MO382POTASSIUM DISTURBANCES AND CHARACTERISTICS OF RENAL RECOVERY IN 1519 CONSECUTIVE PATIENTS WITH ACUTE KIDNEY INJURY
Authors: Montgomerie Christina , Spaak Jonas , Evans Marie , Jacobson Stefan H 
Published: May 2021

Abstract

Background and Aims
Acute kidney injury (AKI) is a common condition occurring in about 15% of hospitalized patients, often complicated by hyperkalemia causing increased risk for adverse cardiovascular events. The level of AKI (prerenal, renal or postrenal), is of importance as both pathophysiology and prognosis differ. Although early recovery from AKI is associated with less morbidity and mortality, patients with a history of AKI have a higher long-term risk of end-stage kidney disease and death. Most AKI studies include critically ill patients treated at intensive care units; less is known about AKI patients in general. The aim of this large single-center study was to report potassium disturbances and short-term hospital outcomes in 1519 consecutive patients with AKI admitted to a nephrology department.

Methods
All patients diagnosed with AKI between 2009 and 2018 and admitted to the nephrology department at Danderyd University Hospital, Stockholm, Sweden, were screened. Patients who fulfilled the KDIGO 2012 definition of AKI, a sCreatinine (sCr) &gt;1.5 times baseline or increase by &gt;0.3 mg/dL (&gt;26.5 mmol/L), were included. Potassium levels at admission were classified into hypokalemia (&lt;3.5 mmol/L), normokalemia (3.5-4.9 mmol/L), mild hyperkalemia (5-5.4 mmol/L), moderate (5.5-5.9 mmol/L) and severe hyperkalemia (≥6 mmol/L). Partial recovery was defined as an in-hospital sCr decrease by at least 30% while modest recovery was defined as s sCr decrease by at least 50%. Using logistic regression with conditional backward selection, we determined which variables that were associated with a partial recovery or a hyperkalemia (&gt;5 mmol/L). Patients on dialysis treatment were excluded. Patients were followed until either discharge or death, whichever came first.

Results
In 1519 patients with AKI, the majority (n=687 (45%)) had prerenal AKI, followed by AKI on chronic (defined as chronic kidney disease combined with any type of AKI) (n=536 (35%)), renal (n=166 (11%)) and postrenal AKI (n=130 (9%)). At admission, 30% of patients had any hyperkalemia, whereas 7% had severe hyperkalemia. Normokalemia was seen in 60% of the patients while 10.5% had hypokalemia. The more hyperkalemia, the higher level of sCr at admission, the more acidosis and the less proteinuria. Proteinuria was most pronounced in patients with mild hyperkalemia and normokalemia. In-hospital partial renal recovery was seen in 63% of the patients, while 38% had a modest recovery. Mortality during hospitalization was 4%; most of these patients had normokalemia (58%), followed by mild (18%) and moderate hyperkalemia (15%). In the prerenal and postrenal groups, most patients had a partial renal recovery (76% and 73% respectively). In patients with renal and AKI on chronic the proportions were lower (40% and 51%, respectively).

Conclusion
This study provides data from a large, contemporary AKI patient cohort under nephrology care. Severe potassium disturbances are common and short-term outcomes differ substantially in patients of variable AKI level and etiology. These findings have important implications for prognostic evaluation upon admission and further resource planning.