MO689: Relationship between Peritoneal/Renal Function and Nutritional Status in Peritoneal Dialysis Patients
Authors: Donato Beatriz , Mateus Catarina , Adragao Teresa , Matias Patricia , Branco Patricia 
Published: May 2022

Abstract

BACKGROUND AND AIMS
The positive impact of nutritional status on the health and treatment adequacy of peritoneal dialysis (PD) patients has been well established. There are several accepted strategies for stratifying malnutrition in PD, such as laboratory markers [serum albumin and normalized protein catabolic ratio (nPCR)] and the recent use of bioimpedance spectroscopy (BIS). The aim of this study was to assess the nutritional status of PD patients upon the start of the therapy. We also aimed to establish a potential relationship between peritoneal/renal function, obtained by a peritoneal equilibration test (PET), and nutritional markers.

METHOD
We studied a cohort of patients from a single PD unit between 1 July 2011 and 31 August 2021, who had one BIS measurement and a PET in the first 3 months after the beginning of PD. We also collect laboratory data within 6 months from the BIS reading (albumin, C-reactive protein and phosphorus). Demographic parameters (age, dialysis vintage, presence or absence of diabetes mellitus) and body mass index were also evaluated.

RESULTS
The study included 91 incident PD patients. The mean age of patients was 65.40 $ \pm $ 13.88 years, 59.3% were male and 28% had diabetes. Regarding baseline renal and peritoneal parameters, weekly total kt/v median was 1.99 (IQR 0.99–2.59) residual renal function (eGFR) median 3.2 (IQR 2.12–7.75) mL/min/1.73 m2 daily diuresis median 1500 (IQR 1000–2100), fluid removal (FR) median 2.23 (IQR 1.86–2.65) L/day and 41.8% had a dialysate/plasma (D/P) creatinine higher than 0.77.
Lean tissue index was low in 36.3% and fat tissue index was high in 52.2%. Serum albumin median was 3.7 (IQR 3.3–4) g/dL and nPCR median 0.84 (IQR 0.72–1.04) g/kg/day. Hypervolemic patients had significantly lower lean tissue index (13.77 ± 3.25 versus 16.87 ± 3.82, P = 0.003). In a univariate analysis, patients with nPCR &lt; 1.2 g/kg/day (79.1% from the complete cohort with no age difference) had lower baseline weekly total kt/v (2.17 ± 0.43 versus 6.62 ± 4.45, P &lt; 0.001, lower daily diuresis (1261 ± 753 versus 1687 ± 958, P = 0.047), lower FR (2.05 ± 0.57 versus 2.40 ± 0.80, P = 0.043), and also significantly lower D/P creatinine (0.74 ± 0.1 versus 0.97 ± 0.27, P &lt; 0.001). Furthermore, patients with serum albumin &lt;3.8 g/dL had a lower ultrafiltration proof (326 ± 192 versus 511 ± 267, P = 0.028) and those with low lean tissue index had a lower daily diuresis (1405 ± 825 versus 1823 ± 1025, P = 0.045). In a multivariate analysis, patients with nPCR &lt; 1.2 g/kg/day were older [exp (B) 0.19, 95% CI 0.8–0.9, P = 0.012] and had lower weekly total kt/v [exp (B) 0.18, 95% CI 0.6–0.9, P = 0.017].

CONCLUSION
This study showed some relationships between kidney/peritoneal function parameters and body composition parameters. The level of nPCR, a measure of nutritional status, was significantly and positively associated with indicators of dialysis adequacy (kt/v), daily diuresis and, also with transport type. Further research regarding nutrition must be undertaken to help improve health outcomes in PD patients.