NT-proBNP concentration in causes of hyponatremia Cause of hyponatremia CSWS (n=31) SIADH (n=47) p NT-proBNP (pg / ml) 420, 1± 285, 5 107, 1 ± 133, 1 <0, 005 Comment: NT-proBNP concentration in patients with hyponatremia due to CSWS (420.1 ± 285.5 pg / ml) was higher than in patients with hyponatremia due to SIADH (107.1 ± 133.1pg / ml) with statistical significance p <0.05.