Table 2.

Multiple logistic regression demonstrating adjusted odds ratio for 28-day inpatient mortality categorized by metformin use and categorized lactate.^a

a) Model for all patients in the study cohort (n=1947)
Parameter	Lactate Stratum	n	Odds Ratio	95% C.I.	p
Non Metformin Users	<2.0 mmol/L	919		Referenceb
	2.0 – 3.9 mmol/L	606	1.27	0.92 – 1.78	0.15
	≥ 4.0 mmol/L	230	3.18	2.12 – 4.66	<0.01
Metformin Users	< 2.0 mmol/L	75	0.59	0.21 – 1.70	0.32
	2.0 – 3.9 mmol/L	85	0.77	0.34 – 1.78	0.54
	≥ 4.0 mmol/L	32	0.54	0.15 – 1.83	0.33

b) Model including only diabetics within the study cohort (n=535)
Parameter	Lactate Stratum	n	Odds Ratio	95% C.I.	p
Non Metformin Users	<2.0 mmol/L	168		Referenceb
	2.0 – 3.9 mmol/L	127	1.41	(0.72,2.78)	0.32
	≥ 4.0 mmol/L	48	3.68	(1.62,8.38)	<0.01
Metformin Users	< 2.0 mmol/L	75	0.60	(0.19,1.88)	0.38
	2.0 – 3.9 mmol/L	85	0.81	(0.32,2.07)	0.66
	≥ 4.0 mmol/L	32	0.60	(0.16,2.25)	0.45

^aThe model was adjusted for patient age (OR = 1.04 for every year older than 21, p < 0.01), modified PIRO score (OR = 1.11 for each point increase in scoring system, p < 0.01), and serum creatinine > 1.4 mg/dL (OR = 1.77, p = 0.01);

^bReference group: 21 year old subject with a lactate < 2.0 mmol/L not taking metformin.