Prospective urinary albumin/creatinine ratio for diagnosis, staging, and organ response assessment in renal AL amyloidosis: results from a large cohort of patients

Objectives Quantification of 24 h-proteinuria is the gold standard for diagnosing, staging, and monitoring of patients with renal AL amyloidosis. However, 24 h-urine collection is cumbersome and may result in preanalytical error. In this prospective study, we investigated the role of urinary albumin/creatinine ratio (UACR) (cut-off: 300 mg/g) identifying renal involvement, evaluated a UACR-based staging system (UACR cut-off: 3,600 mg/g) and assessed whether UACR response (UACR decrease >30% without worsening in eGFR >25%) predicts renal outcome in 531 patients with newly-diagnosed AL amyloidosis. Methods From October 2013 paired 24 h-proteinuria and UACR (on first morning void) were measured in all newly-diagnosed patients with AL amyloidosis. Correlation between 24 h-proteinuria and UACR at baseline was assessed by Pearson’s r test. Impact of UACR response on renal outcome was assessed in randomly created testing (n=354) and validation (n=177) cohorts. Results A strong linear correlation was found between 24 h-proteinuria and UACR at baseline (r=0.90; p<0.001). After a median follow-up of 31 months, 57 (11%) patients required dialysis. A UACR-based renal staging system identified three stages with significantly higher dialysis rate at 36 months comparing stage I with stage II and stage II with stage III. Achieving a renal response, according to a UACR-based criterion, resulted in lower dialysis rate in both testing and validation cohorts. Conclusions UACR is a reliable marker for diagnosis, prognosis, and organ response assessment in renal AL amyloidosis and can reliably replace 24 h-proteinuria in clinical trials and individual patients’ management.

Peritoneal Dialysis with Rigid Catheters in Children with Acute Kidney Injury: A Single-Centre Experience

Peritoneal dialysis (PD) is a simple and preferred modality of dialysis for children with acute kidney injury (AKI) in resource poor countries. The aim of the study is to evaluate the utility and safety of acute PD using rigid catheter in critically ill children admitted to pediatric intensive care unit (PICU) with emphasis on short-term patient and renal outcome and complications. In this retrospective study, outcome and complications of PD using rigid catheter were evaluated in 113 critically ill children admitted in PICU of a tertiary care hospital from 2014 to 2019. The most common causes for AKI were sepsis (39.8%), dengue infection (16.8%), and hemolytic uremic syndrome (13.2%). In 113 patients, 122 PD catheters were inserted, and the median duration of PD was 60 (IQR: 36–89) hours. At the initiation of PD, 64 (56.6%) patients were critically ill requiring mechanical ventilation and inotropes, 26 (23%) had disseminated intravascular coagulation, and 42 (37%) had multiorgan dysfunction syndrome. PD was effective and there was a significant improvement in urea and creatinine, and one-third patients (n = 38; 33.6%) had complete renal recovery at the end of PD. Total complications were seen in 67% children but majority of them were metabolic (39.8%). Total catheter related complications were seen in 21.2% and peritonitis was seen in 4.4%. Catheter removal due to complications was required in 8.8% children. Overall, among children on PD, 53.7% survived. Acute PD with rigid catheters can be performed bedside in absence of soft catheters and significant clearance can be obtained without major life-threatening complications.

Meta-Analytical Accuracy of ANCA Renal Risk Score for Prediction of Renal Outcome in Patients With ANCA-Associated Glomerulonephritis

Background: To evaluate the diagnostic accuracy of antineutrophil cytoplasmic antibody (ANCA) renal risk score (ARRS) for prediction of renal outcome in patients with ANCA-associated glomerulonephritis (ANCA-GN).Methods: We searched PubMed, EMBASE, Ovid, Web of Science, the Cochrane Library, and ClinicalTrials.gov for studies, which used ARRS to predict end-stage renal disease (ESRD) in patients with ANCA-GN. Two reviewers independently screened articles for inclusion, assessed the quality of studies with both an adapted Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. We calculated the combined patients with ESRD in the ARRS categories and presented the summary and individual estimates based on the ARRS categories. Then, the sensitivity, specificity, diagnostic odds ratio (DOR), positive/negative likelihood ratio, and the area under the receiver operating characteristic (AUROC) curves of the pooled data for ARRS were used to assess the accuracy of the “above the low-risk threshold” (ARRS ≥ 2) and “high-risk grade” (ARRS ≥ 8) for renal outcome of patients with ANCA-GN. The hierarchical summary ROC (HSROC) was used to verify the accuracy value. The clinical utility of ARRS was evaluated by the Fagan plot. Heterogeneity was explored using meta-regression and subgroup analysis.Results: A total of 12 distinct cohorts from 11 articles involving 1,568 patients with ANCA-GN were analyzed. The cumulative patients with ESRD at the maximum follow-up of 60 months was 5% (95% CI: 0.02–0.07; p &lt; 0.001) for ANCA-GN with low ARRS (0–1 points) and significantly increased to 22% (95% CI: 0.15–0.29; p &lt; 0.001) medium ARRS (2–7 points). The combined cumulative patients with ESRD was 59% (95% CI: 0.49–0.69; p &lt; 0.001) high ARRS (8–11 points). The pooled sensitivity of ARRS ≥ 2 in predicting ESRD was 98% with a specificity of 30% and a DOR of 15.08 and the mean AUROC value was 0.82. The pooled sensitivity of ARRS ≥ 8 in predicting ESRD was 58% with a specificity of 86% and a DOR of 7.59. The meta-regression and subgroup analysis indicated that variation in the geographic regions, study design, index risk, follow-up time, age of patient, publication year, and number of patient could be the potential sources of heterogeneity in the diagnosis of ARRS ≥ 8.Conclusion: This meta-analysis emphasized the good performance of the ARRS score in predicting the renal outcome in patients with ANCA-GN. However, these findings should be verified by future large-scale prospective studies.

Proteinuria and serum creatinine after 12 months of treatment for lupus nephritis as predictors of long-term renal outcome: a case–control study

Background Lupus nephritis (LN) is a major source of morbidity and mortality in patients with systemic lupus erythematosus (SLE), with 10–25% of patients progressing to end-stage renal disease (ESRD). Objective This study aims to elucidate the predictive capabilities of 24-h proteinuria (24PTU) and serum creatinine (sCr) after 12 months of treatment with respect to long-term renal outcomes in LN in a single-center cohort of LN patients. Methods A retrospective analysis was performed on 214 patients diagnosed with LN followed in our center. Values of 24PTU and sCr were assessed at baseline and after 3, 6 and 12 months, and after 5 years and/or the last evaluation. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 for 3 months or longer. End-stage renal disease (ESRD) was defined as the need for permanent dialysis. Receiver operating characteristics curves (ROC) were used to test the best cut-off value of 24PTU and sCr at 12 months who predict bad long-term renal outcomes. Results The mean follow-up period was 11.2 ± 7.2 years. The best cut-off values for 24PTU and sCr as predictor of CKD were, respectively, 0.9 g/24 h and 0.9 mg/dL. ROC curve for 24PTU had a slightly lower performance than ROC curve for sCr as predictor for CKD (PTU AUC = 0.68; sCr AUC = 0.70), but sensitivity and specificity were better for 24PTU (24PTU: sensitivity = 63.5%, specificity = 71.2%; sCr: sensitivity = 54.8%, specificity = 75.3%). When the outcome was ESRD the best cut-off points were 0.9 g/24hs and 1.3 mg/dL for 24PTU and sCr, respectively, and the curve performance was better for 24PTU (PTU AUC = 0.72; sCr AUC = 0.61). Conclusions In this ethnically diverse population with LN followed for a long time (> 10 years), levels of 24PTU > 0.9/day at 12 months was a good predictor of bad long-term renal outcome. The serum creatinine > 0.9 mg/dL and > 1.3 mg/dL at 12 months were also good predictors of CKD and ESRD, respectively. Patients with 24PTU < 0.9 g/day and sCr < 1.3 mg/dL at 12 months are not likely to develop ESRD because of the high negative predictive values (NPV) (93.2% and 82%). 24PTU and sCr are relevant as components for a treat-to-target strategy for LN treatment, since their high NPV corroborates their importance as good predictors of long-term renal outcome.

2021 Korean Diabetes Association Clinical Practice Guidelines for Diabetes: Diabetic Kidney Disease

Diabetic kidney disease is one of the most serious complications of type 2 diabetes and a leading cause of end-stage kidney disease. Recently, the Korean Diabetes Association released a new version of clinical practice guidelines including substantial changes in the management of diabetic kidney disease. Of note, sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide-1 receptor agonists are now the preferred glucose-lowering agents for reduced glomerular filtration rate or albuminuria. Convincing evidence from cardiovascular or renal outcome trials supports the recommendation of those drugs. This review summarizes the results of recent clinical studies on diabetic kidney disease and explains new clinical recommendations based on them.

Blocking of inflammatory heparan sulfate domains by specific antibodies is not protective in experimental glomerulonephritis

Glomerulonephritis is an acquired serious glomerular disease, which involves the interplay of many factors such as cytokines, chemokines, inflammatory cells, and heparan sulfate (HS). We previously showed that blocking of inflammatory heparan sulfate domains on cultured glomerular endothelium by specific anti-HS single chain antibodies reduced polymorphonuclear cell (PMN) adhesion and chemokine binding. We hypothesized that injection of anti-HS antibodies in PMN-driven experimental glomerulonephritis should reduce glomerular influx of PMNs and thereby lead to a better renal outcome. In contrast to our hypothesis, co-injection of anti-HS antibodies did not alter the final outcome of anti-glomerular basement membrane (anti-GBM)-induced glomerulonephritis. Glomerular PMN influx, normally peaking 2 hours after induction of glomerulonephritis with anti-GBM IgG was not reduced by co-injection of anti-HS antibodies. Four days after induction of glomerulonephritis, albuminuria, renal function, glomerular hyalinosis and fibrin deposition were similar in mice treated and not treated with anti-HS antibodies. Interestingly, we observed transient effects in mice co-injected with anti-HS antibodies compared to mice that did not receive anti-HS antibodies: (i) a decreased renal function 2 hours and 1 day after induction of glomerulonephritis; (ii) an increased albuminuria after 2 hours and 1 day; (iii) an increased glomerular fibrin deposition after 1 day; (iv) a reduced glomerular macrophage influx after 1 day; (v) a sustained glomerular presence of PMNs at day 1 and 4, accompanied by an increased renal expression of IL-6, CXCL1, ICAM-1, L-selectin, CD11b and NF-κB. The mechanism underlying these observations induced by anti-HS antibodies remains unclear, but may be explained by a temporarily altered glycocalyx and/or altered function of PMNs due to the binding of anti-HS antibodies. Nevertheless, the evaluated anti-HS antibodies do not show therapeutic potential in anti-GBM-induced glomerulonephritis. Future research should evaluate other strategies to target HS domains involved in inflammatory processes during glomerulonephritis.

Urine β2-Microglobulin and Retinol-Binding Protein and Renal Disease Progression in IgA Nephropathy

Background: Tubulointerstitial involvement has been reported to have a decisive influence on the progression of IgA nephropathy (IgAN). High levels of urine β2-microglobulin (β2-MG) and retinol-binding protein (RBP) were observed in patients with IgAN with tubulointerstitial lesions. However, their roles in disease progression remain unclear. This study aimed to evaluate the associations of urine β2-MG and RBP with the progression of IgAN.Methods: We retrospectively investigated a cohort of 2,153 patients with IgAN. Clinical and pathological features, outcomes, and urine β2-MG, and RBP at the time of biopsy were collected. The associations, of urine β2-MG and RBP with the composite renal outcome, defined as a decline in estimated glomerular filtration rate (eGFR) of ≥50% from baseline or end-stage renal disease (ESRD), were examined using restricted cubic splines and the Cox proportional hazards models.Results: During a median follow-up of 20.40 months, 140 (6.50%) patients reached the composite renal outcomes. Restricted cubic splines showed that patients with higher urinary β2-MG and RBP levels had worse renal outcomes. The Cox regression analysis revealed that urine β2-MG and RBP were associated with a risk of the composite renal outcome in the multivariate adjusted model [+1 SD for log β2-MG, hazard ratio (HR) = 1.462, 95% CI: 1.136–1.882, p = 0.003; +1 SD for log RBP, HR = 1.972, 95% CI: 1.486–2.617, p = 0.001]. The associations were detectable within patients with baseline eGFR &lt;90 ml/min/1.73 m2 (+1 SD for log β2-MG, HR = 1.657, 95% CI: 1.260–2.180, p &lt; 0.001; +1 SD for log RBP, HR = 1.618, 95% CI: 1.199–2.183, p = 0.002), but not among patients with eGFR ≥90 ml/min/1.73 m2.Conclusion: Higher levels of urine β2-MG and RBP were independent risk factors for renal disease progression in IgAN.

SGLT-2 inhibitors and cardiorenal outcomes in patients with or without type 2 diabetes: a meta-analysis of 11 CVOTs

Background It has been suggested that sodium–glucose cotransporter 2 (SGLT-2) inhibitors reduce the cardiorenal risk in patients with type 2 diabetes (T2D). The purpose of this study is to provide an update of all large cardiovascular outcome trials (CVOTs) with SGLT-2 inhibitors to assess their cardiorenal efficacy in patients with and without T2D. Methods An electronic search up to 30 September 2021 was conducted in PubMed, EMBASE, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov. to determine eligible trials. We included CVOTs comparing any SGLT-2 inhibitor with placebo, reporting desired cardiovascular or renal outcomes and with a follow-up duration of at least 6 months. Results Eleven CVOTs, with data from five SGLT-2 inhibitors (empagliflozin, canagliflozin, dapagliflozin, ertugliflozin and sotagliflozin) and 77,541 participants, were included. In the overall analysis, the risk of the composite CV mortality or hospitalization for heart failure (HF) was reduced by 23% (HR = 0.77, 95% CI 0.73–0.82, P < 0.001) compared with placebo, with not significant heterogeneity (I2 = 26%, P = 0.20), and irrespective of the presence of T2D (P for interaction = 0.81) and age (> 65 vs ≤ 65 years, P for interaction = 0.78). The risk of CV mortality, total mortality and hospitalization for HF was significantly reduced by 16%, 13%, and 32%, respectively; similarly, the risk of the composite renal outcome was reduced by 35% (HR = 0.65, 95% CI 0.56–0.75), with moderate heterogeneity (I2 = 32%). In the analysis of 6 CVOTs reporting the data, the risk of major cardiovascular events (MACE) was reduced by 12%, with low heterogeneity (I2 = 21.2%, P = 0.19) and irrespective of the presence of established CV disease at baseline (P for interaction = 0.46). Conclusions Therapy with SGLT-2 inhibitors in patients with cardiometabolic and renal diseases results in a sustained to moderate reduction of the composite CV death or hospitalization for HF, robust reduction of HF and renal outcomes, moderate reduction of CV mortality, total mortality and MACE.