Hypokalemia is frequent and has prognostic implications in stable patients attending the emergency department

Background Potassium disturbances are associated with adverse prognosis in patients with chronic conditions. Its prognostic implications in stable patients attending the emergency department (ED) is poorly described. Aims This study aimed to assess the prevalence of dyskalemia, describe its predisposing factors and prognostic associations in a population presenting the ED without unstable medical illness. Methods Post-hoc analysis of a prospective, cross-sectional, multicenter study in the ED of 11 French academic hospitals over a period of 8 weeks. All adults presenting to the ED during this period were included, except instances of self-drug poisoning, inability to complete self-medication questionnaire, presence of an unstable medical illness and decline to participate in the study. All-cause hospitalization or deaths were assessed. Results A total of 1242 patients were included. The mean age was 57.2 +/- 22.3 years, 51% were female. The distribution according to potassium concentrations was: hypokalemia<4mmol/L(n = 620, 49.9%), normokalemia 4-5mmol/L(n = 549, 44.2%) and hyperkalemia >5mmol/L(n = 73, 0,6%). The proportion of patients with a kalemia<3.5mmol/L was 8% (n = 101). Renal insufficiency (OR [95% CI] = 3.56[1.94-6.52], p-value <0.001) and hemoglobin <12g/dl (OR [95% CI] = 2.62[1.50-4.60], p-value = 0.001) were associated with hyperkalemia. Female sex (OR [95% CI] = 1.31[1.03-1.66], p-value = 0.029), age <45years (OR [95% CI] = 1.69 [1.20-2.37], p-value = 0.002) and the use of thiazide diuretics (OR [95% CI] = 2.04 [1.28-3.32], p-value = 0.003), were associated with hypokalemia<4mmol/l. Two patients died in the ED and 629 (52.7%) were hospitalized. Hypokalemia <3.5mmol/L was independently associated with increased odds of hospitalization or death (OR [95% CI] = 1.47 [1.00-2.15], p-value = 0.048). Conclusions Hypokalemia is frequently found in the ED and was associated with worse outcomes in a low-risk ED population.