Table 3.

Cox Proportional Hazards Model of BUTI by Antibiotic.

Antibiotic	Hazard ratio	95% Confidence interval	p
Amoxicillin	reference	-	-
Cephalexin	1.26	0.64–2.51	0.50
Nitrofurantoin	0.52	0.05–5.63	0.59
Trimethoprim-sulfamethoxazole	0.86	0.41–1.81	0.69
Sex
Female	reference	-	-
Male	1.57	0.77–3.21	0.22
Gestational age, weeks
≤25	reference	-	-
26–28	1.77	0.92–3.40	0.09
29–32	3.02	1.06–8.58	0.04
33–36	1.69	0.36–7.93	0.50
≥37	1.02	0.15–6.83	0.98
Race/ethnicity
White	reference	-	-
Black	2.14	1.15–3.98	0.02
Hispanic	1.56	0.77–3.20	0.22
Other	2.49	0.86–6.83	0.09
Birth weight, g
<1000	reference	-	-
1000–1499	0.47	0.21–1.05	0.07
1500–2499	1.26	0.42–3.19	0.68
2500–3499	2.11	0.39–11.31	0.38
≥3500	3.71	0.55–25.81	0.19
Admission type
Inborn	reference	-	-
Outborn	1.37	0.75–2.87	0.26
Postnatal age, days
0–30	reference	-	-
30–60	1.12	0.37–3.39	0.84
>60	1.41	0.48–4.15	0.53

BUTI: breakthrough urinary tract infection.