External validation of the KFRE and Grams prediction models for kidney failure and death in a Spanish cohort of patients with advanced chronic kidney disease.

BACKGROUND: The Kidney Failure Risk Equation (KFRE) is a 2- and 5-year kidney failure prediction model that is applied in chronic kidney disease (CKD) G3 + . The Grams model predicts kidney failure and death at 2 and 4 years in CKD G4 + . There are limited external validations of the Grams model, especially for predicting mortality before kidney failure. METHODS: We performed an external validation of the Grams and Kidney Failure Risk Equation prediction models in incident patients with CKD G4 + at Hospital Universitario Fundación Alcorcón, Spain, between 1/1/2014 and 31/12/2018, ending follow-up on 30/09/2023. Discrimination was performed calculating the area under the receiver-operating characteristic curve. Calibration was assessed using the Hosmer-Lemeshow test and the Brier score. RESULTS: The study included 339 patients (mean age 72.2 ± 12.7 years and baseline estimated glomerular filtration rate 20.6 ± 5.0 ml/min). Both models showed excellent discrimination. The area under the curve (AUC) for Kidney Failure Risk Equation-2 and Grams-2 were 0.894 (95% CI 0.857-0.931) and 0.897 (95%CI 0.859-0.935), respectively. For Grams-4 the AUC was 0.841 (95%CI 0.798-0.883), and for Kidney Failure Risk Equation-5 it was 0.823 (95% CI 0.779-0.867). For death before kidney failure, the Grams model showed acceptable discrimination (AUC 0.708 (95% CI 0.626-0.790) and 0.744 (95% CI 0.683-0.804) for Grams-2 and Grams-4, respectively). Both models presented excellent calibration for predicting kidney failure. Grams model calibration to estimate mortality before kidney failure was also excellent. In all cases, Hosmer-Lemeshow test resulted in a p-value greater than 0.05, and the Brier score was less than 0.20. CONCLUSIONS: In a cohort of patients with CKD G4 + from southern Europe, both the Grams and Kidney Failure Risk Equation models are accurate in estimating the risk of kidney failure. Additionally, the Grams model provides a reliable estimate of the risk of mortality before kidney failure.

Humoral Response Following Triple Dose of mRNA Vaccines Against SARS-CoV-2 in Hemodialysis Patients: Results After 1 Year of Follow-Up.

Introduction: COVID-19 is associated with an increased mortality in hemodialysis patients. Therefore, achieving a long-lasting effective immune response to SARS-CoV-2 vaccines is essential. This study describes the humoral immune response in hemodialysis patients following three doses of mRNA vaccines against SARS-CoV-2, and explores the factors associated with a sustained immune response. Materials and Methods: We analyzed the monthly serological evolution of SARS-CoV-2 anti-S(RBD) antibodies for 1 year in 178 chronic hemodialysis patients who received three doses of SARS-CoV-2 mRNA vaccines. The primary outcome was sustained effective humoral response defined as anti-S(RBD) levels > 1,000 AU/ml after 4 months from the third dose. Multivariate logistic regression analyses were used to identify features associated with a sustained humoral immune response. Results: After the initial two SARS-CoV-2 mRNA vaccine doses, 77.8% of patients showed an immediate effective humoral response, decreasing to 52.5% after 4 months. Antibody levels were significantly higher in COVID-exposed patients and HBV vaccine responders. After the third dose, 97% of patients showed an effective humoral response, and remained in 91.7% after 4 months. The mean monthly rate of antibody titer decline decreased from 33 ± 14.5 to 25 ± 16.7%. Multivariate regression analysis showed that previous exposure to COVID-19 and response to HBV vaccines were associated with an effective sustained humoral immune response. Conclusion: Immunization with SARS-CoV-2 mRNA vaccines elicits an effective immediate humoral immune response in hemodialysis patients, with a progressive waning in antibody levels. A third booster dose enhances the immune response with significantly higher antibody levels and more sustained humoral immune response. COVID-naïve patients and patients without previous response to HBV vaccines are likely to benefit from receiving more booster doses to maintain an effective immune response.

Late thrombotic complications after SARS-CoV-2 infection in hemodialysis patients.

INTRODUCTION: There is an increased risk of thrombotic complications in patients with COVID-19. Hemodialysis patients are already at an increased risk for thromboembolic events such as stroke and pulmonary embolism. The aim of our study was to determine the incidence of late thrombotic complications (deep vein thrombosis, pulmonary embolism, stroke, new-onset vascular access thrombosis) in maintenance hemodialysis patients after recovery from COVID-19. METHODS: We performed a retrospective cohort study of 200 prevalent hemodialysis patients in our center at the start of the pandemic. We excluded incident patients after the cohort entry date and those who required hemodialysis for acute kidney injury, and excluded patients with less than 1 month follow-up due to kidney transplantation or death from non-thrombotic causes. FINDINGS: One-hundred and eighty five prevalent hemodialysis patients finally met the inclusion criteria; 37 patients (17.6%) had SARS-CoV-2 infection, out of which 10 (27%) died during the acute phase of disease without evidence of thrombotic events. There was an increased risk of thrombotic events in COVID-19 survivors compared to the non-infected cohort (18.5% vs. 1.9%, p = 0.002) after a median follow-up of 7 months. Multivariate regression analysis showed that COVID-19 infection increased risk for late thrombotic events adjusted for age, sex, hypertension, diabetes, antithrombotic treatment, and previous thrombotic events (Odds Ratio (OR) 26.4, 95% confidence interval 2.5-280.6, p = 0.01). Clinical and laboratory markers did not predict thrombotic events. CONCLUSIONS: There is an increased risk of late thrombotic complications in hemodialysis patients after infection with COVID-19. Further studies should evaluate the benefit of prolonged prophylactic anticoagulation in hemodialysis patients after recovery from COVID-19.

Dialysis arteriovenous access monitoring and surveillance according to the 2017 Spanish Guidelines.

The Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology (S.E.N.), vascular surgery (SEACV), interventional radiology (SERAM-SERVEI), infectious diseases (SEIMC), and nephrology nursing (SEDEN)), along with the methodological support of the Iberoamerican Cochrane Centre, has developed the Spanish Clinical Guidelines on Vascular Access for Hemodialysis. This article summarizes the main issues from the guideline's chapter entitled "Monitoring and surveillance of arteriovenous access." We will analyze the current evidence on conflicting topics such as the value of the flow-based screening methods for the arteriovenous access surveillance or the role of Doppler ultrasound as the imaging exploration to confirm suspected stenosis. In addition, the concept of significant stenosis and the criteria to perform the elective intervention for stenosis were reviewed. The adoption of these guidelines will hopefully translate into a reduced risk of thrombosis and increased patency rates for both arteriovenous fistulas and grafts.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis. / Guía Clínica Española del Acceso Vascular para Hemodiálisis.

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Kidney injury after sodium phosphate solution beyond the acute renal failure.

BACKGROUND AND OBJECTIVES: Screening colonoscopy with polipectomy reduces colonorectal cancer incidence and mortality. An adequate bowel cleansing is one of the keys to achieving best results with this technique. Oral sodium phosphate solution (OSP) had a widespread use in the 90s decade. Its efficacy was similar to polyethylene glycol (PEG) solution, but with less cost and convenient administration. Series of patients with acute renal failure due to OSP use have been reported. However, large cohorts of patients found no difference in the incidence of renal damage between these two solutions. METHODS: From 2006 to 2009 we identified twelve cases of phosphate nephropathy after colonoscopy prepared with OSP. All patients were followed up to six months. All patients had received just a single dose. RESULTS: We analyzed 12 cases with phosphate nephropathy; three patients debuted with AKI and nine patients had chronic renal injury. Four cases were confirmed with renal biopsy. One patient with AKI needed hemodialysis at diagnosis without subsequent recovery. Two patients (both with chronic damage) fully recovered their previous renal function. The remaining patients (nine) had an average loss of estimated glomerular filtration rate of 24ml/min/1.73m(2). CONCLUSIONS: The use of OSP can lead to both acute and chronic renal damage. However, chronic injury was the most common pattern. Both forms of presentation imply a significant and irreversible loss of renal function. Further studies analyzing renal damage secondary to bowel cleaning should consider these two different patterns of injury.

What is the optimal level of vitamin D in non-dialysis chronic kidney disease population?

AIM: To evaluate thresholds for serum 25(OH)D concentrations in relation to death, kidney progression and hospitalization in non-dialysis chronic kidney disease (CKD) population. METHODS: Four hundred and seventy non-dialysis 3-5 stage CKD patients participating in OSERCE-2 study, a prospective, multicenter, cohort study, were prospectively evaluated and categorized into 3 groups according to 25(OH)D levels at enrollment (less than 20 ng/mL, between 20 and 29 ng/mL, and at or above 30 ng/mL), considering 25(OH)D between 20 and 29 ng/mL as reference group. Association between 25(OH)D levels and death (primary outcome), and time to first hospitalization and renal progression (secondary outcomes) over a 3-year follow-up, were assessed by Kaplan-Meier survival curves and Cox-proportional hazard models. To identify 25(OH)D levels at highest risk for outcomes, receiver operating characteristic (ROC) curves were performed. RESULTS: Over 29 ± 12 mo of follow-up, 46 (10%) patients dead, 156 (33%) showed kidney progression, and 126 (27%) were hospitalized. After multivariate adjustment, 25(OH)D < 20 ng/mL was an independent predictor of all-cause mortality (HR = 2.33; 95%CI: 1.10-4.91; P = 0.027) and kidney progression (HR = 2.46; 95%CI: 1.63-3.71; P < 0.001), whereas the group with 25(OH)D at or above 30 ng/mL did not have a different hazard for outcomes from the reference group. Hospitalization outcomes were predicted by 25(OH) levels (HR = 0.98; 95%CI: 0.96-1.00; P = 0.027) in the unadjusted Cox proportional hazards model, but not after multivariate adjusting. ROC curves identified 25(OH)D levels at highest risk for death, kidney progression, and hospitalization, at 17.4 ng/mL [area under the curve (AUC) = 0.60; 95%CI: 0.52-0.69; P = 0.027], 18.6 ng/mL (AUC = 0.65; 95%CI: 0.60-0.71; P < 0.001), and 19.0 ng/mL (AUC = 0.56; 95%CI: 0.50-0.62; P = 0.048), respectively. CONCLUSION: 25(OH)D < 20 ng/mL was an independent predictor of death and progression in patients with stage 3-5 CKD, with no additional benefits when patients reached the levels at or above 30 ng/mL suggested as optimal by CKD guidelines.

Economic repercussions of implementing a protocol for urgent surgical repair of thrombosed arteriovenous fistulae.

INTRODUCTION: When a patient undergoing haemodialysis suffers from arteriovenous fistula (AVF) thrombosis, (s)he needs an urgent procedure before the next dialysis session. Two different treatment options are available: placing a central venous catheter (CVC) or repairing the AVF. The objective of this study is to assess the possibility of urgent repair of thrombosed AVFs within the emergency care activity of a general surgery department and to determine the possible economic repercussions of implementing this working protocol in an area of healthcare. METHOD: We completed the prospective collection of all the urgent surgical interventions made to repair thrombosed AVFs for the period 2000-2011 at our centre. The clinical results were analysed using two variables: rate of thrombosis (episodes/patient/year) and percentage of recovery. Recovery was deemed effective if after the surgery the patient was able to undergo dialysis of his/her AVF without the need to place a CVC. The "thrombosed AVF" clinical process was defined and implemented, and its economic cost was analysed via a detailed analysis conducted by our centre's Financial Department. This analysis was also conducted for the alternative clinical process (new AVF), using the data published by the Ministry of Health (weight of the Diagnosis-Related Group: vascular accesses for haemodialysis, hospital complexity unit, public cost of outpatient procedures and percentage of economic repercussions of the implementation of this process, comparing the costs of both procedures). RESULTS: During the study period 268 episodes of thrombosis occurred, a rate of 0.1 episodes/patient/year (0.05 on autologous AVFs and 0.43 on grafts). 203 (75%) were treated urgently by the surgery department, of which 168 AVFs (82%) were recovered. The cost of urgently repairing an AVF was estimated at €999. The average cost of a scheduled AVF intervention, plus the cost of placing and maintaining a CVC, was estimated at €6,397. The saving made by urgent repair of AVFs in our area of healthcare is €107,940/year. Extrapolating this to the entire country for a population of 23,000 patients on haemodialysis, the total would be €9,930,480/year. CONCLUSIONS: It is possible to perform urgent surgical recovery on the majority of AVFs for haemodialysis. Implementing multidisciplinary protocol avoids fitting these patients with catheters, reducing the cost this entails.

Multidisciplinary approach to hemodialysis graft dysfunction and thrombosis.

PURPOSE: Top analize the clinic results of the implantation of a multidisciplinary protocol to maintain permeability of the arteriovenous hemodialysis grafts (AVG). METHOD: Prospective recording of all interventions (radiological and surgical) on AVG dysfunction in the 1999-2007 period. The AVG stenosis were always treated by percutaneous angioplasty (PA) except stenosis recurrence in less than three months or persistence after PA. The AVG thromboses were always treated by surgical thrombectomy plus PTFE bridge if necessary. Complications, primary and secondary AVG patency were reviewed. RESULTS: Ninety six dysfunction AVG were collected for study. All of them were 6x40 mm standard wall PTFE (Gore-Tex®). Thirty six of them were humero-basilic antebraquial loop and sixty were humero-axillary upper arm curve configuration. During the study, 52 PTFE bridges, 109 surgical thrombectomies, 131 PA, and 15 stents were needed to maintain FAVP permeability. Primay patency was 73.68%, 60.21% and 37.52% at one, two and three years respectively. Secondary patency was 89.49%, 84.07% and 66.84% at one, two and three years respectively. We avoid a central venous catheter (CVC) in the 80% of intervention for thrombosis dysfunction. No surgical or radiological related deaths occurred. Median hospital admission related with AVG thrombosis was 0.03/patient/year. CONCLUSION: The application of a combined protocol for the treatment of AVG dysfunction and thrombosis, according to DOQI recomendations obtains good results in AVG patency in our experience.

Course of vascular access and relationship with treatment of anemia.

BACKGROUND AND OBJECTIVES: Maintenance of the vascular access is a crucial factor in hemodialysis, but large studies of factors that are predictive of thrombosis are lacking. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This prospective, multicenter study investigated a cohort to describe the management of vascular access and establish the influence of anemia as a risk factor. The cohort included 1710 patients (aged 64.4 yr; 60% men) who were followed every 3 mo at 119 centers during 12 mo. On inclusion, 9.6% had a catheter, 80.3% had a native arteriovenous fistula, and 10.1% had a polytetrafluoroethylene graft. RESULTS: Low baseline hemoglobin increased the risk for vascular access events. The risk was higher with a polytetrafluoroethylene graft and a catheter versus arteriovenous fistula. The multivariate model included type of vascular access, previous cardiovascular events, and noncorrected anemia. The likelihood of remaining free of vascular access events 12 mo later was 0.727 (baseline hemoglobin <10.0 g/dl), 0.801 (10.01 to 11.0 g/dl), 0.814 (11.01 to 12.0 g/dl), and 0.833 (>12.0 g/dl), figures similar to those obtained with hemoglobin from the trimester before the event. The Cox model included type of vascular access. CONCLUSIONS: Correcting anemia did not increase the risk for vascular access-related events, and anemia that was resistant to treatment identified a subgroup of patients with higher comorbidity and higher likelihood of a vascular access event.

[Definition of processes and indicators for the management of vascular accesses for hemodialysis]. / Definición de procesos e indicadores para la gestión de accesos vasculares para hemodiálisis.

INTRODUCTION: The prevalence of renal replacement therapy has increased, affecting 885 patients per million inhabitants. More than 50% of these patients require hemodialysis with permanent vascular access. In our center a multidisciplinary group was organized to manage processes related to vascular access for hemodialysis. OBJECTIVES: To define processes for the management of vascular access for hemodialysis and to evaluate these processes. MATERIAL AND METHOD: Setting. Level III hospital in the autonomous community of Madrid serving 485,000 inhabitants. STUDY PERIOD: 2002-2004. METHODOLOGY: A multidisciplinary working group was set up. The three most frequent processes were defined and described. Flow charts were used for graphical representation. Quality criteria and indicators were defined with prospective monitoring of electronic medical records, design of a specific surgical protocol, and retrospective analysis. RESULTS: Comparison of the results with the literature. First vascular access. The percentage of patients with arteriovenous fistulas on starting hemodialysis. Percentage of prevalent patients with venous access (autologous fistula, prosthetic device, catheter). Maintenance of access: Rate of thrombosis in autologous-prosthetic arteriovenous fistulas. Percentage of rescued arteriovenous fistulas after thrombosis. Rate of temporary catheters. Resource management. Percentage of ambulatory interventions. Rate of admissions related to arteriovenous fistulas. CONCLUSIONS: Arteriovenous fistulas are the main source of morbidity and hospital admission in patients with chronic renal failure in hemodialysis programs. Multidisciplinary management achieves results above the standards described in the literature. There do not appear to be other determining factors for these results, since the technical procedures performed do not differ from those described in the literature.