Summary of findings 3. Summary of findings: serious adverse events.

Prophylactic antibiotics compared with placebo for COPD
Patients or population: adults with COPD Settings: hospital clinics, multi‐centre Intervention: macrolide, tetracycline, or quinolone Comparison: placebo
Treatment	Anticipated absolute effects (95% CrI)*		Relative effect OR (95% CrI)	No. of participants (studies)
	Absolute probability of an SAE: median (95% CrI)	Risk difference with treatment*
Macrolide (weighted mean 49 weeks' duration)	0.21 (0.18 to 0.25)	49.07 fewer per 1000 (81.18 fewer to 14.23 fewer)	0.76 (0.62 to 0.93)	971 (8)
Quinolone (48 weeks' duration)	0.26 (0.20 to 0.32)	1.873 fewer per 1000 (57.88 fewer to 60.89 more)	1.00 (0.72 to 1.34)	569 (1)
Macrolide + tetracycline (12 weeks' duration)	0.25 (0.15 to 0.37)	9.461 fewer per 1000 (1.07 fewer to 108.5 more)	0.97 (0.52 to 1.66)	101 (1)
*The basis for the anticipatedrisk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CrI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CrI). COPD: chronic obstructive pulmonary disease; CrI: credible interval; OR: odds ratio.

*Absolute probability of events in the placebo arm was 0.26; risk of an SAE with placebo was 260 per 1000.