11. tbl. 99.árg. 2013
Epidemiology of acute kidney injury in a tertiary care university hospital according to the RIFLE criteria
Bráður nýrnaskaði á Landspítala 2008-2011 og áhættuþættir og afdrif sjúklinga með alvarlegan skaða
Introduction: Acute kidney injury (AKI) is a common problem in hospitalized patients, requiring extensive treatment and carries a high mortality rate. This study was designed to assess the epidemiology of AKI, and risk factors and outcome of patients with severe AKI in a tertiary care university hospital in Iceland.
Material and methods: All adult patients with measured serum creatinine (SCr) in Landspitali University Hospital from January 2008 to December 2011, who had a measured baseline SCr in the preceeding six months, were included. Patients were categorized according to the RIFLE-criteria into risk (stage 1), injury (stage 2) and failure (stage 3) groups based on their highest SCr, using the lowest SCr in the previous six months as baseline.
Results: A total of 17,693 individuals (out of 74,960) had a baseline SCr and their data were used for analysis. AKI occured in 3,686 (21%) with 12%, 5% and 4% of stage 1, 2 and 3, respectively. There were more females in stage 1 and stage 2 and more males in stage 3 (p< 0.001). Contributing causes for AKI in patients with stage 3 AKI were surgery (22%), circulatory shock (23%), sepsis (14%), cardiovascular insult (32%), respiratory failure (27%), bleeding (10%), trauma (7%) and AKI associated drugs (61%). Dialysis was required in 11% and in 0.7% for longer than 30 days but none > 90 days. One year survival was 52%.
Conclusions: Acute kidney injury is common in Iceland and the prognosis of those with severe AKI is dismal. Majority of those patients were taking drugs that increase risk of AKI, providing a target for preventive measures.
Figures and tables:
Figure 1 - Flowchart showing the number of patients with creatinine measurements, how many had a measured baseline and their distribution into stage 1 (risk), stage 2 (injury) and stage 3 (failure) groups. AKI: Acute kidney injury. LUH: Landspitali – The National University Hospital of Iceland.
Figure 2 - Kaplan-Meier plot demonstrating the survival of patients with acute kidney injury in the stage 3 (failure) group of the RIFLE classification. One year survival was 52%.
Table I. RIFLE classification criteria for acute kidney injury. | ||
Category | Criteria | |
R | Stage 1 | Baseline x 1,5 or UO <0.5mL/kg/hour for 6 hours |
I | Stage 2 | Baseline x 2 or UO <0.5mL/kg/hour for 12 hours |
F | Stage 3 | Baseline x 3 or UO <0.3mL/kg/hour for 24 hours |
L | Renal replacement therapy> 4 weeks | |
E | Renal replacement therapy> 90 days |
The RIFLE classification is based on three categories and two outcomes. R=risk (stage 1), I=injury (stage 2), F=failure (stage 3), L=loss, E=end stage. Baseline refers to baseline creatinine value, UO= urinary output
Table II. Patient data. | |||||
Non-AKI |
Risk Stage 1 |
Injury Stage 2 |
Failure Stage 3 |
||
Number (%) | 14.017 (79.2) | 2.077 (11.7) | 840 (4.7) | 769 (4.3) | |
Age (years) | 56.6±19.5 | 67.2±18.3 | 70.3±15.0 | 69.2±15.5 | |
Female (%) | 54.6 | 54.3 | 53.1 | 41.5 | |
AKI= Acute kidney injury. Age is median± standard deviation.
Table III. Comparison of admitted patients and outpatients with stage 3 acute kidney injury | |||
Admitted (n=613) | Outpatients (n=80) | p-value | |
Age (years) | 69.3±15.4 | 65.8±16.4 | <0.001* |
Female (%) | 41.6 | 42.5 | 0.953 |
Baseline creatinine (mmól/L) | 84 (20-1787) | 188 (25-943) | 0.002* |
Hypertension | 199 (32.5%) | 31 (38.8%) | 0.261 |
Ischemic heart disease | 203 (33.1%) | 19 (23.8%) | 0.091 |
Chronic kidney disease | 119 (19.4%) | 29 (36.3%) | 0.001* |
Diabetes | 105 (17.1%) | 12 (15.0%) | 0.633 |
COPD | 83 (13.5%) | 7 (8.8%) | 0.231 |
Chronic liver failure | 16 (2.6%) | 3 (3.8%) | 0.557 |
COPD= Chronic obstructive pulmonary disease, Diabetes= diabetes mellitus type I and II. Age is median ± standard deviation. Baseline refers to median (range) baseline serum creatinine value. *Statistically significant.
Table IV. Causes and risk factors of acute kidney injury in patients with stage 3 (n=693). | ||
Risk factor | n | (%) |
Surgery | 150 | (22) |
Shock | 162 | (23) |
Sepsis | 99 | (14) |
Cardiovascular insult | 222 | (32) |
Bleeding | 72 | (10) |
Respiratory failure | 188 | (27) |
Trauma | 48 | (7) |
Medication | 424 | (61) |
· NSAID | 292 | (42) |
· Contrast | 15 | (2) |
· ACEi/ARB | 204 | (29) |
· Narcotics | 13 | (2) |
· Overdose | 18 | (3) |
The frequency of use of medications that increase the risk of acute kidney injury. NSAID = non-steroidal anti-inflammatory drug, ACEi= angiotensin-converting-enzyme inhibitor,ARB=angiotensin receptor blocker.
Key words: Acute kidney injury, survival, RIFLE criteria, risk factors, comorbid diseases.
Correspondence: Gísli H. Sigurðsson, gislihs@landspitali.is
Long ThE1, Sigurdsson MI2, Indridason OS3, Sigvaldason K2, Sigurdsson GH1,2
1Faculty of Medicine, University of Iceland, 2Department of Anesthesia and Intensive Care, 3Division of Nephrology, Landspítali - The National University Hospital of Iceland, Reykjavík.