Table 3 Comparison between the Cochrane review and this study in terms of scope and impact on P value in mortality

Present study - Primary analysis

   Eight included trials (n = 8; Athens corrected*, Akershus, Goteborg-

0.84 (0.70 – 1.00)

P = 0.05

   Sahlgren, Perth, Trondheim, Joinville, Edinburgh, Umea)

Present study - Secondary analysis

   ✓ Inclusion of two unpublished trials

0.87 (0.74 – 1.03)

P = 0.12

   (n = 10 ; Same as above plus Goteborg-Ostra, Svendborg)

   ✓ Inclusion of trials with very short-term observation

0.86 (0.74 – 1.01)

P = 0.06

   (n = 12 ; Same as above plus Beijing, Stockholm)

   (i.e. All trials included in the Cochrane review, Athens corrected*)

The Cochrane review 2009

   ✓ Cochrane review – Analysis 2.1 subtotal

0.85 (0.72 – 0.99)

P = 0.03

   (n = 12; all trials mentioned above, Athens uncorrected)