One in five patients develop Post-operative Acute Kidney Injury after Major Surgery

EPIS-AKI trial which is a comprehensive, multinational study, reported that post-operative acute kidney injury (PO-AKI) occurs in nearly one out of five patients who underwent urologic, cardiac, and vascular surgery. The main risk factors for the occurrence of PO-AKI were the intraoperative use of vasopressors and the use of aminoglycosides. PO-AKI resulted in adverse outcomes like increased mortality and hospital stay. 

The trial results were published in the journal - Intensive Care Medicine on 28 July 2023. 

Major surgeries have the risk of associated post-operative acute kidney injury. Abdominal and cardiac surgeries have an increased incidence of PO-AKI. As there is uncertainty on the incidence and the outcomes of PO-AKI, researchers conducted a prospective, observational, multicenter, cohort study in 30 countries in patients undergoing major surgery. 

Patients aged 18 years and above and undergoing major surgery that lasted more than 2 hours with the need for subsequent intensive care unit (ICU) or high dependency unit admission were recruited in the study. The primary endpoint was the occurrence of PO-AKI within 72 h of surgery defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included PO-AKI severity and duration, use of renal replacement therapy (RRT), mortality, and ICU and hospital length of stay.  For statistical analysis, fisher's exact test and Pearson’s Chi-squared test were used to compare categorical variables between groups.

Key findings: 

• About 10,568 patients were examined, and 1945 (18.4%) developed PO-AKI.
• Nearly 1236 (63.5%) were in KDIGO Stage 1, 500 (25.7%) were in KDIGO Stage 2, and 209 (10.7%) were in KDIGO Stage 3.
• In 33.8% of patients, PO-AKI was persistent, and 170/1945 (8.7%) of patients with PO-AKI received RRT in the ICU.
• Patients with PO-AKI had greater ICU and hospital mortality and longer length of stay.
• Risk factors for PO-AKI included older age, comorbidities (hypertension, diabetes, chronic kidney disease), type, duration, and urgency of surgery as well as intraoperative vasopressors, and aminoglycosides administration.

Thus, this first prospective international observational trial conducted across multiple geographic settings and country-based income levels provided important data on the occurrence rate, morbidity, and mortality of PO-AKI. 

Further reading: Zarbock, A., Weiss, R., Albert, F. et al. Epidemiology of surgery-associated acute kidney injury (EPIS-AKI): a prospective international observational multi-center clinical study. Intensive Care Med (2023). https://doi.org/10.1007/s00134-023-07169-7