In selecting the matching variables, general information about the patients (age, sex, weight), as well as preoperative albumin, ASA classification, duration of surgery, intraoperative fluid volume, and prevalence of hypertension and diabetes mellitus, which have a potential impact on postoperative pneumonia, were included in the equations in order to reduce the impact of these factors on the outcome. The gene discussed is ALB; the disease is susceptibility to pneumonia measurement.