Table 3.

Results from the four models for mortality 30 and 90 days after ICU admission.

Models: 30 days	Description	Deficient B12 OR (95% CI)	P-value	High B12 OR (95% CI)	P-value
Model 1	B12 only	0.52 (0.16, 1.69)	0.2743	2.83 (2.13, 3.76)	<0.0001
Model 2	+Demographics	0.65 (0.19, 2.16)	0.4776	3.12 (2.31, 4.20)	<0.0001
Model 3	+Other potential confounders	0.89 (0.22, 3.57)	0.8651	1.93 (1.38, 2.72)	0.0001
Model 4	+Liver function and diseases	1.32 (0.32, 5.52)	0.7033	1.18 (0.81, 1.72)	0.3890
Models: 90 days
Model 1	B12 only	0.49 (0.17, 1.39)	0.1790	2.72 (2.08, 3.55)	<0.0001
Model 2	+Demographics	0.58 (0.20, 1.67)	0.3098	3.09 (2.33, 4.09)	<0.0001
Model 3	+Other potential confounders	0.99 (0.30, 3.30)	0.9919	1.97 (1.43, 2.71)	<0.0001
Model 4	+Liver function and diseases	1.30 (0.37, 4.53)	0.6774	1.20 (0.84, 1.71)	0.3077

Table 3 shows the model building procedure. In order to demonstrate the attenuation of the effect of B12 on mortality, we added variables to the B12 predictor sequentially to create the final, fully-adjusted model (“model 4”).Model 1 includes B12 only; model 2 includes B12 and demographic variables; model 3 includes B12, demographic, and other potentially confounding factors; and model 4 includes B12, demographic variables, other potential confounders, and liver function and disease (see Table 4 for details). The odds ratio compares the risk of the deficient or high B12 group to the mid-range B12 group.