Summary of meta-analyses
Risk factor | Blood transfusion | Tumour | Obesity | Diabetes | Tobacco use | |
Case number | RF+SSI+ | 39 | 226 | 720 | 229 | 340 |
RF+SSI− | 998 | 3924 | 28 717 | 5330 | 13 645 | |
RF− SSI+ | 1075 | 769 | 531 | 1314 | 938 | |
RF− SSI− | 62 830 | 44 733 | 36 398 | 62 893 | 54 500 | |
Meta-analysis | LogOR | 0.94 | 0.8 | 0.58 | 0.53 | 0.36 |
OR | 2.55 | 2.23 | 1.79 | 1.7 | 1.43 | |
SE | 0.17 | 0.09 | 0.12 | 0.15 | 0.07 | |
z | 5.57 | 8.8 | 5.07 | 3.5 | 5.54 | |
P value | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | |
Heterogeneity test | I2 | 0.00% | 0.00% | 67.56% | 64.07% | 0.00% |
Q (df) | 0.17 (3) | 1.34 (4) | 11.58 (4) | 21.13 (7) | 5.78 (5) | |
P value | 0.983 | 0.85 | 0.02 | <0.001 | 0.33 | |
Leave-one-out sensitivity | lowest LogOR | 0.88 | 0.7 | 0.54 | 0.44 | 0.32 |
Highest LogOR | 0.96 | 0.86 | 0.66 | 0.64 | 0.43 | |
Egger’s publication bias | β | 0.09 | 0.05 | 1.79 | −1.21 | 0.76 |
SE | 1.08 | 0.81 | 7.6 | 0.89 | 0.73 | |
z | 0.08 | 0.06 | 1.12 | −1.35 | 0.91 | |
P value | 0.934 | 0.95 | 0.263 | 0.178 | 0.363 |
The presenting data of the tumour were after exclusions of outliers.
I² refers, Heterogeneity index; RF+, exposure to the risk factor; RF−, no exposure to the risk factor; SSI, surgical site infections; SSI+, SSI positive; SSI−, SSI negative.