Hypernatremia at admission predicts poor survival in patients with terminal cancer: a retrospective cohort study

BACKGROUND: Although palliative care providers, patients, and their families rely heavily on accurate prognostication, the prognostic value of electrolyte imbalance has received little attention. METHODS: As a retrospective review, we screened inpatients with terminal cancer admitted between January 2017 and May 2019 to a single hospice-palliative care unit. Clinical characteristics and laboratory results were obtained from medical records for multivariable Cox regression analysis of independent prognostic factors. RESULTS: Of the 487 patients who qualified, 15 (3%) were hypernatremic upon admission. The median survival time was 26 days. Parameters associated with shortened survival included male sex, advanced age (> 70 years), lung cancer, poor performance status, elevated inflammatory markers, azotemia, impaired liver function, and hypernatremia. In a multivariable Cox proportional hazards model, male sex (hazard ratio [HR] = 1.53, 95% confidence interval [CI]: 1.15–2.04), poor performance status (HR = 1.45, 95% CI: 1.09–1.94), leukocytosis (HR = 1.98, 95% CI: 1.47–2.66), hypoalbuminemia (HR = 2.06, 95% CI: 1.49–2.73), and hypernatremia (HR = 1.55, 95% CI: 1.18–2.03) emerged as significant predictors of poor prognosis. CONCLUSION: Hypernatremia may be a useful gauge of prognosis in patients with terminal cancer. Further large-scale prospective studies are needed to corroborate this finding.