Urine osmolality estimated using urine urea nitrogen, sodium and creatinine can effectively predict response to tolvaptan in decompensated heart failure patients

Background: Urine osmolality (U-OSM) is valuable to predict response to tolvaptan (TLV) in decompensated heart failure patients, but measurement of U-OSM is not always available on site. Methods and Results: Data were collected from 66 hospitalized patients with decompensated heart failure who had received TLV at 3.75-15 mg/day. U-OSM, which was estimated using the following formula: 1.07 × {2 × [(urine sodium (mEq/L)] + [urine urea nitrogen (mg/dl)] / 2.8 + [urine creatinine (mg/dl) 2×/3} + 16, was well correlated with the actual measurement (r=0.938, P<0.001). Criteria consisting of C1 (estimated baseline U-OSM >358 mOsm/L) and C2 (%decrease in estimated U-OSM >24% at 4-6 h after the first TLV dose) significantly discriminated responders from non-responders (P<0.05). Conclusions: Response to TLV can be predicted using U-OSM, which can be estimated using urine urea nitrogen, sodium, and creatinine concentration data.