Table 2 Assessing risk of bias of the included studies by validated Jadad 5-point scale
Author | Publication year | Country | Sample size (n) | Study Design | Randomization (0–2 points) | Double-blind (0–2 points) | Drop-outs and withdrawals (0–1 points) | Jadad score |
|---|---|---|---|---|---|---|---|---|
Sprague [27] | 2003 | USA | 263 | multicenter, double-blind, parallel | 1 | 2 | 1 | 4 |
Gafor [26] | 2009 | Malaysia | 25 | single-center, open-labelled, parallel | 1 | 0 | 1 | 2 |
Lund [25] | 2010 | USA | 18 | single-center, double-blind, crossover | 1 | 2 | 1 | 4 |
Hansen [24] | 2011 | Denmark | 86 | multicenter, open-labelled, crossover | 2 | 0 | 1 | 3 |
Ong [23] | 2013 | Malaysia | 66 | multicentre, open-labelled, parallel | 1 | 0 | 1 | 2 |
Jamaluddin [22] | 2014 | Malaysia | 26 | single-center, open-labelled, parallel | 1 | 0 | 1 | 2 |
Akizawa [21] | 2015 | Japan | 255 | multicenter, double-blind, parallel | 1 | 2 | 1 | 4 |
Veceric [28] | 2016 | Slovenia | 20 | single-center, open-labelled, parallel | 1 | 0 | 0 | 1 |