Twenty-eight RCTs (N=9,478) were included.
It was not possible to analyse the combined data relating to post-operative fever, pneumonia and septicaemia, due to inconsistent information. In addition, there was a lack of clear differentiation between sepsis and fever due to other causes.
Single versus multiple-dose prophylaxis: the OR was 1.06 (95% CI: 0.89, 1.25) when using the fixed-effect model, and 1.04 (95% CI: 0.86, 1.27) when using hte random-effects model. Zelen's test for homogeneity (P) was 0.091, indicating some evidence of heterogeneity.
The following results were all obtained using a random-effects model in a post-hoc analysis.
Beta-lactam (21 RCTs): the OR was 1.10 (95% CI: 0.90, 1.33).
Non-beta-lactam (7 RCTs): the OR was 0.65 (95% CI: 0.34, 1.23; P=0.13).
Obstetric or gynaecological (10 RCTs, N=1,480: the OR was 1.14 (95% CI: 0.62, 2.09).
Non obstetric or gynaecological (19 RCTs): the OR was 1.03 (95% CI: 0.82, 1.28; P=0.75).
Post-operative wound assessment blinded (15 RCTs): the OR was 1.24 (95% CI: 0.95, 1.63).
Post-operative wound assessment non-blinded (13 RCTs): the OR was 0.91 (95% CI: 0.71, 1.17; P=0.10).
Multiple dose regimes of greater than 24 hours (16 RCTs): the OR was 1.03 (95% CI: 0.77, 1.36).
Multiple dose regimes of less than 24 hours (12 RCTs): the OR was 1.03 (95% CI: 0.76, 1.40; P=0.95).
Overall rate of infection in each study: the expected OR (random effects) for the single- vs multiple-dose comparison increased by a factor of 1.12 (95% CI: 0.89, 1.42; P=0.33) for each increment of 5% on the overall infection rate.