Changes in Urinary Potassium Excretion in Patients with Chronic Kidney Disease

• Published in: Kidney research and clinical practice Vol. 35; no. 2; pp. 78 - 83
• Main Authors: Ueda, Yuichiro, Ookawara, Susumu, MD, PhD, Ito, Kiyonori, Miyazawa, Haruhisa, Kaku, Yoshio, Hoshino, Taro, Tabei, Kaoru, Morishita, Yoshiyuki
• Format: Journal Article
• Language: English
• Published: Korea (South) Elsevier B.V 01.06.2016; Elsevier; The Korean Society of Nephrology; 대한신장학회
• Subjects: Chronic kidney disease; Estimated glomerular filtration rate; Nephrology; Original; Urinary potassium excretion; 내과학; Urinary potassium excretion; Estimated glomerular filtration rate; Chronic kidney disease
• ISSN: 2211-9132; 2211-9140
• DOI: 10.1016/j.krcp.2016.02.001

Abstract Background Hyperkalemia is one of the more serious complications of chronic kidney disease (CKD), and the cause of potassium retention is a reduction in urinary potassium excretion. However, few studies have examined the extent of the decrease of urinary potassium excretion in detail with respect to decreased renal function. Methods Nine hundred eighty-nine patients with CKD (CKD stages G1 and G2 combined: 135; G3a: 107; G3b: 170; G4: 289; G5: 288) were evaluated retrospectively. Values for urinary potassium excretion were compared between CKD stages, and the associations between urinary potassium excretion and clinical parameters, including diabetes mellitus (DM) status and use of renin-angiotensin-aldosterone system (RAAS) inhibitors, were analyzed using a multivariable linear regression analysis. Results Urinary potassium excretion gradually decreased with worsening of CKD (G5: 24.8 ± 0.8 mEq/day, p < 0.001 vs. earlier CKD stages). In contrast, the value of fractional excretion of potassium at CKD G5 was significantly higher than those at the other stages (30.63 ± 0.93%, p < 0.001). Multivariable linear regression analysis revealed that urinary potassium excretion was independently associated with urinary sodium excretion (standardized coefficient: 0.499), the estimated glomerular filtration rate (eGFR, 0.281), and serum chloride concentration (-0.086). Conclusions This study demonstrated that urinary potassium excretion decreased with reductions in renal function. Furthermore, urinary potassium excretion was mainly affected by urinary sodium excretion and eGFR in patients with CKD, whereas presence of DM and use of RAAS inhibitors were not associated with urinary potassium excretion in this study.