Prevalence and impact on outcome of sodium and potassium disorders in patients with community-acquired pneumonia: A retrospective analysis

Abstract

Introduction: Disorders of sodium and potassium are common and predictors of adverse outcome. Prevalence and impact on outcome of hypokalemia, hyperkalemia, hyponatremia and hypernatremia were investigated in emergency patients with community-acquired pneumonia (CAP). Methods: Patients ≥18 years presenting to our emergency department between January 1st 2017 and December 31st 2018 with on-admission electrolyte measurements were included. Chart reviews were performed to identify patients with CAP. Results: 19.948 cases had measurements of sodium and potassium of which 469 had CAP (2.4%). Prevalence of hypo- and hypernatremia was significantly increased in patients with compared to those without CAP (hyponatremia: 28.8% vs. 10.5% respectively, p<0.0001; hypernatremia: 1.9% vs. 0.6% respectively, p=0.002). The prevalence of hypo- and hyperkalemia was significantly higher in patients with than without CAP (hypokalemia 15.6% vs. 11.4% respectively, p=0.004; hyperkalemia: 4.5% vs. 2.0% respectively, p=0.001). Hyponatremia was significantly associated with longer hospital stay in patients with CAP (regression coefficient 0.194, standard error 0.079, p=0.015). None of the investigated electrolyte disorders were predictive of 30-day re-admission and 180-day pneumonia recurrence rates. Use of loop diuretics was an independent predictor for 30-day re-admission (OR 2.351 (1.099-5.03). p=0.028). Pneumonia Severity Index (PSI) risk class was an independent predictor of 180-day pneumonia recurrence (OR 1.494 (1.022-2.184), p=0.038). Conclusion: Dysnatremias and dyskalemias are common findings complicating CAP in emergency patients. Prevalence of hyponatremia was highest followed by hypokalemia. Hyponatremia was an independent predictor of prolonged length of hospital stay. Loop diuretic use was associated with 30-day readmission and PSI risk class with 180-day pneumonia recurrence.