Risk-adjusted average cost of postoperative complications stratified by the occurrence of kidney disease. PC indicates postoperative complications; GI, gastrointestinal complications; PC/MV, pulmonary complications and/or mechanical ventilation; CV, cardiovascular complications and/or need for vasopressors; NC, neurological complications and/or delirium; PrC, procedural complications; VTE, venous thromboembolism; SS, severe sepsis; WC mechanical wound complications and/or surgical infections.