The recommended starting dose of Tolvaptan for heart failure (HF) is 7.5 mg/day in Japan; the recommended dose is 3.75 mg/day for older patients to avoid excessive diuresis and hypernatremia. However, low-dose Tolvaptan may delay the release of congestion in some patients. We aimed to develop a score to predict treatment responders to 3.75 mg tolvaptan.We retrospectively analyzed 106 patients with HF who initially received 3.75 mg/day of Tolvaptan in the derivation cohort (April 2013-December 2017) and 63 patients receiving 3.75 mg/day of Tolvaptan in the validation cohort (January 2018-April 2021). Treatment responders to 3.75 mg tolvaptan did not require dose escalation of Tolvaptan for congestion relief. In multivariate analysis, blood urea nitrogen (BUN) < 39 mg/dL and hematocrit > 35% were selected as variables to predict treatment responders. These were assigned 1 point each, and patients were stratified into groups with 2 points (n = 32), 1 point (n = 39), and 0 points (n = 35). The frequency of treatment responders was 82.9% in the 2-point group, 61.5% in the 1-point group, and 34.4% in the 0-point group (P < 0.05). The predictive ability of the score was acceptable with an area under the receiving operator characteristic curve (AUC) 0.726 (P < 0.05); its performance was maintained in the validation cohort (AUC 0.733, P < 0.05).A simple score using BUN and hematocrit could identify treatment responders to 3.75 mg tolvaptan, which may help determine the appropriate starting dose of Tolvaptan, balancing efficiency with safety for older patients with HF.
Keywords: Blood urea nitrogen; Diuresis; Hematocrit; Treatment responder.