In patients with severe hyponatremia, faster correction of sodium levels is associated with a reduced risk of 90-day death or delayed neurologic events, according to a retrospective cohort study led by Dustin G. Mark, MD, of Kaiser Permanente, and colleagues. This finding appeared to be consistent across multiple subgroups and analytic approaches.
"Slow correction of severe hyponatremia is recommended to prevent osmotic demyelination syndrome but is associated with higher mortality," the researchers commented. However, the present analysis suggests that "treatment guidelines should be reexamined."
Study Details
The researchers focused on 13,988 patients (median age = 74 years; 63% female) with a serum sodium level of 120 mEq/L or lower who were hospitalized in 21 community hospitals within an integrated health system in northern California between 2008 and 2023. In this population, comorbidities included congestive heart failure (24%), liver disease (18%), alcohol dependence (14%), and metastatic cancer (10%).
In accordance with current guidelines for treating hyponatremia, 24-hour correction rates were classified as slow (less than 8 mEq/L), medium (8–12 mEq/L), or fast (greater than 12 mEq/L).
The primary outcome was a composite of 90-day death or delayed neurologic events, including new demyelination, paralysis, epilepsy, or altered consciousness occurring between 3 and 90 days after admission. Standardized risk differences were estimated using targeted maximum likelihood methods, and effect heterogeneity was evaluated across grades of predicted risk.
Key Findings
The researchers reported that the primary outcome occurred in 3,000 patients (21%), with 90-day death and delayed neurologic events occurring in 2,554 (18%) and 587 (4%), respectively. Medium and fast vs slow 24-hour sodium correction were associated with a 5.6 and 9.0 percentage point reduction in the adjusted risk of the primary outcome. Risk differences rose with higher predicted risk, the researchers noted, yet risk ratios remained similar.
Study limitations included residual confounding and the use of diagnostic codes for outcome ascertainment.
"Although some residual unmeasured confounding undoubtedly remains, the validity of these findings is supported by the relative strength of observed associations," the researchers concluded. "Given that multiple studies with varying designs have reached similar conclusions, treatment guidelines for severe hyponatremia should be reexamined to allow for faster sodium correction [for example, 8–12 mEq/L per 24 hours], regardless of presumed risk factors."
Disclosure: The study was funded by the Permanente Medical Group Rapid Analytics Unit Program. For full disclosures of the researchers, visit acpjournals.org.
Source: Annals of Internal Medicine
