Development and Validation of a Nutrition-Specific Set of Tools to Assess the Quality of Nutrition Studies

Abstract Objectives To develop and validate a set of 3 quality assessment instruments (QAls) for evaluating the quality of nutrition studies, for each of the commonly used study designs: (1) randomized controlled trials (RCTs), (2) prospective cohort, and (3) case-control studies. Methods The QAI development and validation process included 8 steps: 1) identify and evaluate existing general QAls for adaptation with nutrition-specific quality appraisal items; 2) scan the literature to identify nutrition-specific quality appraisal issues; 3) generate nutrition-specific items to be added to each of the general QAIs, adapt existing guidance for general items for nutrition applications and develop guidance for added nutrition items; 4) review, by two experts in clinical and population nutrition, of the modified general QAIs with added nutrition-specific items and guidance; 5) assess reliability and validity of the QAI for each study design; 6) improve the usability and feasibility, of the QAIs by considering feedback from the validation exercise to refine the wording of the guidance; 7) develop a worksheet to help evaluate, a priori, topic-specific methodology to address risk of bias; and 8) validate the final QAIs using five peer-reviewed studies identified from published systematic reviews with reported quality assessment. Agreement and reliability were determined for each QAI. Results Results of the validation show good to perfect agreement among evaluators for the overall study rating and across domains. When compared to the study quality assessment reported in the systematic review, nutrition- specific items had the greatest impact on study ratings, generally resulting in a downgrade of the overall rating. Conclusions A set of nutrition-specific QAls were developed to assess the quality and robustness of nutrition studies. These tools incorporate general quality issues of study design and conduct, as well as address recognised nutrition study-specific issues. They will improve consistency in how nutrition studies are assessed particularly in nutrition-related systematic reviews. This will contribute to the overall quality of assessment of diet and Funding Sources This work was supported by Health Canada.