Beta-trace protein as a potential biomarker of residual renal function in patients undergoing peritoneal dialysis

BACKGROUND: Residual renal function is closely linked to quality of life, morbidity and mortality in dialysis patients. Beta-trace protein (BTP), a low molecular weight protein, has been suggested as marker of residual renal function, in particular in patients on hemodialysis. We hypothesized that BTP also serves as a marker of residual renal function in pertioneal dialysis patients. METHODS: In this study 34 adult patients on peritoneal dialysis were included. BTP, creatinine, cystatin C and urea concentrations were analyzed simultaneously in serum and dialysate to calculate renal and peritoneal removal of the analytes. RESULTS: In peritoneal dialysis patients with residual diuresis, mean serum BTP was 8.16 mg/l (SD ± 4.75 mg/l). BTP correlated inversely with residual diuresis (r(s) = − 0.58, p < 0.001), residual creatinine clearance (Cl(Cr)) (r(s) = − 0.69, p < 0.001) and total urea clearance (Cl(urea)) (r(s) = − 0.56, p < 0.001). Mean peritoneal removal of BTP was 3.36 L/week/1.73m(2) (SD ± 1.38) and mean renal removal 15.14 L/week/1.73m(2) (SD ± 12.65) demonstrating a significant renal contribution to the total removal. Finally, serum BTP inversely correlated with alterations in residual diuresis (r = − 0.41, p = 0.035) and renal creatinine clearance over time (r = − 0.79, p = p < 0.001). CONCLUSION: BTP measurement in the serum may be a simple tool to assess residual renal function in peritoneal dialysis patients.