Registration in the international prospective register of systematic reviews (PROSPERO) of systematic review protocols was associated with increased review quality.

OBJECTIVES: A priori registration of systematic review protocols in international prospective register of systematic reviews (PROSPERO) can help reduce selective reporting of outcomes. The aim of this study was to assess the association between registration of orthodontic systematic reviews in PROSPERO and review quality with the Assessment of Multiple Systematic Reviews (AMSTAR) tool.

STUDY DESIGN AND SETTING: Seven databases were searched for systematic reviews with/without meta-analysis in orthodontics published between 2012 and 2016. After duplicate study selection and data extraction, the quality of identified reviews was assessed in duplicate with the AMSTAR tool. Descriptive statistics of medians and interquartile ranges (IQRs) and chi-square/Fisher exact tests were calculated. Univariable/multivariable linear regression modeling was implemented to assess the effect of review registration on %AMSTAR score at α of 5%.

RESULTS: A total of 182 orthodontic systematic reviews were identified, 37 (20.3%) of which were registered. Considerable differences were seen in AMSTAR between registered (median = 86.4%; IQR = 77.3-95.5%) and nonregistered reviews (median = 72.7%; IQR = 59.1-81.8%). After adjustment, registration in PROSPERO was associated with an average increase in %AMSTAR score of 6.6% (95% confidence interval = 1.0-12.3%).

CONCLUSION: Although only a small percentage of orthodontic systematic reviews was registered a priori in PROSPERO, registered reviews were of higher quality than nonregistered reviews.