Table 4.

Univariable logistic regression analysis: overall hospital acquired infection

		OR	95% CI	P-value
Admission year	2019	Ref
	2020	1.08	0.88–1.33	0.434
Age category	40	Ref
	40–59	1.51	1.10–2.08	0.011
	≥ 60	2.74	2.07–3.63	< 0.001
Sex	Male	Ref
	Female	1.26	1.02–1.55	0.033
ASA score	Low (1–2)	Ref
	High (3–5)	3.61	2.79–4.67	< 0.001
	Not recorded	2.80	2.07–3.78	< 0.001
CCI	0	Ref
	1	2.17	1.60–2.96	< 0.001
	≥ 2	2.91	2.33–3.63	< 0.001
Admission type	Elective	Ref
	Emergency	1.86	1.51–2.28	< 0.001
Anaesthetic type	Regional/sedation	Ref
	General anaesthetic	2.37	1.32–4.26	0.004
	Not recorded	3.42	1.81–6.46	< 0.001
Length of index procedure (hours)	≤ 1	Ref
	1–4	3.28	2.49–4.32	< 0.001
	> 4	7.12	5.10–9.96	< 0.001
	Not recorded	7.13	4.81–10.56	<  0.001
ICU/CCU Admission	No	Ref
	Yes	7.28	5.84–9.06	<  0.001
No. of separate theatre visits	1	Ref
	2	3.57	2.66–4.78	<  0.001
	> 2	9.27	6.58–13.08	<  0.001
Length of stay	Day case	Ref
	Overnight	1.28	0.60–2.74	0.528
	> 2 days	12.94	7.07–23.65	<  0.001
Specialty unit	Plastic surgery	Ref
	Breast & Endocrine	1.16	0.49–2.73	0.730
	Cardiothoracics	6.54	3.98–10.76	<  0.001
	Colorectal	2.98	1.60–5.54	0.001
	Head & Neck & Plastics	17.19	8.04–36.72	<  0.001
	Emergency General Surgery	1.93	1.12–3.31	0.017
	Head, Neck & Otolaryngology	1.03	0.44–2.43	0.941
	Hepatobiliary & Upper Gastrointestinal	2.68	1.31–5.47	0.007
	Nephrology Surgical	2.49	1.38–4.47	0.002
	Neurosurgery	2.45	1.48–4.05	0.001
	Oral & Maxillofacial	0.67	0.20–2.25	0.517
	Orthopaedic	3.44	2.18–5.41	<  0.001
	Thoracics	2.42	1.13–5.17	0.022
	Urology	1.49	0.82–2.70	0.193
	Vascular	3.85	2.18–6.80	<  0.001
No. of admission episodes per patient	1	Ref
	> 1	1.98	1.51–2.59	<  0.001

OR: odds ratio, 95% CI: 95% Confidence interval, ASA score: American society of anesthesiology physical classification status score, CCI = Charlson comorbidity index, ICU: intensive care unit, CCU: coronary care unit, Ref: Referent