Study Flow (N = 158)
| Characteristics | No. |
|---|---|
| Note: Randomized controlled trials reported in Annals of Internal Medicine, British Medical Journal, The Journal of the American Medical Association, The New England Journal of Medicine, and The Lancet between September 2006 and February 2007. | |
| a Results total to more than 48, as several trials were excluded for more than 1 reason. | |
| Excluded trialsa | 48 |
| No, incorrect, or not publicly accessible trial registration database recorded in the main publication | 11 |
| Registry did not record a primary outcome, or the outcome recorded was too vague to use | 20 |
| Publication was not the main report of the trial results | 23 |
| Included trials | |
| Information extracted: study reference and copy of study, trials registration reference and copy of registration, primary and secondary outcomes in the final report, primary and secondary outcomes in the trials registration database | 110 |