Tolvaptan treatment in hyponatremia due to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH): effects on survival in patients with cancer

Purpose To investigate the clinical outcomes of patients with hyponatremia who received supportive treatment or tolvaptan plus supportive treatment and the effects of treatment and other variables on overall survival Methods This study included oncology patients who were hospitalized at two oncology centers between January 1, 2016 and December 31, 2019 for hyponatremia (sodium levels < 135 mEq/L) and who received tolvaptan plus supportive treatment (n = 22) or supportive treatment only (n = 42). Results The median age of all the patients was 59 years (range 26-85) and 64.1% of the patients were male. There was no statistically significant difference between patients in the tolvaptan plus supportive treatment (TpST) group and the supportive treatment only (ST) group in terms of gender and age (p > 0.05). In the TpST group, recovery days of the hyponatremia after treatment and the length of hospital stay was shorter and hyponatremia symptoms and hospital complications were less frequent compared to the ST group (p < 0.05). There was no significant difference between the TpST group and the ST group in terms of overall survival (OS). OS was shorter in men who were non-responders to hyponatremia treatment and had recurrent hyponatremia. Multivariable analysis showed that normal sodium levels after treatment decreased the risk of death. Conclusion In the treatment of hyponatremia in cancer patients, TpST was found to have more positive effects on blood sodium levels, length of hospital stay, hospital complications, and hyponatremia symptoms compared to ST. A decreased risk of death was observed in patients with normal sodium levels after treatment.