Table 2.

Comparison of pooled one-month mortality by different variables

	Studies (n)	Placebo-treated patients (n)	Gender (M/F)	One-month death (n)	One-month mortality rate (%)	χ2	P value
Severity of disease
Unclassified	2	64	33/31	7	10.94	4.375	0.038
Moderate to severe	8	260	171/89	59	22.69
Geographical area(s)
US	5	156	119/37	35	22.44	0.791	0.409
Europe	5	168	85/83	31	18.45
Publication year
Before 1990	5	168	118/50	30	17.86	1.359	0.271
After 1991	5	156	86/70	36	23.08