Independent variables associated with a raised odds of mortality at 1 year post-decision to intervene surgically
Preoperative characteristic		Died n (%) n=59	Alive n (%) n=149	OR (95% CI)	aOR (95% CI)
Small for gestational age at birth	Yes	14 (25%)	16 (11%)	2.6 (10.7 to 6.2) p=0.02	3.6 (1.4 to 9.5) p=0.008
Small for gestational age at birth	No	43 (75%)	128 (89%)	2.6 (10.7 to 6.2) p=0.02	3.6 (1.4 to 9.5) p=0.008
Inotropes required at time of decision for surgical intervention*	Yes	32 (54%)	43 (30%)	2.8 (1.4 to 5.4) p=0.001	2.7 (1.3 to 5.5) p=0.006
	No	27 (466%)	100 (70%)	2.8 (1.4 to 5.4) p=0.001	2.7 (1.3 to 5.5) p=0.006
Non-cardiac congenital anomaly*	Yes	10 (17%)	13 (9%)	2.0 (0.8 to 5.6) p=0.1	6.2 (1.8 to 21.4) p=0.004
Non-cardiac congenital anomaly*	No	48 (83%)	131 (91%)	2.0 (0.8 to 5.6) p=0.1	6.2 (1.8 to 21.4) p=0.004

Additionally adjusted for the presence of abdominal wall erythema or discolouration at the time of presentation, which was retained in the model but was not statistically significantly associated with 1-year mortality.
*Based on number of infants with complete information for variable.
NEC, necrotising enterocolitis.