. Author manuscript; available in PMC: 2011 Apr 1.

Published in final edited form as: Anesth Analg. 2009 Oct 9;111(4):862–869. doi: 10.1213/ANE.0b013e3181b7908c

Table 3.

Multivariable Predictors of Preoperative Antithrombin Activity

Predictor	Univariate estimate	Predictors of preoperative AT activity (U/mL) (n = 1194^a; r² = 0.168)
Predictor	Univariate estimate	Multivariate estimate	Standard error of multivariate estimate	P
Age (1 yr increment)	−0.0020	−0.0022	0.0004	<0.0001
Gender (female)	0.0288	0.0177	0.0059	0.0028
Race (Caucasian)	−0.0078	−0.0026	0.0054	0.624
Weight (1 kg increment)	−0.0003	−0.0003	0.0002	0.233
Height (1 cm increment)	−0.0007	−0.0031	0.0005	0.568
Institution	0.0183	0.0081	0.0053	0.129
Previous MI (Y)	−0.0273	−0.0104	0.0036	0.004
Preoperative platelet count (10 × 10⁹/mL increment)	0.0023	0.0013	0.0005	0.006
Preoperative PTT (1 s increment)	−0.0014	−0.0008	0.0002	<0.0001
Preoperative heparin use	−0.0863	−0.0352	0.0042	<0.0001
Preoperative diuretic use	0.0275	0.0147	0.0042	0.0005

209 subjects were missing one or more of the model’s predictor variables and are not included in this analysis.

AT = antithrombin; MI = myocardial infarction; PTT = partial thromboplastin time.