The study analyzed data from 12,269 patients and found that risk factors for prolonged LOS included male gender, congestive heart failure, weight loss, Crohn’s disease, low preoperative albumin, sepsis, higher ASA class, open surgery, long surgical times, postoperative pneumonia, and complications such as deep venous thrombosis, urinary tract infections, and surgical site infections. The gene discussed is ALB; the disease is susceptibility to pneumonia measurement.