USING DENTAL PATIENT-REPORTED OUTCOMES (dPROs) IN META-ANALYSES: A SCOPING REVIEW AND METHODOLOGICAL INVESTIGATION

Many studies use dental patient-reported outcomes (dPROs) to evaluate treatments and interventions. However, the consensus on the methodology for combining results of dPROs for meta-analysis has not yet been fully established or widely discussed. The aim of this study is to conduct a scoping review for the methodological issues and difficulties specific to meta-analysis of dPROs and to put forward recommendations for improving quality of meta-analyses of dPRO. We searched the Google Scholar and PubMed databases and identified meta-analysis with dPROs in English. A total of 22 meta-analyses were included in our scoping review, and their characteristics, such as reported outcomes, questionnaires, and effect measures, were extracted. We identified several methodological issues within current literature: (1) synthesizing results from studies with different rating scales; (2) meta-analyses with few studies; (3) the interpretation of standardized mean difference; (4) including studies of different cut-off values in a meta-analysis; and (5) systematic errors due to different instruments. According to each issue mentioned, we provided guidance and recommendations on how to resolve those issues, including using the same Likert scale, conducting an overall and subgroup meta-analysis, using a random-effects model in a meta-analysis, etc. More efforts are required to improve the conduct and interpretation of meta-analyses on dPROs.