Postoperative acute kidney injury (AKI) affects approximately 2% to 40% of patients undergoing cardiac and major noncardiac surgeries.~Older patients are more susceptible to renal impairment than younger patients. However, the incidence and associations of AKI in older patients are rarely understood.~Generally, in-depth knowledge of risk factors and thus able to identify patients at high risk to develop postoperative AKI is essential to optimize perioperative prevention and protection strategies.~In this retrospective study, the investigators intend to develop and validate a predictive model for postoperative using the identified risk factors.~The primary outcome is postoperative AKI, which according to the Kidney Disease: Improving Global Outcomes (KDIGO) criterion, is defined as an absolute increase in serum creatinine of 0.3 mg/dL within 48 hours or a 1.5-fold increase from preoperative baseline within 7 days after surgery.
Postoperative acute kidney injury is associated increased risk of morbidity and mortality. Older patients are at high risk of developing postoperative acute kidney injury. However, the incidence and associations of postoperative acute kidney injury in older patients are not well understood. This study aims to develop and validate a predictive nomogram for postoperative acute kidney injury in older patients undergoing noncardiac surgery.