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Urine osmolality estimated using urine urea nitrogen, sodium and creatinine can effectively predict response to
Teruhiko Imamura1, Koichiro Kinugawa, Shun Minatsuki
1Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
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.
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