Hyponatremia as an independent prognostic factor in patients with terminal cancer

Hyponatremia is a common and associated with poor clinical outcome in cancer patients. But little is known regarding hyponatremia in terminal cancer patients. The purpose of this study is to investigate the prognostic role of the hyponatremia in terminal cancer patients.

A retrospective observational study was conducted between January 2010 and December 2012 in a tertiary hospital palliative care unit. Medical records were collected from hospitalized patients who were eligible for obtaining serum sodium level. Hyponatremia was defined as serum sodium <136 mEq/L. And we classified patients into three groups; eunatremia (sodium 136-145 mEq/L), mild to moderate hyponatremia (sodium 126-135 mEq/L), and severe hyponatremia (sodium ≤125 mEq/L). Univariate and multivariate Cox regression analyses were performed to determine factors affecting survival time.

Of the 576 patients, hyponatremia was present in 367 individuals (63.7 %). In the univariate analysis, serum CRP, PPS, and sodium ≤125 mEq/L were associated with survival time (HR = 1.22; p < 0.001, HR = 0.69; p < 0.001, HR = 1.91; p < 0.001). In the multivariate analysis, serum CRP, PPS, sodium 126-135 mEq/L, and sodium ≤125 mEq/L were associated with survival time (HR = 1.16; p < 0.001, HR = 0.70; p < 0.001, HR = 1.19; p = 0.048, HR = 1.75; p < 0.001).

Hyponatremia is an independent prognostic factor in terminal cancer patients and careful clinical concern is needed. In the future, large prospective study is warranted in terminal cancer patients.