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Hyponatremia correction is associated with increased brain-derived neurotrophic factor levels: A pilot secondary analysis of a randomized, double-blind, placebo-controlled, crossover trial

Kustos-Tóth E, Beck J, Seeger L, Monnerat S, Bathelt C, Refardt J, Christ-Crain M

Journal of neuroendocrinology, 2026

Abstract

Chronic hyponatremia is associated with cognitive deficits, yet the underlying mechanisms remain elusive. A cerebral growth factor which is crucial for cognition and memory is brain-derived neurotrophic factor (BDNF), but its role in hyponatremia has never been investigated. We here examined the influence of hyponatremia correction on serum BDNF levels. This study represents a secondary post hoc analysis of a prospective randomized, double-blind, crossover, placebo-controlled trial. Nine patients with syndrome of inappropriate antidiuresis (SIAD) completed 4 weeks treatments with empagliflozin 25 mg/day versus placebo. Serum sodium, BDNF levels, and Montreal Cognitive Assessment (MoCA) were assessed at baseline and after treatment cycles. Median baseline sodium was 131 mmol/L [130-133], which increased to 134 mmol/L ([131-136], p = .04) after empagliflozin treatment and remained stable after placebo phase (130 mmol/L [126-132], p = .9). Sodium increase was significantly associated with BDNF increase, also after adjusting for treatment arm, sex, age, baseline sodium, and antidepressant treatment (per 1 mmol/L sodium increase: estimate = 0.70 ng/mL, p = .048). This association was stronger upon empagliflozin treatment as shown by the interaction analysis (p = .03). In a subgroup of patients reaching normonatremia after empagliflozin treatment, BDNF increase was slightly higher compared to patients with persistent hyponatremia. MoCA scores did not differ between empagliflozin…

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Evidence Hub reads this as a secondary / pooled analysis, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

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