Association between the urinary sodium-to-potassium ratio and renal outcomes in patients with chronic kidney disease: a prospective cohort study

Yuta Matsukuma, Masaru Nakayama, Susumu Tsuda, Akiko Fukui, Ryota Yoshitomi, Kazuhiko Tsuruya, Toshiaki Nakano, Takanari Kitazono

Research output: Contribution to journalArticlepeer-review

Abstract

A higher urinary sodium-to-potassium (UNa/K) ratio has been reported to be associated with high blood pressure and subsequent cardiovascular events. However, the association between the UNa/K ratio and renal outcomes remains uncertain. We prospectively investigated the association between the UNa/K ratio and renal outcomes in patients with chronic kidney disease (CKD). We enrolled 716 patients with CKD, and 24-h urinary sodium and potassium excretion were measured. Patients were divided into UNa/K ratio tertiles (T1–T3). Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death and a composite of doubling of SCr or ESKD (added as an alternative outcome). We investigated the association between the UNa/K ratio and renal outcomes using a Cox proportional hazards model. During a median follow-up of 2.3 years, doubling of SCr, ESKD, or death and doubling of SCr or ESKD occurred in 332 and 293 patients, respectively. After adjustment for covariates including potentially confounding variables such as plasma renin activity, plasma aldosterone concentration, and B-type natriuretic peptide, the hazard ratios (HRs) (95% confidence intervals [CIs]) for the composite of doubling of SCr, ESKD, or death for T2 and T3 were 1.44 (1.06–1.96) and 1.59 (1.14–2.21), respectively, compared with T1. Additionally, compared with T1, the highest tertile (T3) of the UNa/K ratio was associated with a composite of doubling of SCr or ESKD (HR 1.55, 95% CI 1.09–2.20). A higher UNa/K ratio was independently associated with poor renal outcomes in patients with CKD.

Original languageEnglish
Pages (from-to)1492-1504
Number of pages13
JournalHypertension Research
Volume44
Issue number11
DOIs
Publication statusPublished - Nov 2021

All Science Journal Classification (ASJC) codes

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

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