Table 1. Demographic, Cardiac Risk And Surgical Risk Factors And Postoperative Physiological Data For The Derivation And Validation Cohorts. Values Are Median (IQR) Or Number (Proportion).

Characteristic	Derivation cohort (n = 631)	Validation cohort (n = 198)	p-value
Pre-operative risk factors
Age	62 (54–68)	61 (53–70)	0.429**
Gender (male)	423 (67)	136 (68.7)	0.728*
Diabetic	217 (34.4)	81 (40.9)	0.107*
Hypertensive	400 (63.5)	140 (70.1)	0.48*
Smoker	375 (59.5)	142 (72.4)	0.001*
Ischaemic heart disease	347 (55)	126 (64.3)	0.026*
Congestive cardiac failure	9 (1.4)	4 (2.1)	0.517*
Stroke	123 (19.5)	50 (25.4)	0.088*
Creatinine > 180 μmol.l-1	63 (10.5)	7 (4.1)	0.010*
Pre-operative glucose	5.9 (5.1–8.5)	5.9 (4–8)	0.627**
Pre-operative haemoglobin	12.7 (11.2–14.3)	12.9 (11–14)	0.457**
Pre-operative chronic medical therapy
Statin therapy	103 (16.3 )	30 (15.2)	0.740*
Chronic beta-blockade	152 (24.1)	43 (21.7)	0.565*
Surgical risk factors
Supra-inguinal surgery	80 (12.7%)	30 (15.2%)	0.401*
Duration of surgery (minutes)	103 (70-130)	113 (70-154)	0.203**
Surgery out of hours	52 (8.2%)	20 (10.1%)	0.249*
Postoperative physiological data and risk factors
Withdrawal of chronic beta-blockade	96 (15.5%)	10 (5.1%)	< 0.001*
Mean last heart rate	83 (73–95)	79 (71–90)	0.002**
SBP < 100 or > 179 mmHg	52 (8.5)	10 (6.3)	0.362*
Mean last SBP	127 (112–141)	128 (117–145)	0.071**
Mean last DBP	81 (69–116)	79 (69–120)	0.965**
Postoperative glucose	7.9 (6.1–10)	7.8 (6.9–9.3)	0.627**
Postoperative haemoglobin	10.3 (8–11.8)	10.3 (9.3–11.5)	0.557**

*Fisher’s exact test; **Mann–Whitney test; SBP: systolic blood pressure; DBP: diastolic blood pressure; IQR: interquartile range.