Lithium treatment reduces hospitalization risk due to hyponatremia, finds study
Sweden: Electrolyte disturbances are frequent, with up to 30% of hospitalized patients having hyponatraemia.
Lithium therapy may decrease the risk of hospitalization due to hyponatremia, according to a recent study in the Journal of Psychopharmacology.
Hyponatremia, a condition of low sodium levels in the blood, is a potentially serious disorder, that affects up to 30% of hospitalized patients. Symptoms include lethargy, agitation, confusion, seizures, coma and death.
Many drugs used in psychiatric care have been reported to cause hyponatremia. However, lithium is one such drug used in psychiatry that may reduce hyponatremia risk due to its potential for causing nephrogenic diabetes insipidus, but clinical data are largely absent. Henrik Falhammar, Karolinska Institutet, Stockholm, Sweden, and colleagues studied the association between lithium therapy and hospitalization due to hyponatremia.
In this case-control investigation of the general Swedish population, the researchers compared 11,213 patients hospitalized with a principal diagnosis of hyponatremia with 44,801 matched controls. To calculate the association between severe hyponatremia and the use of lithium, analyses using multivariable logistic regression adjusting for co-medication, diseases, previous hospitalizations, and socioeconomic factors were deployed. Additionally, newly initiated (90 days) and ongoing lithium therapy was studied separately.
Key findings of the study include:
- Compared with controls, the unadjusted odds ratio (OR) (95% confidence interval (CI)) for hospitalization due to hyponatraemia was 1.07 for lithium.
- After adjustment for confounding factors the risk was reduced (adjusted OR: 0.53).
- Newly initiated lithium therapy was not significantly associated with hyponatraemia (adjusted OR 0.73).
- For ongoing therapy the corresponding adjusted OR was significantly reduced (adjusted OR: 0.52).
The researchers found a marked inverse association between lithium therapy and hospitalization due to hyponatremia. The most liked mechanics involved is lithium-induced nephrogenic diabetes insipidus. The main clinical implication of this study is that lithium treatment is an unlikely cause of hyponatremia.
"This is the first population-based study reporting on lithium therapy and hyponatremia. The association with hyponatremia requiring hospitalization was halved in individuals treated with lithium," concluded the authors.
"Reduced risk for hospitalization due to hyponatraemia in lithium treated patients: A Swedish population-based case–control study," is published in the Journal of Psychopharmacology.