Results
Forty-four OG COSs focused on 26 topics. None met all the 25 standards of COS-STAR statement representing 18 items considered essential for transparent and complete reporting in all COS studies (range: 6.0-24.0, median: 14.0 ). The compliance rates for the 16 standards of methods and result sections ranged from 27.3% - 68.2%. Total COS-STAR compliance items of OG COSs with the prior protocol was significantly higher than without prior protocol (MD= 3.846, 95% CI: 0.835 - 6.858, P= 0.012). None of the OG COSs met all the 12 criteria of COS-STAD minimum standards (range: 3.0-11.0, median: 5.0). The compliance rates for all three standards of stakeholders involved and all four standards of the consensus process were lower than 60%.