Table 2. Baseline demographics of study population.

RR=Relative Risk; SMD=Standardized Mean Difference

Baseline Characteristic	Mg supplementation	Placebo	N	Studies (n)	RR or SMD (95% CI)	Heterogeneity P value	Heterogeneity I2 (%)	P for overall effect
Age, yrs	62.3	61.6	2,008	15	0.21 (0.03 to 0.40)	0.02	75.58	<0.0001
Males, %	79.6	78.4	1,986	16	1.02 (0.98 to 1.06)	0.97	0	0.37
Hypertension, %	49.1	48.0	669	7	0.96 (0.86 to 1.09)	0.73	0	0.55
Diabetes mellitus, %	21.0	18.0	1,169	9	1.11 (0.73 to 1.67)	0.02	53.99	0.63
History of myocardial infarction, %	47.3	48.6	966	11	0.97 (0.86 to 1.10)	0.88	0	0.62
Preoperative use of beta-blockers, %	63.0	67.8	1,723	15	0.95 (0.87 to 1.03)	0.06	39.26	0.21
Need for vasopressors post-surgery, %	29.5	31.9	958	7	0.83 (0.62 to 1.12)	0.11	42.09	0.22