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. 2023 Feb 22;8(5):1022-1033.
doi: 10.1016/j.ekir.2023.02.1078. eCollection 2023 May.

Proteinuria Modifies the Relationship Between Urinary Sodium Excretion and Adverse Kidney Outcomes: Findings From KNOW-CKD

Hyo Jeong Kim  1   2 , Chan-Young Jung  1   3 , Hyung Woo Kim  1 , Jung Tak Park  1 , Tae-Hyun Yoo  1 , Shin-Wook Kang  1 , Sue K Park  4   5   6 , Yeong Hoon Kim  7 , Su Ah Sung  8 , Young Youl Hyun  9 , Kook-Hwan Oh  10 , Seung Hyeok Han  1
Affiliations

Proteinuria Modifies the Relationship Between Urinary Sodium Excretion and Adverse Kidney Outcomes: Findings From KNOW-CKD

Hyo Jeong Kim et al. Kidney Int Rep. .

Abstract

Introduction: High sodium intake is associated with increased proteinuria. Herein, we investigated whether proteinuria could modify the association between urinary sodium excretion and adverse kidney outcomes in patients with chronic kidney disease (CKD).

Methods: In this prospective observational cohort study, we included 967 participants with CKD stages G1 to G5 between 2011 and 2016, who measured 24-hour urinary sodium and protein excretion at baseline. The main predictors were urinary sodium and protein excretion levels. The primary outcome was CKD progression, which was defined as a ≥50% decline in the estimated glomerular filtration rate (eGFR) or the onset of kidney replacement therapy.

Results: During a median follow-up period of 4.1 years, the primary outcome events occurred in 287 participants (29.7%). There was a significant interaction between proteinuria and sodium excretion for the primary outcome (P = 0.006). In patients with proteinuria of <0.5 g/d, sodium excretion was not associated with the primary outcome. However, in patients with proteinuria of ≥0.5 g/d, a 1.0 g/d increase in sodium excretion was associated with a 29% higher risk of adverse kidney outcomes. Moreover, in patients with proteinuria of ≥0.5 g/d, the hazard ratios (HRs) (95% confidence intervals[CIs]) for sodium excretion of <3.4 and ≥3.4 g/d were 2.32 (1.50-3.58) and 5.71 (3.58-9.11), respectively, compared with HRs for patients with proteinuria of <0.5 g/d and sodium excretion of <3.4 g/d. In sensitivity analysis with 2 averaged values of sodium and protein excretion at baseline and third year, the results were similar.

Conclusion: Higher urinary sodium excretion was more strongly associated with an increased risk of adverse kidney outcomes in patients with higher proteinuria levels.

Keywords: chronic kidney disease; kidney function decline; nutrition; proteinuria; salt intake; urinary sodium excretion.

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Figures

None
Graphical abstract
Figure 1
Figure 1
Flow diagram of the study cohort. KNOW-CKD, Korean Cohort Study for Outcome in Patients with CKD.
Figure 2
Figure 2
Cumulative incidence curve for primary outcomes according to the baseline 24-hour urinary sodium and protein excretion.
See this image and copyright information in PMC

Comment in

References

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