title: Urinary sodium excretion and kidney failure in nondiabetic chronic kidney disease.
abstract: Current guidelines recommend under 2 g/day sodium intake in chronic kidney disease, but there are a few studies relating sodium intake to long-term outcomes. Here we evaluated the association of mean baseline 24-h urinary sodium excretion with kidney failure and a composite outcome of kidney failure or all-cause mortality using Cox regression in 840 participants enrolled in the Modification of Diet in Renal Disease Study. Mean 24-h urinary sodium excretion was 3.46 g/day. Kidney failure developed in 617 participants, and the composite outcome was reached in 723. In the primary analyses, there was no association between 24-h urine sodium and kidney failure (HR 0.99 (95% CI 0.91-1.08)) nor on the composite outcome (HR 1.01 (95% CI 0.93-1.09)), each per 1 g/day higher urine sodium. In exploratory analyses, there was a significant interaction of baseline proteinuria and sodium excretion with kidney failure. Using a two-slope model, when urine sodium was under 3 g/day, higher urine sodium was associated with increased risk of kidney failure in those with baseline proteinuria under 1 g/day and with lower risk of kidney failure in those with baseline proteinuria of ⩾ 1 g/day. There was no association between urine sodium and kidney failure when urine sodium was ⩾ 3 g/day. Results were consistent using first baseline and time-dependent urinary sodium excretion. Thus, we noted no association of urine sodium with kidney failure. Results of the exploratory analyses need to be verified in additional studies and the mechanism explored.
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, Massachusetts, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Fan
authors.affiliation: Research Design Center/ Biostatistics Research Center, Tufts Clinical and Translational Science Institute (CTSI), Tufts Medical Center, Boston, Massachusetts, USA.
authors.forename: Hocine
authors.initials: H
authors.lastname: Tighiouart
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, Massachusetts, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Levey
authors.affiliation: Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Beck
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, Massachusetts, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarnak
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005919:Glomerular Filtration Rate; D005921:Glomerulonephritis / Q000150:complications / Q000401:mortality / Q000652:urine*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000209:etiology / Q000401:mortality / Q000652:urine*; D008297:Male; D008875:Middle Aged; D007690:Polycystic Kidney Diseases / Q000150:complications / Q000401:mortality / Q000652:urine*; D011379:Prognosis; D011507:Proteinuria / Q000652:urine; D012964:Sodium / Q000652:urine*; D012982:Sodium, Dietary
chemical_list: D012982:Sodium, Dietary; D012964:Sodium