Could serum CA125 aid the clinical assessment of volume status of end-stage kidney disease patients treated by peritoneal dialysis patients?

Introduction Volume overload is a major cause of technique failure, morbidity and mortality for peritoneal dialysis patients (PD). Biomarkers could potentially aid the clinical assessment of patients. Recently, Cancer antigen 125 (CA125) has been reported to predict volume status and outcomes in heart failure patients. As such we wished to evaluate CA125 in PD patients. Methods Serum CA125 was measured in patients attending for peritoneal membrane assessment, along with bioimpedance, N-terminal probrain natriuretic peptide (NT-proBNP), who had echocardiography measurements. Results Results from 571 PD patients, mean age 53.8±10.5 years 62.4% male, 44.0% diabetic, median PD treatment 2 (2-3) months were reviewed. Serum CA125 was higher in women vs men (25 (16-38) vs 17 (11-29) IU/L, p<0.05, Serum CA125 was positively associated with peritoneal solute transfer rates (PSTR) (r=0.35), extracellular water/intracellular water (ECW/ICW) (r=0.28), NT-proBNP (r=0.22), and negatively with left ventricular ejection fraction (r = -0.15), all p<0.001. Unlike other biomarkers there was no association with residual kidney function (r= -0.05 p=0.21). On multivariable analysis log CA125 was associated with female gender (standardised beta (Stꞵ) -0.224, PSTR Stꞵ 0.227, comorbidity score Stꞵ 0.16, serum sodium Stꞵ -0.146 all p<0.001, left ventricular ejection fraction Stꞵ -0.102, p=0.01, and ICW/ECW ratio Stꞵ 0.009, p=0.038). Conclusion Although serum CA125 values were higher in female patients, patients with higher CA125 levels had increased markers of volume overload or reduced left ventricular ejection fraction, in keeping with previous cardiology studies, and so serial measurements may potentially aid the clinical assessment of volume status in PD patients.