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Table 3 Characteristics of trials (n = 189)

From: Journal impact factor, trial effect size, and methodological quality appear scantly related: a systematic review and meta-analysis

Mortality primary outcome10%
Statistically significant for mortality9%
Mortality reported in primary paper98%
Multicenter37%
Centers, mean number10
Domain
 Medicine43%
 Obstetrics14%
 Pediatrics21%
 Surgery22%
Country
 Canada/USA33%
 Europe53%
 Asia4%
 Other11%
Random sequence
 Unclear54%
 Y46%
 N1%
Allocation concealment, grade
 Adequate (A)34%
 Unclear (B)27%
 Inadequate (C)2%
 Not Used (D)37%
Double-blind39%
Analysis
 Unclear30%
 As treated29%
 As randomized41%
Publication year, mean1993
External funding
 Peer review47%
 Industry42%
 Not stated11%
Patients in analysis, mean number (median)563 (165)
Deaths, mean number (median)56 (21)