Table 3.

Associations between initial antibiotic regimen, selected covariates¹ and the composite outcome clinical failure

Characteristic	N	Risk of failure within stratum	P-value2	OR3	95% CI
Initial antibiotic regimen
Inappropriate	10	35.7%	0.004	3.4	1.3, 9.1
Appropriate	20	13.6%		Ref.
Age, years
<65	12	10.6%	0.002	Ref.
>65	18	29.0%		2.3	0.90, 5.7
Department of admission
Surgical	23	15.5%
Nonsurgical	7	25.9%	0.19
Operation delay
Within 1 day	26	16.6%
After more than 1 day	4	21.0%	0.63
Origin of infection
Upper gastrointestinal tract	9	23.1%	0.003	0.77	0.28, 2.1
Appendix	6	6.9%		0.27	0.09, 0.84
Lower gastrointestinal tract	14	29.8%		Ref.
Other	1	50.0%		NA
Total	30	17.1%

¹Comorbidity, CDS and treatment with antibiotics in the 30 days prior to hospitalization were also analysed, but no association with clinical failure was found.

²Pearson's χ².

³Odds ratio following multivariate logistic regression with age, origin of infection, and initial antibiotic regimen.