Background: Intraperitoneal pressure (IPP) may influence ultrafiltration (UF) in peritoneal dialysis (PD), but its clinical relevance under standard peritoneal equilibration test (PET) with 4.25%/3.86% dextrose remains uncertain. Methods: In 96 unselected PD patients, we performed two 4.25%/3.86% PETs using 1L and 2L fill volumes. IPP, UF, glucose UF efficiency, sodium dip (Na-Dip) as a marker of free water transport (FWT), osmotic conductance to glucose (OCG), and solute transport parameters (D/P _Creatinine and diffusion capacities (PS)) were assessed. Associations between IPP, UF parameters, and UF-related abnormalities were analyzed. Results: The 2L PET showed higher IPP, dialysate glucose concentration, and PS, and lower D/P _Creatinine , as expected. However, an increase in water transport was not consistent: 21%, 66%, 29%, and 40% of patients showed in the 1L PET, respectively, higher UF, glucose UF efficiency, OCG, and Na-Dip. In 2L PET IPP was negatively correlated with UF ( r = −0.221; p = 0.03) and Na-Dip ( r = −0.210, p = 0.041). About 56% of patients presented at least one of the UF-related abnormalities identified (paradoxically higher UF with 1L, UF insufficiency (UF < 400 mL in 2L PET), and impaired FWT (Na-Dip≤5 mmol/L in 2L PET)). These patients had significantly higher IPP and reduced abdominal distensibility. Conclusions: This study shows an association between IPP and UF in 4.25%/3.86% dextrose PET that appears clinically relevant. It also raises the hypothesis that IPP may be related to FWT in PD. These findings highlight the importance of IPP monitoring in PD and the need for further studies to characterize changes in FWT across variations in volume and intraperitoneal pressure.

Background/Objectives: Frailty is increasingly recognized as a major determinant of adverse outcomes in patients receiving peritoneal dialysis (PD), yet it is not routinely incorporated into clinical practice. Because PD relies heavily on patient autonomy and self-management, frailty, sarcopenia, malnutrition, and impaired quality of life may compromise both outcomes and technique retention. This study aimed to describe current clinical practices related to frailty-informed assessment in PD units participating in the GCDP network and to identify barriers to implementing a more comprehensive, patient-centered approach. Methods: We conducted a descriptive, observational, cross-sectional study based on a survey distributed to PD units belonging to the Grupo Centro de Diálisis Peritoneal (GCDP), a collaborative network of 24 hospitals across four autonomous communities in Spain. Physicians and nurses completed the questionnaire between January and February 2025. The survey explored seven domains: use of frailty scales, nutritional screening tools, dynamometry, muscle ultrasound, bioimpedance, quality of life instruments, and digital applications for patient follow-up. Results: Twenty of 24 centers completed the survey. Although all units considered frailty clinically relevant, only 11 assessed it at PD initiation and only 5 performed periodic or systematic re-evaluation. Nutritional screening tools were used in 13 centers, most commonly the Malnutrition Inflammation Score. Twelve centers had a dynamometer, though its use was not standardized. All centers used bioimpedance—primarily for hydration assessment—while muscle ultrasound was rarely applied in scheduled follow-up. Only 7 centers assessed quality of life. The main reported barriers were lack of time in routine practice and the absence of specific guidelines and training. Conclusions: Frailty-related assessment across participating GCDP units remains heterogeneous and incompletely implemented despite broad recognition of its clinical relevance. The identified gaps in standardized protocols, training, and integration of assessment tools highlight priorities for future implementation research aimed at incorporating frailty-informed, patient-centered assessment into routine PD care.