Anabela Rodrigues

Introduction: Peritoneal dialysis is a kidney replacement therapy with outcomes comparable to hemodialysis, although kidney transplantation remains the optimal treatment. The appropriate timing for removing the peritoneal dialysis catheter after transplantation is uncertain, as it may affect patient recovery and graft performance. This study aimed to evaluate infectious complications associated with retained peritoneal dialysis catheters after transplantation and to identify a suitable moment for their removal. Methods: A retrospective review of all patients who underwent kidney transplantation between January 2013 and June 2023 was performed. Descriptive and inferential analyses were used to assess the timing of catheter removal, catheter-related infections, and post-transplant dialysis needs. Continuous variables were analyzed with the Mann-Whitney U test, while nominal variables were evaluated using Chi-square or Fisher’s exact tests. Results: The median time to catheter removal was 4.5 months. Infectious complications occurred in 21 patients, representing 17.2% of the cohort, with exit-site infections being the most frequent event. Donor type and prior infections did not significantly influence infection rates. In living-donor transplantations, only 4.5% of catheters were removed during the transplant surgery. Discussion: These findings support individualized decisions regarding peritoneal dialysis catheter removal, particularly for patients with a low risk of delayed graft function. A risk-based decision algorithm is proposed to assist clinicians. Although current practice aligns with existing guidance, the infectious risks linked to maintaining the catheter suggest that earlier removal should be considered. A tailored approach may improve clinical outcomes and facilitate a safer transition from peritoneal dialysis to kidney transplantation.

Background: Obesity has a negative impact in kidney health. However, the hallmarks of kidney dysfunction in bariatric surgery candidates are poorly characterized. To address this knowledge gap, we used a propensity score-matched analysis to compare kidney lesion biomarkers in bariatric surgery candidates and living kidney donors. Methods: Bariatric surgery candidates attending a single center for obesity treatment were pair-matched for sex and age to potential living kidney transplant donors (PLKD) using a 1:1 nearest-neighbor approach (N = 400, n = 200/group). A 24-h urine collection was used to analyze proteinuria and creatinine clearance. Results: Patients with obesity (PWO) had higher creatinine clearance when compared to PLKD (143.35 ± 45.50 mL/min vs 133.99 ± 39.06 mL/min, p = 0.03), which was underestimated when correction for body surface area (BSA) was used (creatinine clearance corrected for BSA of 115.25 ± 33.63 mL/min/1.73 m² in PWO vs 135.47 ± 35.56 mL/min/1.73 m² in PLKD). Proteinuria was also higher in PWO compared to PLKD (139.82 ± 353.258 mg/day vs 136.35 ± 62.24 mg/day, p < 0.0001). Regression analysis showed that creatinine clearance was strongly correlated with proteinuria in PWO (HR 1.522, p = 0.005), but it was less evident in PLKD (HR 0.376, p = 0.001). Conclusion: Hyperfiltration and disproportionate proteinuria are frequent in patients with obesity. Since hyperfiltration can be underestimated by adjusting creatinine clearance for BSA, this should not be used when evaluating kidney function in bariatric surgery candidates.

Frailty is a clinical syndrome characterized by a state of increased vulnerability and risk of adverse outcomes following a stress, which exerts a heavy economic and social burden. The identification of this syndrome is done throught validated tools. Although frailty is associated with advanced age, certain conditions that produce age-like changes can lead to a state of frailty at younger ages. The presence of multiple comorbidities increases frailty risk. Also, low levels of albumin, even in the normal range, have been related to greater frailty and its levels have been used to assess frailty. Chronic kidney disease is associated with higher prevalence of frailty. However, little has been reported about frailty prevalence in peritoneal dialysis population. Our aim was to access the prevalence of frail and vulnerable PD patients using the Edmonton Frailty Scale (EFS) and to identify prediction factors. In a retrospective cohort study, we assessed frailty in PD patients from 2 center in Portugal by a validated frailty score (Edmonton Frailty Scale-EFS). We also collected information that could contribute to frailty in these patients. Linear and logistic regressions were used to access frailty predictors. Receiver operating characteristics (ROC) curve was used to access accuracy of those predictors. We included 74 PD patients, 51,5% male, mean age 53,9 ± 15,1 years, median body max index 25,2 ± 4,3 Kg/m². Median CCI was 4 [interquartile range (IQR) of 3]. Fifty-three patients (71,6%) were classified as robust (non-frail), 11 as vulnerable, and 10 as frail (8 mildly and 2 moderate). Patients were divided into two groups: A group included robust (non-frail) patients; B group included vulnerable and frail ones. Age, sex distribution, IMC, diabetes mellitus prevalence, variables related to PD (efficacy, vintage, modality and complications), and levels of hemoglobin, phosphorus, potassium and C-reactive protein were similar between the groups. Non frail patients presented significantly higher albumin levels and lower CCI (p-value < 0,05). A linear regression was performed to ascertain the effects of CCI and albumin: CCI was an independent predictor for frailty/vulnerability, accessed by EFS (for each point in CCI, there was an increase of 0,5 points in EFS). Albumin did not show a significant effect defining frailty in our sample. ROC curve showed a high accuracy for CCI to identify frail/ vulnerable patients (AUC 0,817). In our sample, CCI was an independent factor for frailty/vulnerability classified through EFS. In fact, it had a high accuracy to identify those patients, with a high sensibility. This means that CCI could be used as an acceptable screening test. However, the prevalence of frail/vulnerable patients was low in our sample. A larger one will allow to determine confirm if certain comorbidities, such as diabetes mellitus, or variables related to dialysis technique, are correlated with frailty. Furthermore, a larger sample would be essential to confirm whether albumin is, after all, a good predictor of frailty in the PD population, which was not confirmed in this work.

Obesity surgery candidates are at an increased risk of kidney injury, but pre-operative evaluation usually neglects kidney function assessment. This study aimed to identify renal dysfunction in candidates for bariatric surgery. To reduce the sources of bias, subjects with diabetes, prediabetes under metformin treatment, neoplastic or inflammatory diseases were excluded. Patients’ (n = 192) average body mass index was 41.7 ± 5.4 kg/m². Among these, 51% (n = 94) had creatinine clearance over 140 mL/min, 22.4% (n = 43) had proteinuria over 150 mg/day and 14.6% (n = 28) albuminuria over 30 mg/day. A creatinine clearance higher than 140 mL/min was associated with higher levels of proteinuria and albuminuria. Univariate analysis identified sex, glycated hemoglobin, uric acid, HDL and VLDL cholesterol as being associated with albuminuria, but not with proteinuria. On multivariate analysis, glycated hemoglobin and creatinine clearance as continuous variables were significantly associated with albuminuria. In summary, in our patient population prediabetes, lipid abnormalities and hyperuricemia were associated with albuminuria, but not with proteinuria, suggesting different disease mechanisms might be implicated. Data suggest that in obesity-associated kidney disease, tubulointerstitial injury precedes glomerulopathy. A significant proportion of obesity surgery candidates present clinically relevant albuminuria and proteinuria along with renal hyperfiltration, suggesting that routine pre-operative assessment of these parameters should be considered.

Recent awareness of the viability and benefits of incremental hemodialysis is an opportunity to review clinical practices and improve the process of dialysis induction. Incremental dialysis is a standard approach in peritoneal dialysis prescription, with a focus on the quality parameter of nephroprotection. The same should apply in hemodialysis, with individualization of the prescribed extracorporeal technique: frequency, duration and intensity, in either home or center hemodialysis, are prescription variables to adjust according to the patient’s residual renal function, medical condition and psycho-social priorities. Considering that fluid balance and smooth ultrafiltration critically impact patient survival, incremental dialysis schedules need to be carefully tailored and grounded in routine residual kidney function measurement. This paper raises concerns about both the benefits of incremental dialysis and its putative detrimental effects, these being mainly dependent on the quality of the hemodialysis prescription and external economic constraints. As a comparator, incremental peritoneal dialysis is a scientifically based model to pursue, whichever the modality, based on updated concepts of patient-centered prescription and adequacy in dialytic renal replacement therapies.

Peritoneal membrane status, clinical data and aging-related molecules were investigated as predictors of long-term peritoneal dialysis (PD) outcomes. A 5-year prospective study was conducted with the following endpoints: (a) PD failure and time until PD failure, (b) major cardiovascular event (MACE) and time until MACE. A total of 58 incident patients with peritoneal biopsy at study baseline were included. Peritoneal membrane histomorphology and aging-related indicators were assessed before the start of PD and investigated as predictors of study endpoints. Fibrosis of the peritoneal membrane was associated with MACE occurrence and earlier MACE, but not with the patient or membrane survival. Serum α-Klotho bellow 742 pg/mL was related to the submesothelial thickness of the peritoneal membrane. This cutoff stratified the patients according to the risk of MACE and time until MACE. Uremic levels of galectin-3 were associated with PD failure and time until PD failure. This work unveils peritoneal membrane fibrosis as a window to the vulnerability of the cardiovascular system, whose mechanisms and links to biological aging need to be better investigated. Galectin-3 and α-Klotho are putative tools to tailor patient management in this home-based renal replacement therapy.

Introduction: Exit-site infection (ESi) prevention is a key factor in lowering the risk of peritonitis. This study aimed to evaluate the associations between exit-site (ES) care protocols and the annual incidence rates of ESi and peritonitis in Portugal. Methods: We performed a national survey using two questionnaires: one about the incidence of catheter-related infections and the other characterizing patients’ education and ES care protocols. Results: In 2017 and 2018, 14 Portuguese units followed 764 and 689 patients. ESi incidence rate was 0.41 episodes/year, and the peritonitis incidence rate was 0.37. All units monitor catheter-related infections on a yearly basis, use antibiotic prophylaxis at the time of catheter placement, and treat nasal carriage of S. aureus, although with different approaches. Screening for nasal carriage of S. aureus is performed by 12 units, and daily topical antibiotic cream is recommended by 6 out of 14 of the units. We did not find statistical differences in ESi/peritonitis, comparing these practices. The rate of ESis was lower with nonocclusive dressing immediately after catheter insertion, bathing without ES dressing, with the use of colostomy bags in beach baths and was higher with the use of bath sponge. The peritonitis rate was lower with bathing without ES dressing and if shaving of the external cuff was performed in the presence of chronic ESi. Conclusions: We found potential proceedings associated with ESi and peritonitis. A regular national audit of peritoneal dialysis units is an important tool for clarifying the best procedures for reduction of catheter-related infections.