Table 3 The results of subgroup analyses based on the surgical procedure and scope of gastrectomy

Lung infection

RR = 0.51,

95%CI[0.18; 1.40]

RR = 0.35,

95%CI[0.04; 3.22]

RR = 0.62,

95%CI[0.33; 1.15]

RR = 0.72,

95%CI[0.19; 2.81]

RR = 0.54,

95%CI[0.29; 1.01]

RR = 0.54,

95%CI[0.15; 1.95]

Urinary tract infection

RR = 0.33,

95%[0.01; 8.02]

RR = 0.98,

95%CI[0.14; 6.63]

RR = 0.58,

95%CI[0.29; 1.19]

RR = 2.14,

95%CI[0.20; 23.49]

RR = 0.5,

95%CI[0.21; 1.21]

RR = 0.60,

95%CI[0.20; 1.80]

Surgical site infection

RR = 0.51,

95%CI[0.10; 2.74]

RR = 0.95,

95%CI[0.06; 14.22]

RR = 0.94,

95%CI[0.45; 1.96]

RR = 0.84,

95%CI[0.36; 1.95]

RR = 0.77,

95%CI[0.18; 3.37]

RR = 0.97,

95%CI[0.25; 3.75]

Postoperative anastomotic leakage

RR = 0.34,

95%CI[0.04; 3.25]

RR = 1.05,

95%CI[0.07; 16.17]

RR = 1.21,

95%CI[0.53; 2.74]

RR = 2.56,

95%CI[0.39; 16.93]

RR = 1.15,

95%CI[0.42; 3.10]

RR = 0.97,

95%CI[0.23; 4.18]

Postoperative ileus

RR = 0.34,

95%CI[0.04; 3.25]

RR = 1.05,

95%CI[0.07; 16.17]

RR = 1.95,

95%CI[0.95; 4.02]

RR = 0.69,

95%CI[0.12; 4.01]

RR = 2.13,

95%CI[0.95; 4.81]

RR = 1.00,

95%CI[0.23; 4.29]

Postoperative length of stay

MD = -1.79,

95%CI[−2.59; −0.99]

MD = -1.64,

95%CI[−2.60; −0.33]

MD = -1.88,

95%CI[−2.63;-1.12]

MD = -1.95,

95%CI[−2.99; −0.91]

MD = -1.83,

95%CI[−3.01; −0.66]

MD-1.36,

95%CI[−1.70; −1.03]

Flatus

MD = -0.75,

95%CI[−1.09; − 0.41]

MD = -0.45,

95%CI[− 0.62; − 0.28]

MD = -0.83,

95%CI[−1.22;-0.45]

MD = -0.81,

95%CI[− 2.04; 0.43]

MD = -0.68,

95%CI[− 1.08; − 0.27]

MD = -0.59,

95%CI[− 0.83; − 0.35]

Defecation

MD = -1.63,

95%CI[− 2.79; − 0.47]

Not applicable

MD = -0.54,

95%CI[− 0.86; − 0.22],

MD = -1.36,

95%CI[− 3.05; 0.34]

MD = -1.05,

95%CI[− 1.45; − 0.65]

MD = -0.65,

95%CI[− 1.28; − 0.02]

Readmission rates

RR = 1.02,

95%CI[0.02; 50.41]

RR = 3.00,

95%CI[0.13; 69.79]

RR = 1.99,

95%CI[1.04; 3.82]

RR = 1.13,

95%CI[0.32; 4.08]

RR = 2.64,

95%CI[1.20; 5.81]

RR = 0.95,

95%Ci[0.06; 14.82]