Table 2.
Main quality assessment of included studies
| Year | Author | Study design | Description of randomization | Allocation concealment | Description of withdrawals | Blinding outcome assessment |
|---|---|---|---|---|---|---|
| 1978 | George J. Taylor | RCT | + | – | – | – |
| 1993 | Henry R. Halperin | RCT | + | – | – | – |
| 1998 | Edward T. Dickinson | RCT | + | – | + | – |
| 2006 | Christer Axelsson | Descriptive, non-randomised, controlled trial | – | – | + | – |
| 2006 | Al Hallstrom | RCT | + | – | + | – |
| 2006 | Marcus Eng Hock Ong | Phased, prospective cohort trial | – | – | + | – |
| 2010 | Lu Xiaoguang | RCT | – | – | – | – |
| 2011 | David Smekal | RCT | + | – | – | – |
| 2012 | Marcus Eng Hock Ong | Phased, prospective cohort trial | – | – | + | – |
| 2014 | Sten Rubertsson | RCT | + | – | + | – |
| 2015 | Gavin D Perkins | RCT | + | – | + | – |
| 2015 | Sebastian Zeiner | Prospective observational study | – | – | – | – |
RCT randomized controlled trial