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 3.75–15mg/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 358mOsm/L) and C2 (%decrease in estimated U-OSM >24% at 4–6h after the first TLV dose) significantly discriminated responders from non-responders (P