Overcorrection of plasma sodium in severe hyponatremia is associated with osmotic demyelination syndrome. Desmopressin (DDAVP) can prevent overcorrection of plasma sodium in hyponatremia. The objective of this study was to compare outcomes in hyponatremia according to DDAVP usage.

This was a retrospective observational study including all admissions to internal medicine with hyponatremia (plasma sodium concentration <123 mEq/L) from 2004 to 2014 at 2 academic hospitals in Toronto, Canada. The primary outcome was safe sodium correction (≤12 mEq/L in any 24-hour and ≤18 mEq/L in any 48-hour period).

We identified 1450 admissions with severe hyponatremia; DDAVP was administered in 254 (17.5%). Although DDAVP reduced the rate of change of plasma sodium, fewer patients in the DDAVP group achieved safe correction (174 of 251 [69.3%] vs 970 of 1164 [83.3%]); this result was driven largely by overcorrection occurring before DDAVP administration in the rescue group. Among patients receiving DDAVP, most received it according to a reactive strategy, whereby DDAVP was given after a change in plasma sodium within correction limits (174 of 254 [68.5%]). Suspected osmotic demyelination syndrome was identified in 4 of 1450 admissions (0.28%). There was lower mortality in the DDAVP group (3.9% vs 9.4%), although this is likely affected by confounding. Length of stay in hospital was longer in those who received DDAVP according to a proactive strategy.

Although observational, these data support a reactive strategy for using DDAVP in patients at average risk of osmotic demyelination syndrome, as well as a more stringent plasma sodium correction limit of 8 mEq/L in any 24-hour period for high-risk patients. Further studies are urgently needed on DDAVP use in treating hyponatremia.