleming (F), Jodal-Bröchner-Mortensen (JBM), and Ng (N) equations, with urinary clearance of the same tracers or inulin. RESULTS: In 438 participants (median age 41 [39-42] years, 43% women), the median urinary clearance was 100.8 (94.7-112.6) ml/min per 1.73 m2. Plasma clearances using the correction equations were 105.7 (96.8-119.2), 102.4 (95.2-112.9), 100.7 (93.6-111.1), 102.6 (95.2-113.4), and 106.0 (98.2-117.6) ml/min per 1.73 m2 for C, BM, F, JBM, and N, respectively. Concordance correlation coefficients between plasma and urinary clearances were poor for all equations. Compared with urinary clearances, BM, F, and JBM displayed the best accuracy within 10% (73%, 72%, and 71%, respectively, vs. 63% and 66% for C and N), whereas BM and JBM had the lowest median biases. Accuracy of all equations was especially low in the hyperfiltration range (urinary clearance >130 ml/min per 1.73 m2). CONCLUSION: The BM and JBM equations displayed the best overall performances to correct for the early disappearance curve. Results of these equations should be interpreted with caution, especially in the highest GFR range.

The spectrum of kidney function alterations in adolescents with a solitary functioning kidney.

BACKGROUND: A precise assessment of glomerular filtration rate is key to delineate the care of children with a solitary functioning kidney (SFK). Data regarding measured GFR (mGFR) in this population is restricted to a single study of 77 individuals, which suggested that a GFR estimation (eGFR) method based on creatinine and cystatin C (eGFR-CKiD2) performed better than Schwartz's equation (eGFR-Schwartz). METHODS: We measured GFR in 210 consecutive adolescents (7 to 22 years old) with an SFK referred to our institution between 2014 and 2019 and in 43 young candidates for kidney donation (18 to 25 years old). We compared the distribution of mGFR in both groups and determined the factors associated with reduced mGFR in adolescents with an SFK. We further compared different eGFR formulas with mGFR and assessed the association of mGFR and eGFRs with PTH and FGF23, two early indicators of GFR reduction. RESULTS: While adolescents with an SFK had a similar median mGFR to healthy controls (103 ± 24ml/min/1.73m2 vs. 107 ± 12 ml/min/1.73m2), the fraction of individuals with an mGFR below 90 ml/min/1.73m2 was higher in patients with SFK (23% vs. 5% in controls; P = 0.005). Multiple linear regression identified older age, ipsilateral abnormalities of the urinary tract, lack of compensatory hypertrophy, and treated hypertension as independent factors associated with reduced mGFR. A smaller bias using eGFR-Schwartz (95% confidence interval (95%CI): 3 to 7) was revealed when compared to other eGFR. Compared to eGFR-Schwartz, mGFR showed a stronger correlation with PTH (r = 0.04 vs. r = 0.1) and FGF23 (r = 0.03 vs. r = 0.05). CONCLUSION: SFK is not a benign condition, since 20% of the patients display altered kidney function. Our results raise caution regarding the use of the cystatin-based equation. mGFR shows a better ability than eGFR-Schwartz to differentiate patients showing early homeostatic adaptation to GFR reduction.

Living kidney donor evaluation for all candidates with normal estimated GFR for age.

Multiple days assessments are frequent for the evaluation of candidates to living kidney donation, combined with an early GFR estimation (eGFR). Living kidney donation is questionable when eGFR is <90 ml/min/1.73 m2 (KDIGO guidelines) or 80 ml/min/1.73 m2 (most US centres). However, age-related GFR decline results in a lower eGFR for older candidates. That may limit the number of older kidney donors. Yet, continuing the screening with a GFR measure increases the number of eligible donors. We hypothesized that in-depth screening should be proposed to all candidates with a normal eGFR for age. We compared the evolution of eGFR after donation between three groups of predonation eGFR: normal for age (Sage ) higher than 90 or 80 ml/min/1.73 m2 (S90 and S80, respectively); across three age groups (<45, 45-55, >55 years) in a population of 1825 French living kidney donors with a median follow-up of 5.9 years. In donors younger than 45, postdonation eGFR, absolute- and relative-eGFR variation were not different between the three groups. For older donors, postdonation eGFR was higher in S90 than in S80 or Sage but other comparators were identical. Postdonation eGFR slope was comparable between all groups. Our results are in favour of in-depth screening for all candidates to donation with a normal eGFR for age.

The spectrum of kidney biopsies in hospitalized patients with COVID-19, acute kidney injury, and/or proteinuria.

We report a multicentric retrospective case series of patients with COVID-19 who developed acute kidney injury and/or proteinuria and underwent a kidney biopsy in the Paris and its metropolitan area. Forty-seven patients (80.9% men) with COVID-19 who underwent a kidney biopsy between March 08 and May 19, 2020 were included. Median age was 63 years IQR [52-69]. Comorbidities included hypertension (66.0%), diabetes mellitus (27.7%), obesity (27.7%), history of chronic kidney (25.5%), cardiac (38.6%) and respiratory (27.3%) diseases. Initial symptoms were fever (85.1%), cough (63.8%), shortness of breath (55.3%), and diarrhea (23.4%). Almost all patients developed acute kidney injury (97.9%) and 63.8% required renal replacement therapy. Kidney biopsy showed two main histopathological patterns, including acute tubular injury in 20 (42.6%) patients, and glomerular injury consisting of collapsing glomerulopathy and focal segmental glomerulosclerosis in 17 (36.2%) patients. Two (4.3%) patients had acute vascular nephropathy, while eight (17%) had alternative diagnosis most likely unrelated to COVID-19. Acute tubular injury occurred almost invariably in the setting of severe forms of COVID-19, whereas patients with glomerular injury had various profiles of COVID-19 severity and collapsing glomerulopathy was only observed in patients harboring a combination of APOL1 risk variants. At last follow-up, 16 of the 30 patients who initially required dialysis were still on dialysis, and 9 died. The present study describes the spectrum of kidney lesions in patients with COVID-19. While acute tubular injury is correlated with COVID-19 severity, the pattern of glomerular injury is intimately associated with the expression of APOL1 risk variants.

Impact of integrating objective structured clinical examination into academic student assessment: Large-scale experience in a French medical school.

PURPOSE: Objective structured clinical examinations (OSCE) evaluate clinical reasoning, communication skills, and interpersonal behavior during medical education. In France, clinical training has long relied on bedside clinical practice in academic hospitals. The need for a simulated teaching environment has recently emerged, due to the increasing number of students admitted to medical schools, and the necessity of objectively evaluating practical skills. This study aimed at investigating the relationships between OSCE grades and current evaluation modalities. METHODS: Three-hundred seventy-nine 4th-year students of University-of-Paris Medical School participated to the first large-scale OSCE at this institution, consisting in three OSCE stations (OSCE#1-3). OSCE#1 and #2 focused on cardiovascular clinical skills and competence, whereas OSCE#3 focused on relational skills while providing explanations before planned cholecystectomy. We investigated correlations of OSCE grades with multiple choice (MCQ)-based written examinations and evaluations of clinical skills and behavior (during hospital traineeships); OSCE grade distribution; and the impact of integrating OSCE grades into the current evaluation in terms of student ranking. RESULTS: The competence-oriented OSCE#1 and OSCE#2 grades correlated only with MCQ grades (r = 0.19, P<0.001) or traineeship skill grades (r = 0.17, P = 0.001), respectively, and not with traineeship behavior grades (P>0.75). Conversely, the behavior-oriented OSCE#3 grades correlated with traineeship skill and behavior grades (r = 0.19, P<0.001, and r = 0.12, P = 0.032), but not with MCQ grades (P = 0.09). The dispersion of OSCE grades was wider than for MCQ examinations (P<0.001). When OSCE grades were integrated to the final fourth-year grade with an incremental 10%, 20% or 40% coefficient, an increasing proportion of the 379 students had a ranking variation by ±50 ranks (P<0.001). This ranking change mainly affected students among the mid-50% of ranking. CONCLUSION: This large-scale French experience showed that OSCE designed to assess a combination of clinical competence and behavioral skills, increases the discriminatory capacity of current evaluations modalities in French medical schools.

Temporal trends in living kidney donation in France between 2007 and 2017.

BACKGROUND: Long-term studies have demonstrated a slight increased risk for end-stage renal disease (ESRD) for living kidney donors (LKD). In France, living kidney donation doubled within the past 10 years. We investigated the change in characteristics of LKD between 2007 and 2017 and the adequacy of follow-up. METHODS: Data were obtained from the national registry for LKD. We compared characteristics of LKD between two study periods: 2007-11 and 2012-17, and stratified donors by age and relation to recipient. We aggregated four characteristics associated with higher ESRD risk [young age, first-degree relation to recipient, obesity, low glomerular filtration rate (GFR) for age] in a single risk indicator ranging from 0 to 4. RESULTS: We included 3483 donors. The proportion of unrelated donors >56 years of age increased significantly. The proportion of related donors <56 years of age decreased significantly. The body mass index and proportion of obese donors did not change significantly. The proportion of donors with low estimated GFR for age decreased significantly from 5% to 2.2% (P < 0.001). The proportion of donors with adequate follow-up after donation increased from 19.6% to 42.5% (P < 0.001). No donor had a risk indicator equal to 4, and the proportion of donors with a risk indicator equal to 0 increased significantly from 19.2% to 24.9% (P < 0.001). CONCLUSIONS: An increase in living kidney donation in France does not seem to be associated with the selection of donors at higher risk of ESRD and the proportion of donors with adequate annual follow-up significantly increased.

Development and Validation of a Modified Full Age Spectrum Creatinine-Based Equation to Estimate Glomerular Filtration Rate : A Cross-sectional Analysis of Pooled Data.

BACKGROUND: The Chronic Kidney Disease in Children Study (CKiD) equation for children and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for adults are recommended serum creatinine (SCr)-based calculations for estimating glomerular filtration rate (GFR). However, these equations, as well as their combination, have limitations, notably the problem of implausible changes in GFR during the transition from adolescence to adulthood and overestimation of GFR in young adults. The full age spectrum (FAS) equation addresses these issues but overestimates GFR when SCr levels are low. OBJECTIVE: To develop and validate a modified FAS SCr-based equation combining design features of the FAS and CKD-EPI equations. DESIGN: Cross-sectional analysis with separate pooled data sets for development and validation. SETTING: Research and clinical studies (n = 13) with measured GFR available. PATIENTS: 11 251 participants in 7 studies (development and internal validation data sets) and 8378 participants in 6 studies (external validation data set). MEASUREMENTS: Clearance of an exogenous marker (reference method), SCr level, age, sex, and height were used to develop a new equation to estimate GFR. RESULTS: The new European Kidney Function Consortium (EKFC) equation is a FAS equation with low bias (-1.2 mL/min/1.73 m2 [95% CI, -2.7 to 0.0 mL/min/1.73 m2] in children and -0.9 mL/min/1.73 m2 [CI, -1.2 to -0.5 mL/min/1.73 m2] in adults) across the FAS (2 to 90 years) and SCr range (40 to 490 µmol/L [0.45 to 5.54 mg/dL]) and with fewer estimation errors exceeding 30% (6.5% [CI, 3.8% to 9.1%] in children and 3.1% [CI, 2.5% to 3.6%] in adults) compared with the CKiD and CKD-EPI equations. LIMITATION: No Black patients were included. CONCLUSION: The new EKFC equation shows improved accuracy and precision compared with commonly used equations for estimating GFR from SCr levels. PRIMARY FUNDING SOURCE: Swedish Research Council (Vetenskapsrådet).