Antibiotic Prophylaxis | Control group | P values | Absolute risk reduction | 95% CI | Relative risk reduction (%) | NNTB (95% CI) | |

Analysis by ITT: assuming all the participants violating protocol or lost to follow-up would have developed SSI | |||||||

n=77 | n=77 | ||||||

No of SSI | n=1 | n=8 | |||||

Incidence rate of SSI | 1.3% | 10.4% | P=0.034* | 9.1% | 1.8 to 16.4 | 87.5 | 11.0 (6.1 to 55.6) |

Analysis by ITT: assuming none of the participants violating protocol or lost to follow-up would have developed SSI | |||||||

n=77 | n=77 | ||||||

No of SSI | n=5 | n=16 | |||||

Incidence rate of SSI | 6.5% | 20.8% | P=0.017* | 14.3% | 3.7 to 24.9 | 68.8 | 7.0 (4.0 to 27.0) |

*P values are results of Fisher’s exact test.

ITT, intention-to-treat; NNTB, number needed to treat for benefit; NNTH, number needed to treat for harm; SSI, surgical site infection.