Table 2.

Independent risk factors for prolonged intensive care unit stay

	Co-efficient	SE	Adjusted OR (95% CI)	P Value
Renal dysfunction	1.6066	0.2162	4.99 (3.3 – 7.6)	<0.001
Angina class IV	0.4950	0.1048	1.64 (1.3 – 2.0)	<0.001
Ejection fraction <30%	0.7771	0.1397	2.17 (1.6 – 2.9)	<0.001
Peripheral vascular disease	0.4809	0.1288	1.62 (1.2 – 2.1)	<0.001
BMI ≥ 30 and <35 kg/m2	0.3338	0.1194	1.39 (1.1 – 1.8)	0.005
BMI ≥ 35 kg/m2	0.7436	0.1935	2.1 (1.4 – 3.1)	<0.001
Age ≥ 70 and <75 years	0.5313	0.1283	1.7 (1.3 – 2.2)	<0.001
Age ≥ 75 years	0.7972	0.1640	2.22 (1.6 – 3.1)	<0.001
Current smoker	0.5238	0.1291	1.69 (1.3 – 2.2)	<.0001
Diabetes	0.4381	0.1207	1.55 (1.2 – 2.0)	<0.001
Emergent procedure	0.7124	0.2510	2.04 (1.2 – 3.3)	0.004
Hypercholesterolaemia	0.3507	0.1282	1.42 (1.1 – 1.8)	0.006
Hypertension	0.2577	0.1039	1.29 (1.1 – 1.6)	0.013
Use of CPB	0.8904	0.1734	2.44 (1.7 – 3.4)	<0.001
Intercept	-4.4390

Calculation of predicted risk using patient data and logistic regression co-efficients:

Calculate the odds of prolonged intensive care unit stay = exp (-4.4390 + [1.6066 × renal dysfunction] + [0.4950 × angina class IV] + [0.7771 × ejection fraction <30%] + [0.4809 × peripheral vascular disease] + [0.3338 × BMI ≥ 30 and <35 kg/m2] + [0.7436 × BMI ≥ 35 kg/m2] + [0.5313 × age ≥ 70 and < 75 years] + [0.7972 × age ≥ 75 years] + [0.5238 × current smoker] + [0.4381 × diabetes] + [0.7124 × emergent procedure] + [0.3507 × hypercholesterolaemia] + [0.2577 × hypertension] + [0.8904 × use of CPB]).

Predicted risk of prolonged intensive care unit stay as a percentage = [odds/(1 + odds)] × 100.

SE, Standard Error; OR, Odds Ratio; CI, Confidence Intervals; BMI, Body Mass Index; CPB, Cardiopulmonary Bypass.