ALB and infection: In superficial SSI subgroup, the infection rate was 1.64 % (45/2745) in the albumin <3.5 g/dL group and 0.67 % (392/58,721) in the albumin >3.5 g/dL group, (RR = 2.46, 95 % CI [1.81 3.35], Z = 5.73, p < 0.00001 in a fixed model (I2 = 0 %).