#4202 FLUID OVERLOAD AT THE BEGINNING OF PERITONEAL DIALYSIS: A CROSS-SECTIONAL STUDY TO DETERMINE ITS ASSOCIATION WITH SERUM BIOMARKERS Free

Volume management in peritoneal dialysis (PD) patients is of major importance as fluid overload has been associated with cardiovascular and non-cardiovascular morbidity and mortality. Clinical examination itself has a poor diagnostic accuracy for minor deviations from normohydration, highlighting the need of additional tools. The aim of this study was to evaluate the association between serum biomarkers (CA-125 and NT-proBNP) and volume status, evaluated by clinical and bioimpedance analysis, at the initiation of PD technique.

Single-center cross-sectional study including PD patients that started technique between 2017 and 2022. Demographic and clinical data were collected from the electronic records. Parameters evaluated were clinical examination, serum biomarkers, bioimpedance and dialysis adequacy.

A total of 79 patients (51 male) were included with a mean age of 57±15 years. All of them started with CAPD and 52% were under icodextrin. Hypertension, cardiovascular disease and diabetes were present in 94%, 51% and 34%, respectively. The great majority were under renin-angiotensin-aldosterone system inhibitors (91%), beta-blockers (48%) and diuretic therapy (94%). Baseline PET showed that 77% were high or high-average transporters. Mean weekly Kt/V was 2.4±15. The mean residual renal function (RRF) and residual diuresis were 6.7±15 mL/min/1.73 m² and 1.6±0.8 L (4% anuric), respectively, and 11% had ultrafiltration failure. Median nPCR was 0.9 g/Kg/day (IQR 0.3). Median NT-proBNP and CA-125 were 1337 pg/mL (IQR 3401) and 14.6 U/mL (IQR 17.6), respectively. NT-proBNP was positively associated with overhydration (OH >2 L) (r = 0.31; p = 0.009), CA-125 (r = 0.28; p = 0.01) and icodextrin use (p = 0.002). It was negatively associated with weekly Kt/V (r = -0.35; p = 0.003), RRF (r = -0.36; p = 0.002), ultrafiltration test (UFT) (r = -0.35; p = 0.003) and nPCR (r = -0.28; p = 0.001). CA-125 was positively associated with higher overhydration (OH > 3.6 L), D/P creatinine (r = 0.3; p = 0.004) and icodextrin use (p = 0.001). It was negatively associated with weekly Kt/V (r = -0.3; p = 0.01), UFT (r = -0.25; p = 0.03) and nPCR (r = -0.23; p = 0.04). NT-proBNP was still associated with overhydration in a multivariable analysis, adjusted to diabetes, icodextrin use, RRF and CA-125 (p = 0.024).

Serum NT-proBNP and CA-125 seem to be good markers of overhydration at PD baseline. They were also associated with worse dialytic efficacy and ultrafiltration, lower residual renal function and an early need of icodextrin use. Malnourished patients were associated with higher NT-proBNP and CA-125. Early and effective management of hydration may improve clinical outcomes, allowing personalized dialysis prescription and nutritional support.