Improving the reporting quality of intervention trials addressing the inter-individual variability in response to the consumption of plant bioactives: quality index and recommendations

Abstract

Key messages The reporting quality of human studies on inter-individual variation in response to plant bioactives is generally low and should be significantly improved. There is no specific guidance for reporting studies on inter-individual variation in response to plant bioactives. The assessment of reporting quality using a scale approach is considered a valuable tool in assessing compliance with the recommendations in the submission phase or during the reviewing process. It also provides a quantitative measure of the quality of studies to be used in meta-analysis. Eleven reporting criteria were developed and supported by detailed definitions and guidance for their scoring. The POSITIVe quality index was tested and demonstrated to be valid, reliable, and responsive. The use of the quality index and its supporting explanatory material (dictionary) as a guide for researchers, peer-reviewers, and journal editors will foster further complete and transparent reporting of data on inter-individual variability. The criteria used in the quality index can serve as additional guidance to inform the design and conduction of further studies on inter-individual variations in response to plant bioactives. Better reporting is expected to lead to a better understanding of the mechanisms and factors involved and thus better study designs with greater impact on policies and practice. Purpose The quality of the study design and data reporting in human trials dealing with the inter-individual variability in response to the consumption of plant bioactives is, in general, low. There is a lack of recommendations supporting the scientific community on this topic. This study aimed at developing a quality index to assist the assessment of the reporting quality of intervention trials addressing the inter-individual variability in response to plant bioactive consumption. Recommendations for better designing and reporting studies were discussed. Methods The selection of the parameters used for the development of the quality index was carried out in agreement with the scientific community through a survey. Parameters were defined, grouped into categories, and scored for different quality levels. The applicability of the scoring system was tested in terms of consistency and effort, and its validity was assessed by comparison with a simultaneous evaluation by experts' criteria. Results The "POSITIVe quality index" included 11 reporting criteria grouped into four categories (Statistics, Reporting, Data presentation, and Individual data availability). It was supported by detailed definitions and guidance for their scoring. The quality index score was tested, and the index demonstrated to be valid, reliable, and responsive. Conclusions The evaluation of the reporting quality of studies addressing inter-individual variability in response to plant bioactives highlighted the aspects requiring major improvements. Specific tools and recommendations favoring a complete and transparent reporting on inter-individual variability have been provided to support the scientific community on this field.