Background: During chemotherapy, hyponatremia is one of the most frequently encountered adverse effects. This study aimed to investigate the prognostic impact of hyponatremia induced by systemic chemotherapy (HIC) using a propensity matching method in cumulative pooled data.
Methods: Between January 2011 and July 2017, 2129 patients were administered systemic chemotherapy for malignancy in various organs at Nagoya City University Hospital. Patients were divided into two groups: a grade 0-1 group (control group) and a grade 3-4 group (severe group) according to the severity of HIC appearing within 30 days after starting treatment. Kaplan-Meier curves were used for survival and recurrence analyses using a propensity case-matched analysis.
Result: The number of severe HIC patients was 93 (4.4%). In platinum-containing regimens, HIC appeared at higher frequencies. In the 21.2 months median follow-up period, the median OS (mOS) in the severe group was 49.1 months, which was significantly worse than the mOS in the control group; the OS in the control group did not reach the median. Univariate and multivariate analyses of associated factors in patients with grade 3-4 HIC revealed that renal dysfunction, cisplatin-containing regimen, and infusion of more than 5000 mL fluid was associated with HIC.
Conclusion: This study suggests that severe HIC in the first treatment cycle affects survival time. Chemotherapy patients receiving extensive hydration should be required to undergo frequent monitoring of serum sodium levels, especially patients receiving platinum-containing regimens.
Keywords: Chemotherapy; Hydration; Hyponatremia; Prognosis.