Hyponatremia—Long-Term Prognostic Factor for Nonfatal Pulmonary Embolism

Over recent years, studies have shown that in patients with left-sided heart failure, arterial hypertension, and acute coronary syndrome, hyponatremia is a negative prognostic factor. In this context, there is raising interest in the association between hyponatremia and pulmonary embolism (PE). This retrospective cohort study includes 404 consecutive patients with confirmed acute nonfatal pulmonary embolism divided into four groups according to their sodium fluctuation pattern. The primary outcome was all-cause mortality and determining the recurrence rate among patients with nonfatal PE using serum sodium levels as a continuous variable. Patients with acquired and persistent hyponatremia had a significantly higher rate of mortality rate than those in the normonatremia group (12.8% and 40.4%, OR- 7.206, CI: 2.383–21.791, p = 0.000 and OR-33.250, CI: 11.521–95.960, p = 0.000 vs. 2%, p < 0.001, respectively). Mean survival time decreases from 23.624 months (95% CI: (23.295–23.953)) in the normonatremia group to 16.426 months (95% CI: (13.17–19.134)) in the persistent hyponatremia group, statistically significant (p = 0.000). The mean survival time for all patients was 22.441 months (95% CI: (21.930–22.951)). The highest recurrence rate was recorded at 12 and 24 months in the acquired hyponatremia group (16.7% and 14.1%, respectively). Serum sodium determination is a simple and cost-effective approach in evaluating the short and long-term prognosis in patients with acute PE.