Enhancing vascular access planning in CKD: validating the 40% KFRE threshold for predicting ESKD in a French retrospective cohort study.

Background: Establishing the optimal timing for creating vascular access in patients with chronic kidney disease (CKD) is a critical and challenging aspect of patient management. The Kidney Disease: Improving Global Outcomes guidelines propose using a 40% 2-year threshold based on the Kidney Failure Risk Equation (KFRE) for this purpose. However, the effectiveness of this threshold compared with traditional methods, such as estimated glomerular filtration rate (eGFR), is not well-established. Methods: In this monocentric retrospective cohort study, we analyzed data from patients referred for vascular mapping before arteriovenous fistula (AVF) creation between April 2013 and June 2023. The study aimed to compare the ≥40% 2-year KFRE threshold with a <15 mL/min/1.73 m² eGFR threshold for predicting end-stage kidney disease (ESKD). We assessed the probability of ESKD, considering death before AVF creation as a competing risk. Discrimination between KFRE and eGFR was evaluated using C-statistics. Results: The study included 238 patients with a mean age of 65.2 years and a mean eGFR of 13.3 mL/min/1.73 m². Over a median follow-up of 10.7 months, 178 patients developed ESKD, and 21 died before ESKD. Probability of ESKD at 1 year was 77.6% (95% CI 69.9%-85.3%) using a ≥40% 4-variable KFRE threshold versus 65.8% (95% CI 58.3%-73.3%) using a <15 mL/min/1.73 m² eGFR threshold. The C-statistics indicated better predictive ability for the 8-variable KFRE at 6 months [0.82 (95% CI 0.76-0.88)], while both 4- and 8-variable KFRE models were effective for 1-year predictions [0.835 (95% CI 0.78-0.89) and 0.82 (95% CI 0.76-0.875), respectively]. Sensitivity and specificity analyses favored the ≥40% KFRE threshold over the eGFR threshold. Conclusions: This study suggests that using a ≥40% 2-year KFRE threshold for planning vascular access in CKD patients is promising and potentially superior to the traditional <15 mL/min/1.73 m² eGFR threshold. This approach may offer a balance between minimizing premature AVF creation and the risk of starting dialysis via a central venous catheter.

Effects of high- vs low-dose native vitamin D on albuminuria and the renin-angiotensin-aldosterone system: a randomized pilot study.

BACKGROUND: Residual albuminuria is associated with an increased risk of progression to ESKD. We tested whether a supplementation with native vitamin D could reduce albuminuria in stable CKD patients under maximal renin-angiotensin system (RAS) blockade. METHODS: We conducted a randomized controlled study of high (cholecalciferol 100 000 UI per 10 days over 1 month) vs low-dose (ergocalciferol 400 UI/days over 1 month) supplementation with native vitamin D on urinary albumin/creatinine ratio, blood pressure and the RAS over 1 month in stable CKD patients with albuminuria and maximum tolerated RAS blockade. RESULTS: We included 31 patients, 21 in the high dose group and 10 in the low dose group. In contrast with a low dose, high dose vitamin D normalized plasma 25(OH)D, decreased iPTH but slightly increased plasma phosphate. High dose vitamin D decreased geometric mean UACR from 99.8 mg/mmol (CI 95% 60.4-165.1) to 84.7 mg/mmol (CI 95% 51.7-138.8, p = 0.046). In the low dose group, the change in geometric mean UACR was not significant. Blood pressure, urinary 24 h aldosterone and peaks and AUC of active renin concentrations after acute stimulation by a single dose of 100 mg captopril were unaffected by the supplementation in native vitamin D, irrespective of the dose. Native vitamin D supplementation was well tolerated. CONCLUSIONS: We found a small (- 15%) but significant decrease in albuminuria after high dose vitamin D supplementation. We found no effect of vitamin D repletion on blood pressure and the systemic RAS, concordant with recent clinical studies.

Evaluation of a predictive model of end-stage kidney disease in a French-based cohort.

BACKGROUND: The risk of ESKD is highly heterogeneous among renal diseases, and risk scores were developed to account for multiple progression factors. Kidney failure risk equation (KFRE) is the most widely accepted, although external validation is scarce. The objective of this study was to evaluate the usefulness of this score in a French case-control cohort and test the pertinence of the proposed thresholds. METHODS: A retrospective case-control study comparing a group of patients starting renal replacement therapy (RRT) to a group of patients with CKD stages 3-5. Multivariate analysis to assess the predictors of ESKD risk. Discrimination of 4-, 6- and 8-variable scores using ROC curves and compared with eGFR alone and albumin/creatinine ratio (ACR) alone. RESULTS: 314 patients with a ratio of 1 case for 1 control. In multivariate analysis, increasing age and higher eGFR were associated with a lower risk of ESKD (OR 0.62, 95% CI 0.48-0.79; and OR 0.72, 95% CI 0.59-0.86, respectively). The log-transformed ACR was associated with a higher risk of ESKD (OR 1.25 per log unit, 95% CI 1.02-1.55). The 4-variable score was significantly higher in the RRT group than in the CKD-ND group, and was more efficient than the eGFR (AUROC 0.66, 95% CI 0.60-0.72, p = 0.018) and the log-transformed ACR (AUROC 0.63 95% CI 0.60-0.72, p = 0.0087) to predict ESKD. The 6-variable score including BP metrics and diabetes was not more discriminant as the 4-variable score. The 8-variable score had similar performance compared with the 4-score (AUROC 8-variable score: 0.70, 95% CI 0.64-0.76, p = 0.526). A 40% and 20% score thresholds were not superior to eGFR < 15 and 20 mL/min/1.73 m2, respectively. A 10% threshold was more specific than an eGFR < 30 mL/min/1.73 m2. CONCLUSION: KFRE was highly discriminant between patients progressing to ESKD vs those non-progressing. The 4-variable score may help stratify renal risk and referral in the numerous patients with stage 3 CKD. Conversely, the proposed thresholds for creating vascular access or preemptive transplantation were not superior to eGFR alone.