(943) Evaluation of Sodium Correction With a Tolvaptan Order Set Within a Multi-Hospital Health System

Introduction: Hyponatremia is a complicated disease state, with treatment options guided by volume status and various lab parameters. Tolvaptan is a vasopressin-2 antagonist used for the treatment of hypervolemic or euvolemic hyponatremia. Manufacturer recommendations suggest avoiding fluid restrictions within the first 24 hours and initiating therapy for inpatients with close sodium monitoring. While prior literature suggested correction of rates of < 8mEq/L at 24hrs were appropriate for chronic hyponatremia, recent guidelines have updated recommendations with a more conservative approach targeting < 6mEq/L at 24 hours for safety. This study aimed to evaluate the current ordering patterns and sodium correction after tolvaptan administration within our health system.

Methods: This retrospective, multi-site, single health system study included adults who received tolvaptan between June 2015, and June 2024. Patients were divided into two groups based on orders for free water restriction vs. no restrictions. The primary outcome was the percentage of patients deemed to have overcorrected sodium, defined as a change in sodium > 6mEq/L within 24 hours or > 10mEq/L at 48 hours. Secondary outcomes included percent of patients overcorrected (defined via previous recommendations) with a change in sodium > 8mEq/L at 24 hours or > 12mEq/L at 48 hours, mean change in sodium at 24 hours and 48 hours, and resolution of hyponatremia (defined as > 130mEq/L or >135mEq/L at 48 hours).

Results: 874 patients met inclusion criteria and were evaluated. 430 patients were included in the restricted free water group and 444 patients in the no restriction group. The primary outcome was seen in 50% in the restricted group and 53.4% in the non-restricted group (p = 0.318). Change in sodium at 24 and 48 hours was similar between groups with an overall mean of 6.68 ± 4.6 and 7.49 ± 4.56 mEq/L, respectively. Resolution of hyponatremia was similar between groups with 5.6% of patients achieving a sodium of >135mEq/L at 48 hours and 40.6% achieving > 130mEq/L.

Conclusions: Current ordering patterns, regardless of the presence of fluid restriction, resulted in overcorrection at rates higher than what is considered safe in the literature. Predictive analysis and the current order set will be evaluated for future optimization and safety.