Abstract

SILVA, Otávio Marcos da et al. Comparative study of spot urine Na/K ratio and 24-hour urine sodium in natriuresis evaluation of cirrhotic patients with ascites. J Port Gastrenterol. [online]. 2014, vol.21, n.1, pp.15-20. ISSN 0872-8178.  https://doi.org/10.1016/j.jpg.2013.04.006.

Introduction: The ‘‘spot’’ urine sodium/potassium (Na/Ku) ratio is a convenient tool to identify sodium excretion < 78 mequiv./d. It has been established that this ratio is as useful and accurate as 24-h urine sodium (Nau24h), but no Latin American study has evaluated this issue. The aim of this study is to evaluate the accuracy of the Na/Ku ratio and to compare it to Nau24h. Materials and methods: This cross-sectional study included 20 patients with decompensated liver cirrhosis and ascites. Results:Mean age was 56.1±11.8 years old, 70% were men and 60% presented Nau24h < 78 mequiv./d. Poor sodium excretion group presented higher MELD score (P = 0.002), creatinine (P = 0.029), AST (P = 0.027) and bilirubin (P = 0.013) levels, and also lower median spot sodium urine (P = 0.001). There was a high positive correlation between Na/Ku ratio and Nau24h (r = 0.857; P < 0.001) and negative correlation with MELD (r =−0.498; P = 0.025) and sérum creatinine (r =−0.498; P = 0.025). The AUROC of Na/Ku in predicting Nau24h < 78 mequiv./d was 0.948±0.046 and the classical Na/Ku ratio cut-off (≤1.0) showed PPV = 70%, NPV = 90%, accuracy = 80%, sensitivity = 88% and specificity = 75%. Conclusion: Na/Ku ≤1 is sensitive and specific, and substantially correlates with Nau24h, which enables the use of this test in the routine evaluation of patients with liver cirrhosis decompensated in ascites.

Keywords : Liver cirrhosis; Ascites; Sodium; Urine; End stage liver disease.

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