An increasing trend of the incidence of complications was seen with an increase in the severity of malnutrition, whereas when the Mann-Whitney test was applied, absolute lymphocyte count <2300, serum albumin <3.5, Hb <11, ASA score>2, packed cell volume (PCV) <32, and age >53 correlated with postoperative complications. Here, GSTM1 is linked to malnutrition.