Table 3.

Incidence rate ratios of multivariable analysis with backward stepwise selection using Poisson regression

Variable		IRRa (95% CIb)	P
ASAc Class		Ref	.
1		Ref	.
2		0.45 (0.11, 1.88)	0.275
3		0.86 (0.24, 3.08)	0.811
4		1.13 (0.30, 4.27)	0.853
5		3.13 (0.78, 12.59)	0.108
Age		1.05 (1.02, 1.08)	<0.001
logMorbidity P-POSSUM		0.28 (0.13, 0.61)	0.001
logMortality P-POSSUM		1.58 (1.16, 2.15)	0.004
PRBd Transfusion		1.66 (1.13, 2.42)	0.009
Cancer		1.57 (1.01, 2.44)	0.044
Systolic blood pressure		0.99 (0.98, 1.00)	0.053
Surgery indication
Ileus/obstruction		Ref	.
Perforation		1.17 (0.69, 2.00)	0.555
Ischaemia		1.94 (1.05, 3.57)	0.034
Infection		N/A	N/A
Bleeding		2.19 (0.94, 5.09)	0.070
Other		1.31 (0.48, 3.59)	0.603
Surgical procedure
Resection		Ref	.
Adhesiolysis		0.50 (0.24, 1.03)	0.061
Stoma formation		0.98 (0.63, 1.51)	0.908
Other		0.42 (0.21, 0.83)	0.013
Bowel repair		0.82 (0.38, 1.73)	0.594
Vascular		0.40 (0.12, 1.29)	0.126

^aIRR: incidence rate ratio;

^bCI: confidence interval;

^cASA: American Society of Anaesthesiologists;

^dPRB: Packed Red Blood.