Introduction: Arginine vasopressin-stimulated reabsorption of urea occurs in the collecting duct via increased expression of the urea transporter.
Objective: The aim of this study was to evaluate whether the blood urea nitrogen/creatinine (BUN/Cr) ratio is useful for predicting tolvaptan response in patients with decompensated heart failure (HF).
Methods: Among 71 consecutive patients with HF who received oral tolvaptan between 2010 and 2014, we retrospectively studied 33 patients with decompensated HF without any mechanical circulatory assistance or inotropic support who had already been treated with loop diuretics. A responder to tolvaptan was defined as an individual who experienced a ≥30 % increase in their respective 24-h urine volume.
Results: Among the 33 patients, 21 met the criteria of a responder. The area under the receiver operating characteristic curves of BUN/Cr and BUN were 0.790 and 0.714, respectively, and the respective cut-off values for responders to tolvaptan were 23.8 and 49.0. BUN/Cr and BUN retained their significant relationships with the responder status (odds ratio for BUN/Cr >23.8: 20.9; 95 % confidence interval [CI] 2.7-531.1; p = 0.002; odds ratio for BUN ≥49: 7.7; 95 % CI 1.4-65.8; p = 0.02).
Conclusion: Our results suggest that high BUN/Cr may be a predictor of response to tolvaptan in decompensated HF patients. A prospective study with a large sample size is required to confirm this preliminary finding.