Neurologic and psychiatric disorders following correction of profound hyponatremia - A cohort study.

Background: Rapid correction of profound hyponatremia (serum sodium <125 mmol/L) has been associated with osmotic demyelination syndrome (ODS) but this has been challenged. Potential associations with other neurological and psychiatric diseases have not been studied.

Methods: The basis of this study was the Stockholm Sodium Cohort, a laboratory data repository covering inhabitants of the Stockholm Region who had a sodium concentration analyzed (2005-2018, n = 1632,249). Patients admitted with profound hyponatremia for the first time during the study period where sodium correction rates during the first 24 h could be calculated were included. Sodium correction ≤8 and >8 mmol/L/24 h was compared.

Results: Hospitalization with profound hyponatremia occurred in 7623 individuals, 3199 (42.0 %) were males, and the median age was 70 years (IQR 59-80 years). Alcohol misuse was present in 18.3 %, a neurological and/or psychiatric disease in 52.4 % and hypokalemia in 27.9 %. The recommended correction rate ≤8 mmol/L/24 h was adhered to in 3985 (52.3 %) patients. Seven patients (0.09 %) were diagnosed with ODS, six had a correction rate >8 mmol/L/24 h (compared to 1 patient with a correction rate ≤8 mmol/L, P = 0.0441). The risk of new neurological or psychiatric diseases did not differ significantly between those with a correction rate ≤8 mmol/L/24 h and those above in the fully adjusted model (adjusted hazard ratio 1.02 95 %CI 0.89-1.17)) nor in the subgroups.

Conclusions: ODS was rare, however, mainly associated with rapid correction. Consequently, slow correction may be preferable.