Volume-Independent Sodium Toxicity in Peritoneal Dialysis: New Insights from Bench to Bed

Sodium overload is common in end-stage kidney disease (ESKD) and is associated with increased cardiovascular mortality that is traditionally considered a result of extracellular volume expansion. Recently, sodium storage was detected by Na23 magnetic resonance imaging in the interstitial tissue of the skin and other tissues. This amount of sodium is osmotically active, regulated by immune cells and the lymphatic system, escapes renal control, and, more importantly, is associated with salt-sensitive hypertension. In chronic kidney disease, the interstitial sodium storage increases as the glomerular filtration rate declines and is related to cardiovascular damage, regardless of the fluid overload. This sodium accumulation in the interstitial tissues becomes more significant in ESKD, especially in older and African American patients. The possible negative effects of interstitial sodium are still under study, though a higher sodium intake might induce abnormal structural and functional changes in the peritoneal wall. Interestingly, sodium stored in the interstial tissue is not unmodifiable, since it is removable by dialysis. Nevertheless, the sodium removal by peritoneal dialysis (PD) remains challenging, and new PD solutions are desirable. In this narrative review, we carried out an update on the pathophysiological mechanisms of volume-independent sodium toxicity and possible future strategies to improve sodium removal by PD.

Sex difference in ambulatory blood pressure control associates with risk of ESKD and death in CKD patients receiving stable nephrology care

BACKGROUND

It is unknown whether faster progression of chronic kidney disease (CKD) in men than in women relates to differences in ambulatory blood pressure (ABP) levels.

METHODS

We prospectively evaluated 906 hypertensive CKD patients (553 men) regularly followed in renal clinics to compare men versus women in terms of ABP control [daytime <135/85 and nighttime blood pressure (BP) <120/70 mmHg] and risk of all-cause mortality and end-stage kidney disease (ESKD).

RESULTS

Age, estimated glomerular filtration rate and use of renin-angiotensin system inhibitors were similar in men and women, while proteinuria was lower in women [0.30 g/24 h interquartile range (IQR) 0.10-1.00 versus 0.42 g/24 h, IQR 0.10-1.28, P = 0.025]. No sex-difference was detected in office BP levels; conversely, daytime and nighttime BP were higher in men (134 ± 17/78 ± 11 and 127 ± 19/70 ± 11 mmHg) than in women (131 ± 16/75 ± 11, P = 0.005/P < 0.001 and 123 ± 20/67 ± 12, P = 0.006/P < 0.001), with ABP goal achieved more frequently in women (39.1% versus 25.1%, P < 0.001). During a median follow-up of 10.7 years, 275 patients reached ESKD (60.7% men) and 245 died (62.4% men). Risks of ESKD and mortality (hazard ratio and 95% confidence interval), adjusted for demographic and clinical variables, were higher in men (1.34, 1.02-1.76 and 1.36, 1.02-1.83, respectively). Adjustment for office BP at goal did not modify this association. In contrast, adjustment for ABP at goal attenuated the increased risk in men for ESKD (1.29, 0.98-1.70) and death (1.31, 0.98-1.77). In the fully adjusted model, ABP at goal was associated with reduced risk of ESKD (0.49, 0.34-0.70) and death (0.59, 0.43-0.80). No interaction between sex and ABP at goal on the risk of ESKD and death was found, suggesting that ABP-driven risks are consistent in males and females.

CONCLUSIONS

Our study highlights that higher ABP significantly contributes to higher risks of ESKD and mortality in men.

Anemia: A Connection Between Heart Failure and Kidney Failure

Erythropoiesis-stimulating agents (ESAs) have improved the quality of life and reduced the need for transfusions in patients with chronic kidney disease. However, randomized trials showed no benefit but possible safety issues following high doses of ESAs given to reach normal hemoglobin levels. Iron therapy is used together with ESA; when given proactively, it may reduce the risk of mortality and cardiovascular events in hemodialysis patients. Recent trials also showed benefits of intravenous iron therapy in patients with heart failure. New drugs for correcting anemia may retain the present efficacy of ESAs as antianemic drugs and reduce cardiovascular risks.

Efficacy and durability of multifactorial intervention on mortality and MACEs: a randomized clinical trial in type-2 diabetic kidney disease

BACKGROUND

Multiple modifiable risk factors for late complications in patients with diabetic kidney disease (DKD), including hyperglycemia, hypertension and dyslipidemia, increase the risk of a poor outcome. DKD is associated with a very high cardiovascular risk, which requires simultaneous treatment of these risk factors by implementing an intensified multifactorial treatment approach. However, the efficacy of a multifactorial intervention on major fatal/non-fatal cardiovascular events (MACEs) in DKD patients has been poorly investigated.

METHODS

Nephropathy in Diabetes type 2 (NID-2) study is a multicentre, cluster-randomized, open-label clinical trial enrolling 395 DKD patients with albuminuria, diabetic retinopathy (DR) and negative history of CV events in 14 Italian diabetology clinics. Centres were randomly assigned to either Standard-of-Care (SoC) (n = 188) or multifactorial intensive therapy (MT, n = 207) of main cardiovascular risk factors (blood pressure < 130/80 mmHg, glycated haemoglobin < 7%, LDL, HDL and total cholesterol < 100 mg/dL, > 40/50 mg/dL for men/women and < 175 mg/dL, respectively). Primary endpoint was MACEs occurrence by end of follow-up phase. Secondary endpoints included single components of primary endpoint and all-cause death.

RESULTS

At the end of intervention period (median 3.84 and 3.40 years in MT and SoC group, respectively), targets achievement was significantly higher in MT. During 13.0 years (IQR 12.4-13.3) of follow-up, 262 MACEs were recorded (116 in MT vs. 146 in SoC). The adjusted Cox shared-frailty model demonstrated 53% lower risk of MACEs in MT arm (adjusted HR 0.47, 95%CI 0.30-0.74, P = 0.001). Similarly, all-cause death risk was 47% lower (adjusted HR 0.53, 95%CI 0.29-0.93, P = 0.027).

CONCLUSION

MT induces a remarkable benefit on the risk of MACEs and mortality in high-risk DKD patients. Clinical Trial Registration ClinicalTrials.gov number, NCT00535925. https://clinicaltrials.gov/ct2/show/NCT00535925.

MO464TWO-YEARS CHANGES IN ABPM, CARDIAC AND RENAL PARAMETERS PREDICT CARDIOVASCULAR OUTCOME OF PATIENTS WITH CKD AND HYPERTENSION

Background and Aims

Changes over time in eGFR and albuminuria provide better accuracy than baseline values for end-stage risk prediction in CKD patients, whereas no studies have evaluated the impact of changes in renal, cardiac, and BP parameters on cardiovascular (CV) outcome.

Methods

We prospectively evaluated 249 hypertensive CKD patients with available baseline and 2-year echocardiography and ambulatory blood pressure monitoring (ABPM). Outcome was a composite of death or any non fatal CV event. Predictors of outcome were tested by multivariable regression analysis. The accuracy of prediction models that included baseline and 2-year changes (Δ) in cardiac, renal and BP parameters was assessed by ROC analysis.

Results

During a follow-up period of 71 months, 69 CKD patients (28%) experienced a major CV event or died. By multivariable Cox regression analysis baseline nighttime pulse pressure (PP) (HR 1.01, 95% CI 1.00 to 1.04), left ventricular mass (LVMi) (HR 1.03, 95% CI 1.02 to 1.04), ejection fraction (EF) (HR 0.96, 95% CI 0.90 to 0.97), Δ nighttime PP (HR 1.04, 95% CI 1.01 to 1.07), Δ LVMi (HR 1.02, 95% CI 1.00 to 1.04), and ΔEF (0.93, 95% CI 0.89-0.97) were associated with outcome. A model that includes 2-year changes in LVMi, EF, proteinuria, and nighttime PP was more accurate than a model that only evaluated baseline values (Δc-statistic 0.08, 95% CI 0.02 to 0.13, P=0.006; net reclassification improvement -NRI- 0.24, P= &lt; 0.0001).

Conclusion

Estimation of 2-year changes in renal, cardiac, and BP parameters improve the predictive accuracy of adverse CV outcome in CKD patients followed in tertiary care.

Types of erythropoiesis-stimulating agents and risk of end-stage kidney disease and death in patients with non-dialysis chronic kidney disease

BACKGROUND

Despite the widespread use of erythropoiesis-stimulating agents (ESAs) to treat anaemia, the risk of adverse outcomes associated with the use of different types of ESAs in non-dialysis chronic kidney disease (CKD) is poorly investigated.

METHODS

From a pooled cohort of four observational studies, we selected CKD patients receiving short-acting (epoetin α/β; n = 299) or long-acting ESAs (darbepoetin and methoxy polyethylene glycol-epoetin β; n = 403). The primary composite endpoint was end-stage kidney disease (ESKD; dialysis or transplantation) or all-cause death. Multivariable Cox models were used to estimate the relative risk of the primary endpoint between short- and long-acting ESA users.

RESULTS

During follow-up [median 3.6 years (interquartile range 2.1-6.3)], the primary endpoint was registered in 401 patients [166 (72%) in the short-acting ESA group and 235 (58%) in the long-acting ESA group]. In the highest tertile of short-acting ESA dose, the adjusted risk of primary endpoint was 2-fold higher {hazard ratio [HR] 2.07 [95% confidence interval (CI) 1.37-3.12]} than in the lowest tertile, whereas it did not change across tertiles of dose for long-acting ESA patients. Furthermore, the comparison of ESA type in each tertile of ESA dose disclosed a significant difference only in the highest tertile, where the risk of the primary endpoint was significantly higher in patients receiving short-acting ESAs [HR 1.56 (95% CI 1.09-2.24); P = 0.016]. Results were confirmed when ESA dose was analysed as continuous variable with a significant difference in the primary endpoint between short- and long-acting ESAs for doses >105 IU/kg/week.

CONCLUSIONS

Among non-dialysis CKD patients, the use of a short-acting ESA may be associated with an increased risk of ESKD or death versus long-acting ESAs when higher ESA doses are prescribed.

Ferric Carboxymatose in Non-Hemodialysis CKD Patients: A Longitudinal Cohort Study

No information is available on the efficacy of ferric carboxymaltose (FCM) in real-world CKD patients outside the hemodialysis setting. We prospectively followed 59 non-hemodialysis CKD patients with iron deficient anemia (IDA: hemoglobin <12.0/<13.5 g/dL in women/men and TSAT < 20% and/or ferritin < 100 ng/mL) who were intolerant or non-responders to oral iron. Patients received ferric carboxymaltose (FCM) (single dose of 500 mg) followed by additional doses if iron deficiency persisted. We evaluated efficacy of FCM in terms of increase of hemoglobin, ferritin, and TSAT levels. Direct and indirect costs of FCM were also analyzed in comparison with a hypothetical scenario where same amount of iron as ferric gluconate (FG) was administered intravenously. During the 24 weeks of study, 847 ± 428 mg of FCM per patient were administered. IDA improved after four weeks of FCM and remained stable thereafter. At week-24, mean change (95%CI) from baseline of hemoglobin, ferritin and TSAT were +1.16 g/dL (0.55–1.77), +104 ng/mL (40–168) and +9.5% (5.8–13.2), respectively. These changes were independent from ESA use and clinical setting (non-dialysis CKD, peritoneal dialysis and kidney transplant). Among ESA-treated patients (n = 24), ESA doses significantly decreased by 26% with treatment and stopped either temporarily or persistently in nine patients. FCM, compared to a FG-based scenario, was associated with a cost saving of 288 euros/patient/24 weeks. Saving was the same in ESA users/non-users. Therefore, in non-hemodialysis CKD patients, FCM effectively corrects IDA and allows remarkable cost savings in terms of societal, healthcare and patient perspective.

Role of Albuminuria in Detecting Cardio-Renal Risk and Outcome in Diabetic Subjects

The clinical significance of albuminuria in diabetic subjects and the impact of its reduction on the main cardiorenal outcomes by different drug classes are among the most interesting research focuses of recent years. Although nephrologists and cardiologists have been paying attention to the study of proteinuria for years, currently among diabetics, increased urine albumin excretion ascertains the highest cardio-renal risk. In fact, diabetes is a condition by itself associated with a high-risk of both micro/macrovascular complications. Moreover, proteinuria reduction in diabetic subjects by several treatments lowers both renal and cardiovascular disease progression. The 2019 joint ESC-EASD guidelines on diabetes, prediabetes and cardiovascular (CV) disease assign to proteinuria a crucial role in defining CV risk level in the diabetic patient. In fact, proteinuria by itself allows the diabetic patient to be staged at very high CV risk, thus affecting the choice of anti-hyperglycemic drug class. The purpose of this review is to present a clear update on the role of albuminuria as a cardio-renal risk marker, starting from pathophysiological mechanisms in support of this role. Besides this, we will show the prognostic value in observational studies, as well as randomized clinical trials (RCTs) demonstrating the potential improvement of cardio-renal outcomes in diabetic patients by reducing proteinuria.

Selective endothelin A receptor antagonism in patients with proteinuric chronic kidney disease

Introduction: Selective antagonists of Endothelin-1 receptors (ERA) have been tested in diabetic and nondiabetic chronic kidney disease (CKD). The SONAR trial (Study Of diabetic Nephropathy with AtRasentan) was the first randomized, phase 3, study assessing the long-term effect of ERA on CKD progression.Areas covered: We examine the ERA effects in proteinuric CKD. We discuss the results of the main clinical studies on ERA in CKD and offer an opinion on the findings of SONAR study and future perspectives in this field. We searched in PubMed and ISI Web of Science databases for including experimental and clinical studies that evaluated ERA in proteinuric CKD.Expert opinion: The SONAR study demonstrated that ERA confers protection against risk for CKD progression. This trial stimulated clinical research on ERA, to expand the therapeutic opportunities in CKD patients. Two novel phase 3 studies testing ERA in patients with glomerular disease are ongoing. Within the context of personalized medicine, we think it would be relevant to evaluate the effect of multiple treatments, including ERA, in proteinuric CKD patients. Testing ERA in clinical trials of novel design will also help at identifying the patients who would more benefit from these drugs.

Area Deprivation and Risk of Death and CKD Progression: Long-Term Cohort Study in Patients under Unrestricted Nephrology Care

BACKGROUND

Area deprivation index (ADI) associates with prognosis in non-dialysis CKD. However, no study has evaluated this association in CKD patients under unrestricted nephrology care.

METHODS

We performed a long-term prospective study to assess the role of deprivation in CKD progression and mortality in stage 1-4 CKD patients under regular nephrology care, living in Naples (Italy). We used ADI calculated at census block levels, standardized to mean values of whole population in Naples, and linked to patients by georeference method. After 12 months of "goal-oriented" nephrology treatment, we compared the risk of death or composite renal outcomes (end-stage kidney disease or doubling of serum creatinine) in the tertiles of standardized ADI. Estimated glomerular filtration rate (eGFR) decline was evaluated by mixed effects model for repeated eGFR measurements.

RESULTS

We enrolled 715 consecutive patients (age: 64 ± 15 years; 59.1% males; eGFR: 49 ± 22 mL/min/1.73 m2). Most (75.2%) were at the lowest national ADI quintile. At referral, demographic, clinical, and therapeutic features were similar across ADI tertiles; after 12 months, treatment intensification allowed better control of hypertension, proteinuria, hypercholesterolaemia, and anaemia with no difference across ADI tertiles. During the subsequent long-term follow-up (10.5 years [interquartile range 8.2-12.6]), 166 renal events and 249 deaths were registered. ADI independently associated with all-cause death (p for trend = 0.020) and non-cardiovascular (CV) mortality (p for trend = 0.045), while CV mortality did not differ (p for trend = 0.252). Risk of composite renal outcomes was similar across ADI tertiles (p for trend = 0.467). The same held true for eGFR decline (p for trend = 0.675).

CONCLUSIONS

In CKD patients under regular nephrology care, ADI is not associated with CKD progression, while it is associated with all-cause death due to an excess of non-CV mortality.

Reclassification of chronic kidney disease patients for end-stage renal disease risk by proteinuria indexed to estimated glomerular filtration rate: multicentre prospective study in nephrology clinics

BACKGROUND

In non-dialysis chronic kidney disease (CKD), absolute proteinuria (Uprot) depends on the extent of kidney damage and residual glomerular filtration rate (GFR). We therefore evaluated, as compared with Uprot, the strength of association of proteinuria indexed to estimated GFR (eGFR) with end-stage renal disease (ESRD) risk.

METHODS

In a multi-cohort prospective study in 3957 CKD patients of Stages G3-G5 referred to nephrology clinics, we tested two multivariable Cox models for ESRD risk, with either Uprot (g/24 h) or filtration-adjusted proteinuria (F-Uprot) calculated as Uprot/eGFR ×100.

RESULTS

Mean ± SD age was 67 ± 14 years, males 60%, diabetics 29%, cardiovascular disease (CVD) 34%, eGFR 32 ± 13 mL/min/1.73 m2, median (interquartile range) Uprot 0.41 (0.12-1.29) g/24 h and F-Uprot 1.41 (0.36-4.93) g/24 h per 100 mL/min/1.73 m2 eGFR. Over a median follow-up of 44 months, 862 patients reached ESRD. At competing risk analysis, ESRD risk progressively increased when F-Uprot was 1.0-4.9 and ≥5.0 versus <1.0 g/24 h per 100 mL/min/1.73 m2 eGFR in Stages G3a-G4 (P < 0.001) and Stage G5 (P = 0.002). Multivariable Cox analysis showed that Uprot predicts ESRD in Stages G3a-G4 while in G5 the effect was not significant; conversely, F-Uprot significantly predicted ESRD at all stages. The F-Uprot model allowed a significantly better prediction versus the Uprot model according to Akaike information criterion. Net reclassification improvement was 12.2% (95% confidence interval 4.2-21.1), with higher reclassification in elderly, diabetes and CVD, as well as in diabetic nephropathy and glomerulonephritis, and in CKD Stages G4 and G5.

CONCLUSIONS

In patients referred to nephrology clinics, F-Uprot predicts ESRD at all stages of overt CKD and improves, as compared with Uprot, reclassification of patients for renal risk, especially in more advanced and complicated disease.

[Treating anaemia in patients with chronic kidney disease: what evidence for using ESAs, after a 30-year journey?]

Erythropoiesis Stimulating Agents (ESAs) are well-tolerated and effective drugs for the treatment of anaemia in patients with chronic kidney disease. In the past, scientific research and clinical practice around ESAs have mainly focused on the haemoglobin target to reach, and to moving towards the normality range; more cautious approach has been taken more recently. However, little attention has been paid to possible differences among ESA molecules. Although they present a common mechanism of action on the erythropoietin receptor, their peculiar pharmacodynamic characteristics could give different signals of activation of the receptor, with possible clinical differences. Some studies and metanalyses did not show significant differences among ESAs. More recently, an observational study of the Japanese Registry of dialysis showed a 20% higher risk of mortality from any cause in the patients treated with long-acting ESAs in comparison to those treated with short-acting ESAs; the difference increased in those treated with higher doses. These results were not confirmed by a recent, post-registration, randomised, clinical trial, which did not show any significant difference in the risk of death from any cause or cardiovascular events between short-acting ESAs and darbepoetin alfa or methoxy polyethylene glycol-epoetin beta. Finally, data from an Italian observational study, which was carried out in non-dialysis CKD patients, showed an association between the use of high doses of ESA and an increased risk of terminal CKD, limited only to the use of short-acting ESAs. In conclusion, one randomised clinical trial supports a similar safety profile for long- versus short-acting ESAs. Observational studies should always be considered with some caution: they are hypothesis generating, but they may suffer from bias by indication.

[Remote patient monitoring in dialysis patients: the "change of pace" for home dialysis.]

Lockdown and self-isolation are to date the only solution to limit the spread of recent outbreak of coronavirus disease (CoViD-19), highlighting the great advantage of home dialysis in a patient otherwise forced to travel from / to the dialysis center to receive this "life-saving" treatment. Indeed, to prevent spreading of CoViD-19 infection among extremely fragile dialysis patients, as well as among dialysis workers, hemodialysis (HD) centers are adopting specific procedures ("dedicated" dialysis facilities, portable osmosis, etc.) with a great economic and organizational commitment. Peritoneal dialysis (PD) represents a type of home dialysis therapy not yet adequately implemented to date, in spite of safe and simple practice, as well as similar dialytic efficiency vs in-center hemodialysis. Remote patient monitoring (RPM) systems have been developed in automated PD (APD) cyclers in order to improve the acceptance of this dialysis method, to increase the compliance to the prescribed therapy and to control treatment adequacy. In this review we assess the potential advantages of RPM in APD, that are the chance for patients to acquire greater independence and safety in the home treatment, to allow better access to care for residents in remote areas, faster resolution of problems, reduction in hospitalizations and mortality rates, as well as time and cost saving for both the patient and the staff. The use of medical devices (sphygmomanometer, glucometer, balance, etc.), connected by wireless to the clinician's portal, might also allow a wider diffusion of incremental dialysis, an integrated therapy that combines conservative management of ESKD patients with a soft dialysis based on the residual kidney function and symptomatology, with potential prognosis and economic benefits. Although the majority of the studies are small and observational, a wider use of RPM systems is desirable to broaden the spread of home dialysis, as we learnt from Coronavirus pandemic.

Cost-analysis of persistent hyperkalaemia in non-dialysis chronic kidney disease patients under nephrology care in Italy

AIM

In patients with chronic kidney disease (CKD), hyperkalaemia (HK) (potassium level ≥ 5.0 mEq/L) is associated with poor clinical outcomes. This study provides novel insights by comparing management costs of CKD patients with normokalaemia vs those with persistent HK regularly followed in renal clinics in Italy.

METHODS

To this aim, a Markov model over life-time horizon was developed. Time to end-stage renal disease (ESRD) and time to death in CKD patients were derived from an observational multi-centre database including 1665 patients with non-dialysis CKD stage 1-5 under nephrology care in Italy (15 years follow-up). Resource use for CKD and HK management was obtained from the observational database, KDIGO international guidelines, and clinical expert opinion.

RESULTS

Results showed that patients with normokalaemia vs persistent HK brought an average per patient lifetime cost-saving of €16 059 besides delayed onset of ESRD by 2.29 years and increased survival by 1.79 years with increment in total survival and dialysis-free survival in normokalaemia that decreased from early to advanced disease. Cost-saving related to normokalaemia increased at more advanced CKD; however, it was already evident at early stage (3388.97€ at stage 1-3a). OWSA confirmed cost-saving associated with normokalaemia across all parameter variations.

DISCUSSION AND CONCLUSION

This model is the first to simulate the impact of HK in non-dialysis CKD patients on economic and clinical outcomes using real-world data from nephrology clinics. In these patients, persistent HK results into higher lifetime costs, besides poorer clinical outcomes, that are evident since the early stages of CKD. Maintaining normokalaemia should therefore be of main concern in CKD treatment planning to improve long-term economic and clinical outcomes.

Are all erythropoiesis-stimulating agents created equal?

Erythropoiesis-stimulating agents (ESAs) are effective drugs to correct and maintain haemoglobin (Hb) levels, however, their use at doses to reach high Hb targets has been associated with an increased risk of cardiovascular adverse events, mortality and cancer. Presently used ESAs have a common mechanism of action but different pharmacokinetic and pharmacodynamic characteristics. Accordingly, the mode of activation of the erythropoietin (EPO) receptor can exert marked differences in downstream events. It is unknown whether the various ESA molecules have different efficacy/safety profiles. The relative mortality and morbidity risks associated with the use of different types of ESAs remains poorly evaluated. Recently an observational study and a randomized clinical trial provided conflicting results regarding this matter. However, these two studies displayed several differences in patient characteristics and ESA molecules used. More importantly, by definition, randomized clinical trials avoid bias by indication and suffer less from confounding factors. Therefore they bring a higher degree of evidence. The scenario becomes even more complex when considering the new class of ESAs, called prolyl-hydroxylase domain (PHD) inhibitors. They are oral drugs that mimic exposure to hypoxia and stabilize hypoxia-inducible factor α. They profoundly differ from presently used ESAs, as they have multiple targets of action, including the stimulation of endogenous EPO synthesis, direct mobilization/absorption of iron and a higher reduction of hepcidin. Accordingly, they have the potential to be more effective in inflamed patients with functional iron deficiency, i.e. the setting of patients who are at higher risk of cardiovascular events and mortality in response to present ESA use. As for ESAs, individual PHD inhibitors differ in molecular structure and degree of selectivity for the three main PHD isoforms; their efficacy and safety profiles may therefore be different from that of presently available ESAs.

Sodium toxicity in peritoneal dialysis: mechanisms and "solutions"

The major trials in peritoneal dialysis (PD) have demonstrated that increasing peritoneal clearance of small solutes is not associated with any advantage on survival, whereas sodium and fluid overload heralds higher risk of death and technique failure. On the other hand, higher sodium and fluid overload due to loss of residual kidney function (RKF) and higher transport membrane is associated with poor patient and technique survival. Recent experimental studies also show that, independently from fluid overload, sodium accumulation in the peritoneal interstitium exerts direct inflammatory and angiogenetic stimuli, with consequent structural and functional changes of peritoneum, while in patients with Chronic Kidney Disease sodium stored in interstitial skin acts as independent determinant of left ventricular hypertrophy. Noteworthy, this tissue pool of sodium is modifiable being removed by dialysis. Therefore, novel PD strategies to optimize sodium removal, including the use of bimodal and/or low-sodium solutions, are actively tested. Nonetheless, a holistic approach aimed at preserving peritoneal function and the kidney may represent the key of therapy success in the hard task of preserving adequate sodium balance in PD patients. In this review, we describe the available evidence on sodium toxicity in PD, either related or unrelated to fluid overload, and we also discuss about possible "solutions" to preserve or restore sodium balance in PD patients.

Cardiorenal prognosis by residual proteinuria level in diabetic chronic kidney disease: pooled analysis of four cohort studies

Background

No study has assessed whether the prognosis of coexisting diabetes mellitus and chronic kidney disease (DM-CKD) is dictated by DM per se or by the extent of proteinuria.

Methods

In this pooled analysis of four prospective studies in CKD patients treated with drugs inhibiting the renin-angiotensin system, we compared the risk of all-cause mortality, fatal and non-fatal cardiovascular (CV) events and end-stage renal disease (ESRD) between patients with (n = 693) and without diabetes (n = 1481) stratified by proteinuria level (<0.15, 0.15-0.49, 0.5-1 and  >1 g/day).

Results

The group with DM-CKD was older (69 ± 11 versus 65 ± 15 years), had a higher body mass index (29.6 ± 5.4 versus 27.5 ± 4.8 kg/m2) and systolic blood pressure (143 ± 19 versus 136 ± 18 mmHg), prevalent CV disease (48% versus 29%) and lower estimated glomerular filtration rate (34.5 ± 17.9 versus 36.6 ± 19.0 mL/min/1.73 m2). During 4.07 years of follow-up, there were 466 patients with ESRD, 334 deaths and 401 CV events occurred. In the subgroup with urine protein <0.15 g/day (N = 662), the risks of ESRD, CV events and mortality were similar in diabetic and non-diabetic patients. Conversely, in DM-CKD patients, the mortality risk was higher in proteinuric patients {hazard ratio 1.92 [95% confidence interval (CI) 1.25-2.95); 1.99 (1.26-3.15) and 1.98 (1.28-3.06) for proteinuria 0.15-0.49, 0.5-1 and >1 g/day, respectively}, whereas in non-diabetics the mortality risk increased only for proteinuria 0.5-1 g/day [HR 1.60 (95% CI 1.07-2.40)] and >1 g/day [HR 1.69 (95% CI1.20-2.55)]. In both groups, CV risk had a trend similar to that of mortality. ESRD risk increased progressively across strata >0.5 g/day independent of diabetic status.

Conclusions

We provide evidence that patients with non-proteinuric DM-CKD are not exposed to higher cardiorenal risk. In contrast, in the presence of moderate proteinuria and diabetes per se is associated with a higher risk of mortality and CV events, whereas the entity of abnormal proteinuria modulates ESRD risk independent of diabetes.

Relationship between albuminuric CKD and diabetic retinopathy in a real-world setting of type 2 diabetes: Findings from No blind study

BACKGROUND AND AIMS

Recently, the albuminocentric view of diabetic kidney disease (DKD) in type 2 diabetes (T2DM) has been changing. Therefore, the relationship between diabetic retinopathy (DR) and chronic kidney disease (CKD) has to be addressed according to this new clinical presentation of DKD. The aim of this study was to evaluate, in a real-world setting, the correlation DR-DKD in T2DM.

METHODS AND RESULTS

A total of 2068 type 2 diabetic patients enrolled in a multicenter cross-sectional study were investigated. Albuminuric subjects were largely prevalent among subjects with DR (p = 0.019). In the whole study population, no difference in albumin excretion rate (AER) was observed between presence/absence of DR; instead, AER was significantly higher among patients with glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² (CKD) (p = 0.009), above all in those with CKD and AER ≥0.03 g/24 h (p = 0.005). Multivariate analysis confirmed that eGFR (O.R. 0.976; 95% C.I.: 0.960-1.028; p < 0.001) and AER (O.R. 1.249; 95% C.I. 1.001-1.619; p = 0.004) were independently associated with DR and HDL-cholesterol (O.R.: 1.042; 95% C.I.: 1.011-1.120; p = 0.014). Additionally, among patients with eGFR <60 mL/min/1.73 m² and albuminuria, both eGFR and AER significantly varied between those with/without DR (p = 0.012 and p = 0.005, respectively), and this finding was observed among only albuminuric patients. Analogous results were obtained considering DR classification. AER was significantly higher among subjects with either proliferative DR (PDR) or severe nonproliferative DR (NPDR), with regard to mild NPDR (0.498 and 0.938 g/die vs. 0.101 g/die; p < 0.001, respectively). Similar results were obtained in the specular subgroups.

CONCLUSION

In T2DM with DKD, the AER seems to be related to the presence of DR. This association is confirmed above all in those with more severe DR.

Sex Differences in the Progression of CKD Among Older Patients: Pooled Analysis of 4 Cohort Studies

RATIONALE & OBJECTIVE

Data for the association of sex with chronic kidney disease (CKD) progression are conflicting, a relationship this study sought to examine.

STUDY DESIGN

Pooled analysis of 4 Italian observational cohort studies.

SETTING & PARTICIPANTS

1,311 older men and 1,024 older women with estimated glomerular filtration rate (eGFR)<45mL/min/1.73m² followed up in renal clinics.

PREDICTOR

Sex.

OUTCOMES

End-stage kidney disease (ESKD), defined as maintenance dialysis or kidney transplantation, as the primary outcome; all-cause mortality and eGFR decline as secondary outcomes.

ANALYTICAL APPROACH

Cox proportional hazard analysis to estimate the relative risk for ESKD and mortality and linear mixed models to estimate the rate of eGFR decline.

RESULTS

Age, systolic blood pressure, and use of renin-angiotensin system inhibitors were similar in men and women. Baseline eGFRs were 27.6±10.2 in men and 26.0±10.6mL/min/1.73m² in women (P<0.001), while median proteinuria was lower in women (protein excretion, 0.45 [IQR, 0.14-1.10] g/d) compared with men (0.69 [IQR 0.19-1.60] g/d; P<0.001). During a median follow-up of 4.2 years, 757 developed ESKD (59.4% men) and 471 died (58.4% men). The adjusted risks for ESKD and mortality were higher in men (HRs of 1.50 [95% CI, 1.28-1.77] and 1.30 [95% CI, 1.06-1.60], respectively). This finding was consistent across CKD stages. We observed a significant interaction between sex and proteinuria, with the risk for ESKD in men being significantly greater than for women at a level of proteinuria of ∼0.5g/d or greater. The slope of decline in eGFR was steeper in men (-2.09; 95% CI, -2.21 to-1.97mL/min/1.73m² per year) than in women (-1.79; 95% CI, -1.92 to-1.66mL/min/1.73m² per year; P<0.001). Although sex differences in eGFR decline were not different across CKD stages (P=0.3), the difference in slopes between men and women was progressively larger with proteinuria >0.5g/d (P = 0.04).

LIMITATIONS

Residual confounding; only whites were included.

CONCLUSIONS

Excess renal risk in men may, at least in part, be related to higher levels of proteinuria in men compared with women.

[Peritoneal dialysis catheter infection with abscess of the abdominal wall in a ADPKD patient]

Infections to the peritoneal catheter are common in Peritoneal Dialysis (PD). We report the clinical case of a 49-year-old male patient in PD, who showed an atypical manifestation of tunnel infection caused by Staphylococcus aureus. The infection was characterized by a little abscess, on the left pararectal abdominal line, 6 cm far from exit-site of the peritoneal catheter. The diagnosis was made using ultrasonography (US), which showed a fistulous communication from subcutaneous cuff to the skin. We treated the infection conservatively by performing cuff-shaving and drainage of the abscess, associated to antibiotic therapy (teicoplanin). Due to the persistence of the infection, we added oral and topical rifampicin, and advanced medication with freez-dried collagen plant impregnated with extended-release gentamicin. The complete resolution of the infection allowed us to avoid removing the catheter.

[Role of Ambulatory Blood Pressure Monitoring (ABPM) in chronic kidney patients: a review]

About 90%of patients with chronic kidney disease (CKD) have arterial hypertension; the main international guidelines recommend maintaining blood pressure (BP) values below 130/80 mmHg to reduce the cardio-renal risk in this population. Twenty-four-hour Ambulatory Blood Pressure Monitoring (ABPM) is the golden standard for the identification of the BP profiles and patterns, as well as for the assessment of the circadian rhythm and BP variability. The correct interpretation of ABPM allows to optimize anti-hypertensive treatment and to reduce cardio-renal risk in CKD patient. In fact, in patients with CKD, the ABPM has a greater role in terms of renal and cardio-vascular prognosis when compared to clinical BP measurements. Patients with ABPM in target present a low cardio-renal risk, regardless of clinical BP values; on the contrary, if the clinical PA is normal and the ABPM not in target, this risk increases significantly. Moreover, in the CKD population, non-dipping is associated with a higher risk of cardiovascular events and end stage renal disease (ESRD), making identifying nocturnal hypertension greatly important. Therefore, ABPM is an instrument of primary importance in the diagnostic and therapeutic work-out of renal patients.

[Ultrasonography in chronic lithium nephropathy: a case report]

Lithium has always been used as a first-choice therapy in bipolar disorders. However, its therapeutic index is restricted by placing patients at risk of potential nephrotoxic effects ranging from polyuria, to Insipid Nephrogenic Diabetes, to chronic kidney disease with a slow reduction of renal function over time. The Nephrologist has the role to diagnose chronic lithium nephropathy, monitoring its evolution and optimizing the management of risks associated with the treatment. In fact, the main objective, to be shared with the psychiatrist, is to encourage the maintenance of therapy even in the presence of nephropathy. Renal ultrasound, a safe, repeatable and low-cost technique, is essential to pursue this goal as it not only confirms the diagnosis of chronic lithium nephropathy hypothesized on the basis of the history and clinical picture, but is also helpful in monitoring its evolution. In this paper, we report a case of chronic lithium nephropathy in order to analyze the etiopathogenesis of renal damage, the clinical-laboratory and histological picture and, in particular, the fundamental role of ultrasound imaging.

[Infected hepatic cyst in ADPKD patient in peritoneal dialysis]

Renal and hepatic cysts infections are among the most important infectious complications of ADPKD and often require hospitalization. Liver cysts are even more complex than renal cysts and their diagnosis and treatment are quite controversial. We report the case of a 58-year-old patient with ADPKD undergoing peritoneal dialysis treatment. He presented fever and severe asthenia and was diagnosed with a hepatic cyst infection. Given the presence of the peritoneal catheter, and in order to facilitate the targeted treatment of the infection, we administered antibiotics (ceftazidime and teicoplanin) in the bags used for peritoneal dialysis exchanges for 4 weeks, obtaining the complete disappearance of symptoms and laboratory and ultrasound alterations. Intraperitoneal antibiotics administration in the treatment of infected hepatic cysts represents an effective and safe therapeutic alternative, never described in literature so far.