Prognosis of Cancer Patients with Severe Hyponatremia in the Emergency Department: A Retrospective Study from the National Cancer Center of China.

AIM: The aim of this study was to analyze the clinical characteristics and prognostic factors of profound hyponatremia in solid cancer patients admitted to the oncologic emergency department.

METHODS

We gathered data retrospectively from cancer patients who visited the emergency department of the National Cancer Center of China between October 2019 and February 2023 with a serum sodium (Na) level of less than 125 mmol/L. The demographic and clinical characteristics, medical history, admission symptoms, laboratory parameters, and outcomes of the patients were recorded.

RESULTS

This study comprised 307 patients with severe hyponatremia in total. With 39.4% of all tumors being lung cancer (n = 121), nausea and vomiting were the most common admission symptoms for patients with severe hyponatremia. The 30-day mortality rate of profound hyponatremia cancer patients in the emergency department was 13.4%. The albumin level (p < 0.001), the hemoglobin level (p = 0.033), the TNM stage (p = 0.004), the Eastern Cooperative Oncology Group Performance Status (ECOG-PS) score (p < 0.001), hypocalcemia (p = 0.006), renal insufficiency (p = 0.035), and the efficacy of sodium supplementation (p = 0.006) were significantly associated with 30-day mortality. Binary logistic regression analysis showed that a lower albumin level (OR 0.924, 95% CI 0.861-0.991, p = 0.028) and higher ECOG score (OR 8.443, 95% CI 3.568-19.976, p < 0.001) were independent risk factors for 30-day mortality. The overall survival of emergency cancer patients with severe hyponatremia was also examined. The results of the COX regression analysis demonstrated that the efficacy of sodium supplementation (OR = 2.643, 95% CI 1.593-4.386, p < 0.001), a low albumin level (OR = 0.654, 95% CI 0.463-0.923, p = 0.016), the TNM stage (OR = 4.606, 95% CI 2.846-7.455), and a higher ECOG score (OR = 1.738, 95% CI 1.292-2.338, p < 0.001) were independent risk factors for overall survival.

CONCLUSIONS

The clinical manifestations of severe hyponatremia in emergency cancer patients are varied. Hypoalbuminemia and a higher ECOG score are independent risk factors for 30-day mortality and overall survival. Severe hyponatremia patients with a high ECOG score and/or a low albumin level should be monitored and followed more closely.