The factors significantly associated with the occurrence of SSI were age (> 47.5 years), male gender, preoperative hemoglobin concentration (< 11 g/dL), preoperative albumin concentration (< 4.1 g/dL), preoperative blood glucose concentration (> 124 mg/dL), colorectal surgery, intestinal obstruction, ASA score greater than 2, NNIS risk index greater than 0, laparoscopic surgery, wound irrigation (povidone iodine solution), and operation time (> 120 min). Here, ALB is linked to intestinal obstruction.