Rech JS, Yao K, Bachmeyer C, et al. - Given the prognostic value of low plasma sodium concentration in several disorders, researchers here evaluated its value at admission to prognosticate a complication in adult sickle cell disease patients hospitalized for an initially uncomplicated acute painful episode. In this retrospective study, they included 1,218 stays (406 patients) between 2010 and 2015  in a French referral center for sickle cell disease. Hyponatremia (plasma sodium ≤ 135 mmol/L) at admission in the center was associated with the primary endpoint (a composite criterion including acute chest syndrome, intensive care unit transfer, red blood cell transfusion or inpatient death), and with acute chest syndrome and red blood cell transfusion, but not significantly with intensive care unit transfer. Patients with hyponatremia at admission had longer adjusted mean length of stay by 1.1 days. These findings support its value for targeting patients who may benefit from closer monitoring.