Estimation of salt intake from spot urine samples in patients with chronic kidney disease

BMC Nephrology

Research Article

Masatsugu Nakao¹  Koki Takane¹  Akihiko Hamaguchi¹  Tatsuo Hosoya¹  Hiroyuki Terawaki¹  Ai Kimura¹  Makoto Ogura² 

[1] Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-19-18, Nishi-shinbashi, 105-8471, Minato-ku, Tokyo, Japan;null;

关键词: Chronic kidney disease;    Salt intake;    Urinary sodium excretion;   

DOI  :  10.1186/1471-2369-13-36

 received in 2011-08-21, accepted in 2012-05-21,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundHigh salt intake in patients with chronic kidney disease (CKD) may cause high blood pressure and increased albuminuria. Although, the estimation of salt intake is essential, there are no easy methods to estimate real salt intake.MethodsSalt intake was assessed by determining urinary sodium excretion from the collected urine samples. Estimation of salt intake by spot urine was calculated by Tanaka’s formula. The correlation between estimated and measured sodium excretion was evaluated by Pearson´s correlation coefficients. Performance of equation was estimated by median bias, interquartile range (IQR), proportion of estimates within 30% deviation of measured sodium excretion (P30) and root mean square error (RMSE).The sensitivity and specificity of estimated against measured sodium excretion were separately assessed by receiver-operating characteristic (ROC) curves.ResultsA total of 334 urine samples from 96 patients were examined. Mean age was 58 ± 16 years, and estimated glomerular filtration rate (eGFR) was 53 ± 27 mL/min. Among these patients, 35 had CKD stage 1 or 2, 39 had stage 3, and 22 had stage 4 or 5. Estimated sodium excretion significantly correlated with measured sodium excretion (R = 0.52, P < 0.01). There was apparent correlation in patients with eGFR <30 mL/min (R = 0.60, P < 0.01). Moreover, IQR was lower and P30 was higher in patients with eGFR < 30 mL/min. Estimated sodium excretion had high accuracy to predict measured sodium excretion, especially when the cut-off point was >170 mEq/day (AUC 0.835).ConclusionsThe present study demonstrated that spot urine can be used to estimate sodium excretion, especially in patients with low eGFR.

【 授权许可】

Unknown   
© Ogura et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.