Pieter M. ter Wee

SIMILAR PERITONITIS OUTCOME IN CAPD AND APD PATIENTS WITH DIALYSIS MODALITY CONTINUATION DURING PERITONITIS

♦ Background: As few data exist on treatment of peritonitis in patients on automated peritoneal dialysis (APD), and as pharmacokinetics of several antibiotics are reported to be unfavorable in APD, some favor switching to continuous ambulant PD (CAPD) while treating APD-related peritonitis. We explored whether treating peritonitis with patients continuing their usual PD modality had an effect on outcome. ♦ Methods: We performed a retrospective analysis of the 508 episodes of PD-associated peritonitis seen in 205 patients in our center from January 1993 to January 2007. During this period, the standard initial therapy for PD-related peritonitis was a combination of intraperitoneal gentamicin and rifampicin. ♦ Results: There was no difference in cure rate between CAPD and APD groups. Likewise, initial and maximal leukocyte counts in the PD fluid (PDF), relapse rates, catheter removal rates, and death during treatment of peritonitis were similar in the CAPD and APD groups. Median (interquartile range) duration of elevated leukocyte count in PDF was longer in APD: 5.0 (3.0 – 9.0) days versus 4.0 (2.5 – 7.0) days in CAPD (p <0.001). APD patients were treated with antibiotics longer than CAPD patients: 16.0 (12.5 – 21.0) versus 15.0 (12.0 – 18.0) days (p = 0.036). Also, after correction for possible confounders, odds ratios for death and for the combined end point death or catheter removal showed no difference when patients treated for peritonitis stayed on their own modality. ♦ Conclusion: Regarding rate of relapse, mortality, or the combined end point mortality plus catheter removal, we found no difference between CAPD and APD patients continuing their own PD modality during treatment of PD-related peritonitis. Intermediate end points such as duration of elevated PDF leukocyte count and duration of antibiotic treatment were longer in APD patients.

Fibroblast growth factor 23 and the antiproteinuric response to dietary sodium restriction during renin-angiotensin-aldosterone system blockade.

BACKGROUND Residual proteinuria during renin-angiotensin-aldosterone system (RAAS) blockade is a major renal and cardiovascular risk factor in chronic kidney disease. Dietary sodium restriction potentiates the antiproteinuric effect of RAAS blockade, but residual proteinuria remains in many patients. Previous studies linked high fibroblast growth factor 23 (FGF-23) levels with volume overload; others linked higher serum phosphate levels with impaired RAAS-blockade efficacy. We hypothesized that FGF-23 reduces the capacity of dietary sodium restriction to potentiate RAAS blockade, impairing the antiproteinuric effect. STUDY DESIGN Post hoc analysis of cohort data from a randomized crossover trial with two 6-week study periods comparing proteinuria after a regular-sodium diet with proteinuria after a low-sodium diet, both during background angiotensin-converting enzyme inhibition. SETTING & PARTICIPANTS 47 nondiabetic patients with CKD with residual proteinuria (median protein excretion, 1.9 [IQR, 0.8-3.1] g/d; mean age, 50±13 [SD] years; creatinine clearance, 69 [IQR, 50-110] mL/min). PREDICTOR Plasma carboxy-terminal FGF-23 levels. OUTCOMES Difference in residual proteinuria at the end of the regular-sodium versus low-sodium study period. Residual proteinuria during the low-sodium diet period adjusted for proteinuria during the regular-sodium diet period. RESULTS Higher baseline FGF-23 level was associated with reduced antiproteinuric response to dietary sodium restriction (standardized β=-0.46; P=0.001; model R(2)=0.71). For every 100-RU/mL increase in FGF-23 level, the antiproteinuric response to dietary sodium restriction was reduced by 10.6%. Higher baseline FGF-23 level was a determinant of more residual proteinuria during the low-sodium diet (standardized β=0.27; P=0.003) in linear regression analysis adjusted for baseline proteinuria (model R(2)=0.71). There was no interaction with creatinine clearance (P interaction=0.5). Baseline FGF-23 level did not predict changes in systolic or diastolic blood pressure upon intensified antiproteinuric treatment. LIMITATIONS Observational study, limited sample size. CONCLUSIONS FGF-23 levels are associated independently with impaired antiproteinuric response to sodium restriction in addition to RAAS blockade. Future studies should address whether FGF-23-lowering strategies may further optimize proteinuria reduction by RAAS blockade combined with dietary sodium restriction.

As we grow old: nutritional considerations for older patients on dialysis

The number of older people on dialysis is increasing, along with a need to develop specialized health care to manage their needs. Aging-related changes occur in physiological, psychosocial and medical aspects, all of which present nutritional risk factors ranging from a decline in metabolic rate to assistance with feeding-related activities. In dialysis, these are compounded by the metabolic derangements of chronic kidney disease (CKD) and of dialysis treatment per se, leading to possible aggravation of protein-energy wasting syndrome. This review discusses the nutritional derangements of the older patient on dialysis, debates the need for specific renal nutrition guidelines and summarizes potential interventions to meet their nutritional needs. Interdisciplinary collaborations between renal and geriatric clinicians should be encouraged to ensure better quality of life and outcomes for this growing segment of the dialysis population.

Protective Effects of Paricalcitol on Peritoneal Remodeling during Peritoneal Dialysis

Peritoneal dialysis (PD) is associated with structural and functional alterations of the peritoneal membrane, consisting of fibrosis, angiogenesis, and loss of ultrafiltration capacity. Vitamin D receptor activation (VDRA) plays an important role in mineral metabolism and inflammation, but also antiangiogenic and antifibrotic properties have been reported. Therefore, the effects of active vitamin D treatment on peritoneal function and remodeling were investigated. Rats were either kept naïve to PDF exposure or daily exposed to 10 mL PDF and were treated for five or seven weeks with oral paricalcitol or vehicle control. Non-PDF-exposed rats showed no peritoneal changes upon paricalcitol treatment. Paricalcitol reduced endogenous calcitriol but did not affect mineral homeostasis. However, upon PDF exposure, loss of ultrafiltration capacity ensued which was fully rescued by paricalcitol treatment. Furthermore, PD-induced ECM thickening was significantly reduced and omental PD-induced angiogenesis was less pronounced upon paricalcitol treatment. No effect of paricalcitol treatment on total amount of peritoneal cells, peritoneal leukocyte composition, and epithelial to mesenchymal transition (EMT) was observed. Our data indicates that oral VDRA reduces tissue remodeling during chronic experimental PD and prevents loss of ultrafiltration capacity. Therefore, VDRA is potentially relevant in the prevention of treatment technique failure in PD patients.

Mediterranean diet as the diet of choice for patients with chronic kidney disease.

Traditional dietary management of chronic kidney disease (CKD) focuses on the quantity within the diet of energy and protein, and the restriction of single micronutrients, with little mention of dietary quality. Dietary patterns that are more plant-based, lower in meat (including processed meat), sodium and refined sugar, and have a higher content of grains and fibres are now included in multiple clinical guidelines for chronic disease prevention. The Mediterranean diet (MD) has been associated with reduced cardiovascular disease incidence in both observational and interventional studies. A wealth of evidence links MD with other beneficial effects on chronic diseases such as diabetes, obesity or cognitive health. This review examines each constituent of the classical MD and evaluates their suitability for the management of patients with CKD. We also evaluate the potential hyperkalaemia risk of increasing fruit and vegetable intake. Overall, a decrease in net endogenous acid production and increase in fibre may lead to a better control of metabolic acidosis. This, together with other putative favourable effects of MD on endothelial function, inflammation, lipid profile and blood pressure, provide mechanistic pathways to explain the observed reduced renal function decline and improved survival in CKD patients adhering to an MD.

Can Nutritional Intervention Limit Protein Energy Wasting

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Fluid balance-adjusted creatinine at initiation of continuous venovenous hemofiltration and mortality. A post-hoc analysis of a multicenter randomized controlled trial.

Introduction Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is associated with high mortality. The creatinine-based stage of AKI is considered when deciding to start or delay RRT. However, creatinine is not only determined by renal function (excretion), but also by dilution (fluid balance) and creatinine generation (muscle mass). The aim of this study was to explore whether fluid balance-adjusted creatinine at initiation of RRT is related to 28-day mortality independent of other markers of AKI, surrogates of muscle mass and severity of disease. Methods We performed a post-hoc analysis on data from the multicentre CASH trial comparing citrate to heparin anticoagulation during continuous venovenous hemofiltration (CVVH). To determine whether fluid balance-adjusted creatinine was associated with 28-day mortality, we performed a logistic regression analysis adjusting for confounders of creatinine generation (age, gender, body weight), other markers of AKI (creatinine, urine output) and severity of disease. Results Of the 139 patients, 32 patients were excluded. Of the 107 included patients, 36 died at 28 days (34%). Non-survivors were older, had higher APACHE II and inclusion SOFA scores, lower pH and bicarbonate, lower creatinine and fluid balance-adjusted creatinine at CVVH initiation. In multivariate analysis lower fluid balance-adjusted creatinine (OR 0.996, 95% CI 0.993–0.999, p = 0.019), but not unadjusted creatinine, remained associated with 28-day mortality together with bicarbonate (OR 0.869, 95% CI 0.769–0.982, P = 0.024), while the APACHE II score non-significantly contributed to the model. Conclusion In this post-hoc analysis of a multicentre trial, low fluid balance-adjusted creatinine at CVVH initiation was associated with 28-day mortality, independent of other markers of AKI, organ failure, and surrogates of muscle mass, while unadjusted creatinine was not. More tools are needed for better understanding of the complex determinants of “AKI classification”, “CVVH initiation” and their relation with mortality, fluid balance is only one.