Definitions
The date of hospital admission was accepted as the first day. Patients
using antihypertensive drugs were accepted as hypertensive, while those
using antidiabetic drugs were accepted as diabetic.
The estimated glomerular filtration rate (eGFR) was calculated using the
Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula
[14]. Decreased eGFR was defined as < 60 mL/min/1.73
m2.
AKI on admission or during hospital stay was defined according to Kidney
Disease: Improving Global Outcomes (KDIGO) criteria as follows: stage 1,
as an increase in SCr level by 0.3 mg/dL within 48 hours or 1.5 to 1.9
times increase in SCr from baseline within 7 days; stage 2, as 2 to 2.9
times increase in SCr within 7 days; stage 3, as 3 or more times
increase in SCr within 7 days or initiation of renal replacement therapy
(RRT) [15]. Patients were stratified according to the highest AKI
stage attained during their hospital stay. Available baseline value for
each patient was taken as the mean outpatient value 7-365 days prior to
admission [16]. If baseline value of SCr was not available, the
lowest value during hospitalisation was taken [15]. We did not use
the urine output criteria to define AKI as the documentation of urine
output in the electronic health record was unavailable.
Renal glycosuria was defined in a person if blood glucose level rises
higher than 170–200 mg/dL who doesn’t have diabetes or if blood glucose
level rises higher than 200–250 mg/dL who has type 2 diabetes mellitus
and the filtered glucose load exceeds the capacity for tubular glucose
reabsorption [17]
Proteinuria was defined as the presence of ⩾1+ on dipstick urinalysis.
Trace proteinuria was considered as negative. Microscopic hematuria was
accepted as the presence of three or more erythrocytes per high-power
field. Pyuria was also accepted as the presence of five or more
leukocytes per high-power field.
The follow-up period started from the date of hospitalization and ended
the day of discharge or in-hospital mortality.