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BACKGROUND AND AIMS Among patients with chronic kidney disease, the incidence and prevalence of nonvalvular atrial fibrillation (NVAF) increases as renal function decreases, detecting a prevalence of up to 27% in hemodialysis patients. However, its prevalence among patients on peritoneal dialysis (PD) has been less studied. The aim of the study is to analyse the prevalence of NVAF and characteristics related to its management in PD patients older than 18 years. METHOD An observational, cross-sectional, multicenter and retrospective study was carried out through a survey and request for variables sent through a Google questionnaire to PD units in our country. A total of 1403 patients from 30 PD units were included. RESULTS The mean prevalence of NVAF in the study was 13.2%, median 11.7% (interquartile range: 6.1–19.4). A total of 60% of the centers had a prevalence >10%. A total of 57.6% (n = 17) used the CHADS2 or CHAS2-VASC score to calculate the risk of stroke/thromboembolism in their patients with NVAF. A total of 43.3% (n = 13) do not use it. In these cases, 15.3% (n = 2) do not calculate it because they treat all patients with NVAF and the remaining 84.6% (n = 11) do not use it because the cardiologist uses it and delegates it to them. Regarding the decision to start anticoagulant treatment in NVAF: in 60% of the centers (n = 18) the cardiologist indicates anticoagulation, in 36.7% (n = 11) the indication is made jointly (cardiologist and nephrologist) and only in 3.3% (n = 1) the indication is made by the nephrologist. A total of 72.5% of the patients with NVAF (135/186) received anticoagulant treatment. Of these, 28 (20.7%) received direct-acting anticoagulants and 107 (79.3%) received acenocoumarol. Among direct-acting anticoagulants, the most frequent regimens were: apixaban 2.5 mg/12 h (86%), and edoxaban 30 mg/24 h (7%). A total of 5.9% (11/186) of patients with NVAF did not receive anticoagulant or antiplatelet treatment. A total of 90% of the centers (n = 27) are familiar with the technique of percutaneous appendage closure for the treatment of NVAF, but it is not available in five of them. This technique has been performed in 17 of the patients with NVAF. CONCLUSION The prevalence of NVAF in PD patients is high. The management of these patients is carried out mainly by cardiologists with little participation of nephrologists. Most patients receive anticoagulant treatment with coumarin drugs. The data from this analysis, as well as the limited data from the literature, indicate that an adequate format, a consensus document, as well as more data from observational studies (and especially from randomized controlled trials) are needed to adequately address this common complication in patients with DP.

BACKGROUND AND AIMS The success of peritoneal dialysis (PD) depends on the integrity of the peritoneal membrane. The most common peritoneal functional alteration is an impaired ultrafiltration caused by fast peritoneal solute transfer rate. This situation can be present at start of PD and compromise the durability of the membrane through the stay on PD. If the patient leaves PD for another reason, as in the case of a kidney transplant, it affects the probability of a membrane dysfunction appearance. It is known as a competitive event. The aim of this study was to determine whether baseline peritoneal transport status was a risk factor of mortality and technique failure in a cohort of Spanish PD patients using a statistical competing risk model. METHOD The multicenter retrospective cohort study included adult patients of the Levante Registry PD Work Group in Spain who started PD between February 1993 and June 2020. All patients needed to have a peritoneal equilibration test (PET) performed within the first 6 months after PD start. Patients were followed until technique failure, transplantation, renal function recovery, death, or until September 2020. Peritoneal transport status was considered both as a continuous (D/PCr4h) and as a categorical variable, according to the four groupings of D/PCr values defined by Twardoski. We analysed the effect of peritoneal transport over mortality, peritonitis and technique failure by a competing risk model. Kidney transplantation and renal function recovery were considered competing events. RESULTS A total of 4848 patients were enrolled. Baseline PET measurements were available in 2.307 (47.6%). The median follow-up time was 22.2 months (IQR 11.5–40.5). The main characteristics according to the peritoneal transport status are summarized in Table 1. When peritoneal membrane transport was analysed as a continuous variable, D/PCr was an independent risk factor of technique failure. The hazard ratio subdistribution for technique failure was 1.08 [(1.01; 1.16), P-value = 0.018] for every 0.1 increase in D/P Cr ratio. This effect disappeared when the use of icodextrin was included in the model. Baseline peritoneal transport was not associated with a higher mortality or peritonitis risk. CONCLUSION Basal peritoneal transport rate is an independent risk factor for death-censored technique failure in the Levante DP incident population. The use of icodextrin in these patients seems to mitigate this negative effect and may improve the outcomes in PD in patients with initial fast transport. Conventional methods for survival analysis ignoring the competing events may be inappropriate this cohort of patients.

Background Little is known regarding the dynamics of antibody and T-cell responses in chronic kidney disease (CKD) following coronavirus disease 2019 (COVID-19) vaccination. Methods Prospective observational cohort study including 144 participants on haemodialysis (HD) (n = 52) or peritoneal dialysis (PD) (n = 14), those undergoing kidney transplantation (KT) (n = 30) or those with advanced CKD (ACKD) not on dialysis and healthy controls (n = 18). Anti-Spike (S) antibody and T-cell responses were assessed at 15 days (15D) and 3 months (3M) after complete vaccination schedule. HD, PD and KT patients received mRNA vaccines (mRNA-123 and BNT162b2). Most ACKD patients received BNT162b2 (n = 23), or Ad26.COV.2.S (4). Most controls received BNT162b2 (n = 12), or Ad26.COV.2.S (n = 5). Results Anti-S antibodies at 15D and 3M were detectable in 95% (48/50)/98% (49/50) of HD patients, 93% (13/14)/100% of PD patients, 67% (17/26)/75% (21/28) of KT patients and 96% (25/26)/100% (24/24) of ACKD patients. Rates for healthy controls were 81% (13/16)/100% (17/17). Previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2-S) infection was documented in four (7.7%) HD patients, two (14.3%) PD patients, two (6.7%) KT patients, one (5.55%) healthy control and in no ACKD patient. Antibody levels decreased at 3M in HD (P = .04), PD (P = .008) and ACKD patients (P = .0009). In KT patients, levels increased (P = .04) between 15D and 3M, although they were low at both time points. T-cell responses were detected in HD patients in 37 (80%) at baseline, 35 (70%) at 15D and 41 (91%) at 3M. In PD patients, T-cell responses appeared in 8 (67%) at baseline, 13 (93%) at 15D and 9 (100%) at 3M. In KT patients, T-cell responses were detected in 12 (41%) at baseline, 22 (84%) at 15D and 25 (96%) at 3M. In ACKD patients, T-cell responses were detected in 13 (46%) at baseline, 20 (80%) at 15D and 17 (89%) at 3M. None of healthy controls showed T-cell response at baseline, 10 (67%) at 15D and 8 (89%) at 3M. Conclusions Most HD, PD and ACKD patients develop SARS-CoV-2-S antibody responses comparable to that of healthy controls, in contrast to KT recipients. Antibody waning at 3M was faster in HD, PD and ACKD patients. No differences in SARS-CoV-2 T-cell immunity responses were noticed across study groups.

Background Abnormalities of bone mineral parameters are associated with increased mortality in patients on dialysis, but their effects and the optimal range of these biomarkers are less well characterized in non-dialysis chronic kidney disease (CKD). Methods PECERA (Collaborative Study Project in Patients with Advanced CKD) is a 3-year, prospective multicenter, open-cohort study of 966 adult patients with non-dialyzed CKD stages 4-5 enrolled from 12 centers in Spain. Associations between levels of serum calcium (Ca) (corrected for albumin), phosphate (P), and intact parathyroid hormone (iPTH) with all-cause mortality (primary outcome) and cardiovascular mortality (secondary outcome) were examined using time-dependent Cox proportional hazards models and penalized splines analysis adjusted by demographics and comorbidities, treatments and biochemical values collected every 6 months for 3 years. Results After a median follow-up of 29 months (IQR: 13-36 months) there were 181 deaths (19%). The association of calcium with all-cause mortality was J-shaped, with an increased risk for all-cause mortality at levels > 10.5 mg/dL. For phosphate and iPTH levels, the association was U-shaped. The serum values associated with the minimum risk of mortality were 3.8 mg/dL for phosphate and 70 pg/mL for iPTH, being the lowest risk ranges between 2.8 and 5.0 mg/dL, and between 38 and 112 pg/mL for phosphate and iPTH, respectively. Conclusions Our study provides evidence on the non-linear association of serum calcium, phosphate and iPTH levels with mortality in stage 4 and 5 CKD patients, and suggests potential survival benefits for controlling bone mineral parameters in this population, as previously reported for dialysis patients.

There is a growing interest in the potential role of adipose tissues in cardiac and renal pathophysiology, and determining the mechanisms by which fat compartments around the heart and kidneys influence cardiovascular disease is of clinical importance in both general and high-risk populations. Epicardial fat and perirenal fat have been associated with adverse outcomes in chronic kidney disease (CKD) patients. Epicardial fat is a rich source of free fatty acids and is capable of secreting inflammatory and pro-atherogenic cytokines that promote atherosclerosis through a local paracrine effect. Recent evidence has demonstrated that perirenal fat has a closer correlation with kidney diseases than other visceral fat deposits in obesity or metabolic disturbances. Moreover, perirenal fat has been reported as an independent risk factor for CKD progression and even associated with cardiorenal dysfunction. Accordingly, these forms of organ-specific fat deposits may act as a connecter between vascular and cardiorenal disease. This review explores the possible links between epicardial and perirenal fat and its significant role as a modulator of cardiorenal dysfunction in CKD patients.

Background Hyperkalaemia is a common condition in patients with comorbidities such as chronic kidney disease (CKD) or congestive heart failure (HF). Moreover, severe hyperkalaemia is a potentially life-threatening condition that is associated with a higher risk of adverse clinical events such as ventricular arrhythmias and sudden cardiac death. Currently, data regarding the prognostic implications of chronic hyperkalaemia are available; however, information about the long-term clinical consequences after an episode of severe hyperkalaemia remains scarce. The objective of this study was to evaluate the association between the trajectory of potassium measurements in patients with acute hyperkalaemia and long-term all-cause mortality. Methods This is a retrospective observational study that included patients with acute severe hyperkalaemia [potassium (K) >6 mEq/L] without haemolysis in the emergency room of Dr Peset University Hospital in Valencia, Spain searching the lab database from January 2016 to March 2017. The multivariable-adjusted association of serum potassium with mortality was assessed by using comprehensive state-of-the-art regression methods that can accommodate time-dependent exposure modelling. Results We found 172 episodes of acute hyperkalaemia in 160 patients in the emergency room. The mean ± standard deviation age of the sample was 77 ± 12 years and 60.5% were males. The most frequent comorbidities were CKD (71.2%), HF (35%) and diabetes mellitus (56.9%). Only 11.9% of the patients were on chronic dialysis. A quarter of the patients did not have previous CKD, making hyperkalaemia an unpredictable life-threatening complication. During the acute episode, mean potassium and estimated glomerular filtration rate (eGFR) were 6.6 ± 0.6 (range 6.1–9.2) mEq/L and 23 ± 16 (range 2–84) mL/min/1.73 m2, respectively. After a median (interquartile range) follow-up of 17.3 (2.2–23.7) months, 68 patients died (42.5%). Recurrences of hyperkalaemia (K >5.5 mEq/L) were detected in 39.5% of the patients who were monitored during follow-up. We found that previous potassium levels during an acute severe hyperkalaemia episode were not predictors of mortality. Conversely, the post-discharge longitudinal trajectories of potassium were able to predict all-cause mortality (overall P = 0.0015). The effect of transitioning from hyperkalaemia to normokalaemia (K >5.5 mEq/L to K ≤5.5 mEq/L) after the acute episode was significant, and inversely associated with the risk of mortality. Conclusions Potassium levels prior to a severe hyperkalaemic event do not predict mortality. Conversely, following an episode of acute severe hyperkalaemia, serial kinetics of potassium trajectories predict the risk of death. Further evidence is needed to confirm these findings and clarify the optimal long-term management of these patients.

Background and Aims Few studies have analyzed early lesions of diabetic nephropathy (DN) in those patients who do not have clinical signs of this involvement, since the indication of renal biopsy is usually performed in patients with significant renal manifestations.The aim of the study was to analyze renal histological lesions from autopsies of diabetic patients with or without clinical expression of DN. Thus, we analyze their correlation according to the presence or absence of proteinuria (albumin/creatinine to ratio > 300). Autopsies from non-diabetic patients was used as a control group. Method Kidneys from autopsies of 21 patients with type 2 diabetes mellitus (T2DM) and 4 non-diabetic controls were analyzed by two pathologists. The histological lesions score of DN was performed according to the classification of Tervaert et al. (JASN. 2010; 21: 556–63), and a description of histological findings, clinical and analytical data were made. Results The mean glomeruli per sample was: 170 ±88. Patient demographics of autopsies: mean age 76 ± 11 years, mean duration of diabetes 6.08 ± 3.2 years (20%> 10 years). Last known eGFR: 51 ± 28, HbA1c: 7.3 ± 1.9%. Albuminuria and cardiovascular disease were present in 42% and 60% of patients with T2DM. Histological and clinical data are shown in Table and Graphics. Conclusion A high percentage of diabetics without early clinical lesions of DN (albuminuria) already express moderate to severe histological changes, especially severe mesangial expansion and severe glomerular vascular lesions. The control group showed minimal histological lesions except for mild expansion of the mesangium and inflammation associated with IFTA. Our data suggest renal involvement in T2DM is present in earlier stages (patients without albuminuria). Therefore, early metabolic control is important, as well as other risk factors that may influence in the development of DN. Large sample size studies are pending to confirm these data.

Background and Aims Hyperkalemia (HK) is a potentially life-threatening condition, in patients with chronic kidney disease (CKD) and congestive heart failure (CHF). The majority of patients affected with CKD or CHF, must be treated with inhibitors of renin angiotensin aldosterone system (RAASi) and mineralocorticoid receptor antagonists (MRAs). However, the treatments previously mentioned, increase the risk of HK episodes, which is the main cause of RAASi and MRAs downtitration or discontinuation, representing an undesirable clinical scenario, given that the patients are at high risk of be deprived of their nephroprotective effect and cardio-renal benefits The aim of the study is: to analyze if, in patients with HK, CKD and CHF treated with RAASi and/or MRA, serum potassium (sK) reduction by Sodium zirconium cyclosilicate (SZC) treatment is non-inferior to RAASi and/or MRAs discontinuation or downtitration. Method Results The study will demonstrate results on serum electrolytes, renal function, albuminuria, KDQoL questionnaire and changes in relative overhydration (multifrequency bioimpedance -BCM Fresenius-) Conclusion The KEEP ON study will define the ability of SZC to facilitate the use of RAAS-I and / or MRA in patients with HK and cardiorenal syndrome allowing the maintenance of the medications recommended by international guidelines for the treatment of CHF at different degrees of CKD while maintaining the potential cardio-renal and nephroprotective benefit.

Background and Aims Abnormalities of bone mineral parameters are associated with increased mortality in patients on dialysis, but their effects and the optimal range of these biomarkers are less well characterized in non-dialysis chronic kidney disease (CKD). Method PECERA (Collaborative Study Project in Patients with Advanced Chronic Kidney Disease) is a 3-year, multicentre, open-cohort, prospective study carried out in 995 adult patients with CKD stages 4-5 not on dialysis enrolled in 2007-09 from 12 centres in Spain. Associations between levels of serum calcium (corrected for serum albumin), phosphate, and intact parathyroid hormone (iPTH) and all-cause mortality were examined using time-dependent Cox proportional hazards models and penalized splines analysis adjusted by demographics and comorbidities, treatments and biochemical collected at baseline and every 6 months for 3 years. Results After a median follow-up of 30 months (IQR:14-37 months) there were 180 deaths (18%). The association of calcium and phosphate with all-cause mortality was U-shaped (Figure). The serum values associated with the minimum risk of mortality were 9.35 mg/dL for calcium and 3.56 mg/dL for phosphate, being the lowest risk ranges between 7.4 to 10.7 mg/dL and between 2.3 to 4.6 mg/dL for calcium and phosphate, respectively. For iPTH levels, the association was J-shaped, with an increased risk for all-cause mortality at levels > 110 pg/mL. Conclusion As previously reported in dialysis patients, PECERA provided evidence on the association of serum calcium, phosphate and iPTH levels with all-cause mortality in stage 4 and 5 CKD patients, suggesting potential survival benefits of controlling bone mineral parameters in this population. Whereas the ranges of calcium and phosphate associated with the lowest mortality in the study were consistent with the current K-DIGO guidelines, our results suggested that the threshold for considering anti-parathyroid treatment might be lower than is currently recommended.