Center-mediated Differences in Postoperative Acute Kidney Injury Rates: A Post Hoc Analysis of the PROTECTION Trial

Area of Science:

• Nephrology
• Cardiology
• Intensive Care Medicine

Background:

• The PROTECTION trial indicated preoperative amino acid (AA) administration protects renal function in adult cardiac surgery patients.
• Significant variations in outcomes were observed across participating centers, prompting further investigation into center effects.

Purpose of the Study:

• To determine if center-specific effects negate the protective impact of AA on preventing cardiac surgery-associated acute kidney injury (CSA-AKI).

Main Methods:

• A post hoc analysis of data from the multicenter PROTECTION trial was conducted.
• Adult cardiac surgery patients were analyzed, comparing outcomes between low-rate and high-rate CSA-AKI centers.
• Preoperative, intraoperative, and perioperative variables were compared between high-rate centers (HR-C) and other centers.

Main Results:

• Patients in HR-C were older and had more comorbidities, including higher rates of heart failure, hypertension, diabetes, and peripheral vascular disease.
• HR-C patients experienced longer aortic cross-clamp times, higher cardiopulmonary bypass temperatures, and received less frequent diuretic or hemofiltration support.
• Despite these differences, preoperative amino acid administration remained independently associated with a reduced risk of CSA-AKI (RR, 0.79) after adjusting for center effects.

Conclusions:

• High-risk centers (HR-C) managed patients with greater severity and different care protocols.
• Amino acid therapy demonstrated an independent association with CSA-AKI prevention, even when accounting for significant center-level variations in patient characteristics and management.