The role of residual renal function on potassium intake and excretion in patients on peritoneal dialysis

• Published in: International urology and nephrology 2023-06, Vol.55 (6), p.1549-1556
• Main Authors: Claudino, Gabriele, Ramos, Christiane Ishikawa, de Andrade, Laila Santos, Pereira, Natalia Barros Ferreira, Teixeira, Renata Rodrigues, Muniz, Gisselma Aliny Santos, Di Medeiros Leal, Maria Carolina Bezerra, Cuppari, Lilian
• Format: Article
• Language: English
• Subjects: Anuria; Cross-Sectional Studies; Dialysate; Dialysis Solutions; Diuresis; Excretion; Feces; Female; Hemodialysis; Humans; Kidney - physiology; Kidney Failure, Chronic; Male; Medicine; Medicine & Public Health; Nephrology; Nephrology - Original Paper; Peritoneal Dialysis; Peritoneum; Potassium; Renal Dialysis; Renal function; Urology
• ISSN: 1573-2584; 0301-1623; 1573-2584
• DOI: 10.1007/s11255-023-03462-y

Background Patients on chronic dialysis are at increased risk of developing disorders in potassium balance. The preservation of residual renal function (RRF), frequently observed in patients on peritoneal dialysis (PD), may contribute to better control of serum potassium. This study aimed to investigate the role residual renal function on potassium intake and excretion in PD patients. Methods In this cross-sectional study, dietary potassium was evaluated by the 3-day food record. Potassium concentration was determined in serum, 24 h dialysate, stool ample, and 24 h urine of patients with diuresis > 200 mL/day, who were considered non-anuric. Results Fifty-two patients, 50% men, 52.6 ± 14.0 years, and PD vintage 19.5 [7.0–44.2] months, were enrolled. Compared to the anuric group ( n  = 17, 33%), the non-anuric group ( n  = 35, 67%) had lower dialysate potassium excretion (24.8 ± 5.3 vs 30.9 ± 5.9 mEq/d; p  = 0.001), higher total potassium intake (44.5 ± 16.7 vs 35.1 ± 8.1 mEq/d; p  = 0.009) and potassium intake from fruit (6.2 [2.4–14.7] vs 2.9 [0.0–6.0]mEq/d; p  = 0.018), and no difference in serum potassium (4.8 ± 0.6 vs 4.8 ± 0.9 mEq/L; p  = 0.799) and fecal potassium (2.2 ± 0.5 vs 2.1 ± 0.7 mEq/L; p  = 0.712). In non-anuric patients, potassium intake correlated directly with urinary potassium ( r  = 0.40; p  = 0.017), but not with serum, dialysate, or fecal potassium. In the anuric group, potassium intake tended to correlate positively with serum potassium ( r  = 0.48; p  = 0.051) and there was no correlation with dialysate or fecal potassium. Conclusion The presence of residual renal function constitutes an important factor in the excretion of potassium, which may allow the adoption of a less-restrictive diet.