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 x{2x[(urine sodium (mEq/L)]+ [urine urea nitrogen (mg/dl)]/2.8+ [urine creatinine (mg/dl)] x2/3}+16, was well correlated with the actual measurement (r=0.938, P<0.001). Criteria consisting of Cl (estimated baseline U-OSM >358 mOsm/L) and C2 (%decrease in estimated U-OSM >24% at 4-6h 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. (Circ J 2013; 77: 1208-1213)