Dysnatremias in emergency patients with acute kidney injury: A cross-sectional analysis.

PURPOSE: We aimed to investigate the prevalence, risk factors and outcome of hypo- and hypernatremia in emergency patients with acute kidney injury (AKI).

METHODS: In this cross-sectional analysis all emergency patients between January 1st 2017 and December 31st 2018 with measurements of creatinine and sodium were included. Baseline characteristics, medication and laboratory data were gathered. Chart reviews were performed to identify patients with a diagnosis of chronic kidney disease (CKD) and to extract baseline creatinine. For all other patients the ADQI backformula was used to calculate baseline creatinine. AKI was graduated using creatinine criteria of the acute kidney injury network. Binary logistic regression analysis was used to identify risk factors for appearance of dysnatremias and outcome.

RESULTS: AKI was found in 8% of patients. 392 patients (23.16%) had hyponatremia, 24 (1.4%) had hypernatremia. Use of potassium sparing diuretics, a medical cause for emergency referral, use of thiazide diuretics and AKI stage were the strongest risk factors for hyponatremia. Loop diuretics, a medical cause for emergency referral and AKI stage were risk factors for hypernatremia. In patients with all classes of hyponatremia, length of hospital stay was significantly longer compared to patients with a normal serum sodium. In the binary logistic regression analysis with death as outcome, hyponatremia as well as severe hypernatremia were independent risk factors for mortality.

CONCLUSIONS: Dysnatremias are common in emergency patients with AKI. Diuretic medication is a major risk factor for hypo- and hypernatremia. Both hyponatremia and severe hypernatremia were independent risk factors for adverse outcome.