Table 4.

Univariable and multivariable Poisson regression of factors related to mortality

	Univariable analysis		Multivariable analysis
	Relative risk	P	Relative risk	P
In‐hospital surgical delay	1·88 (1·28, 2·77)	0·001	1·68 (1·01, 2·78)	0·045
Age category (years)
0–10	0·22 (0·03, 1·57)	0·131	0·00 (0·00, 0·00)	< 0·001
11–20	1·20 (0·64, 2·25)	0·577	1·01 (0·40, 2·50)	0·991
21–40	1·00 (reference)		1·00 (reference)
41–60	1·68 (1·04, 2·73)	0·035	1·57 (0·85, 2·88)	0·151
> 60	2·37 (1·41, 3·99)	0·001	1·50 (0·71, 3·18)	0·293
Female sex	1·05 (0·65, 1·82)	0·836	0·68 (0·34, 1·38)	0·287
Pre‐hospital delay in presentation
< 24 h	1·00 (reference)		1·00 (reference)
24–48 h	1·15 (0·46, 2·86)	0·770	0·35 (0·08, 1·62)	0·180
49–72 h	1·43 (0·62, 3·33)	0·403	0·72 (0·25, 2·08)	0·548
> 3 days	2·13 (1·09, 4·17)	0·027	1·18 (0·54, 2·60)	0·681
Shock	1·43 (0·87, 2·34)	0·159	1·28 (0·71, 2·33)	0·416
Initial respiratory rate
Normal	1·00 (reference)		1·00 (reference)
Tachypnoea	0·70 (0·43, 1·13)	0·143	0·66 (0·40, 1·07)	0·090
Admission diagnosis
Acute abdomen/peritonitis	6·54 (2·83, 15·10)	< 0·001	4·49 (1·69, 11·95)	0·003
Acute appendicitis	1·28 (0·37, 4·45)	0·695	1·35 (0·34, 5·42)	0·673
Bowel or gastric perforation	7·65 (3·23, 18·10)	< 0·001	3·73 (1·25, 11·08)	0·018
Volvulus	3·70 (1·47, 9·32)	0·005	2·64 (0·84, 8·26)	0·097
Hernia, irreducible	1·00 (reference)		1·00 (reference)
Other	0·00 (0·0, 0·00)	< 0·001	0·00 (0·00, 0·00)	< 0·001
Any co‐morbidity	0·89 (0·48, 1·66)	0·709	0·74 (0·27, 2·02)	0·552

Values in parentheses are 95 per cent confidence intervals.