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Lower blood urea nitrogen affects response to Samsca in patients with cirrhosis

Blood urea nitrogen level and urinary sodium excretion correlated with response to Samsca, or tolvaptan, in patients with cirrhosis and hepatic edema, according to recently published data.

“In patients with hepatic edema, tolvaptan improves the hyponatremia that is frequently induced by conventional diuretics. However, not all cirrhotic patients with hepatic edema will response to or benefit from tolvaptan,” Masanori Atsukawa, MD, Nippon Medical School, Japan, and colleagues wrote. “The response to tolvaptan improved the survival rate in patients with lower [blood urea nitrogen (BUN)] levels, whereas it had no association with the survival rate in those with higher BUN levels.”

Atsukawa and colleagues retrospectively reviewed the data of 210 patients with cirrhosis and hepatic edema who received treatment with Samsca (tolvaptan, Otsuka Pharmaceuticals). At follow-up, 116 patients responded to therapy, and researchers observed a significant difference in BUN levels between responders and nonresponders (P = 3.77 x 10^-3).

Based on a cut-off value of 28.2 mg/dL BUN (AUC = 0.616), 61.7% of patients with a BUN level less than 28.2 mg/dL responded to therapy compared with 37.5% of those with a BUN level of 28.2 mg/dL or higher (P = 2.7 x 10^-3).

Patients who responded to therapy and had a BUN level less than 28.2 mg/dL had higher doses of spironolactone in previous therapy (P = 3.68 x 10^-4) and lower creatinine levels (P = 1.84 x 10^-9), compared with those with higher BUN levels.

In contrast, those with a BUN level of 28.2 mg/dL or higher had lower total bilirubin (P = 1.14 x 10^-2) and lower doses of spironolactone during previous therapy (P = 7.67 x 10^-3).

Multivariate analysis showed that BUN levels less than 28.2 mg/dL (OR = 3.75; 95% C, 1.01-12.53) and urinary sodium excretion of more than 51 mEq per day (OR = 2.86; 95% CI, 1.09-7.45) were independent factors for response to therapy with tolvaptan.

Compared with nonresponders, patients who responded to therapy had significantly higher survival rates (P = 1.9 x 10^-2). Survival rates were similar between patients with BUN levels less than 28.2 mg/dL and higher levels, and between responders and nonresponders with BUN levels 28.2 mg/dL or higher. However, among patients with a BUN level less than 28.2mg/dL, responders had significantly longer survival rates than nonresponders (P = 3.9 x 10^-3).

“It is unclear why responders with lower BUN levels showed favorable prognosis,” the researchers wrote. “This study was retrospective and included patients with hepatocellular carcinoma. A prospective study is needed to approve the effect of tolvaptan on the prognosis of cirrhotic patients with hepatic edema.” – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.