NUQUEST-NUtrition QUality Evaluation Strengthening Tools: development of tools for the evaluation of risk of bias in nutrition studies

Abstract

Background: Dietary exposure assessments are a critical issue in evaluating human nutrition studies; however, nutrition-specific criteria are not consistently included in existing bias assessment tools.

Objectives: Our objective was to develop a set of risk of bias (RoB) tools that integrated nutrition-specific criteria into validated generic assessment tools to address RoB issues, including those specific to dietary exposure assessment.

Methods: The Nutrition QUality Evaluation Strengthening Tools (NUQUEST) development and validation process included 8 steps. The first steps identified 1) a development strategy; 2) generic assessment tools with demonstrated validity; and 3) nutrition-specific appraisal issues. This was followed by 4) generation of nutrition-specific items and 5) development of guidance to aid users of NUQUEST. The final steps used established ratings of selected studies and feedback from independent raters to 6) assess reliability and validity; 7) assess formatting and usability; and 8) finalize NUQUEST.

Results: NUQUEST is based on the Scottish Intercollegiate Guidelines Network checklists for randomized controlled trials, cohort studies, and case-control studies. Using a purposive sample of 45 studies representing the 3 study designs, interrater reliability was high (Cohen's κ: 0.73; 95% CI: 0.52, 0.93) across all tools and at least moderate for individual tools (range: 0.57-1.00). The use of a worksheet improved usability and consistency of overall interrater agreement across all study designs (40% without worksheet, 80%-100% with worksheet). When compared to published ratings, NUQUEST ratings for evaluated studies demonstrated high concurrent validity (93% perfect or near-perfect agreement). Where there was disagreement, the nutrition-specific component was a contributing factor in discerning exposure methodological issues.

Conclusions: NUQUEST integrates nutrition-specific criteria with generic criteria from assessment tools with demonstrated reliability and validity. NUQUEST represents a consistent and transparent approach for evaluating RoB issues related to dietary exposure assessment commonly encountered in human nutrition studies.

Keywords: case-control study; cohort study; nutrition; quality assessment instrument; randomized controlled trial; risk of bias tool.

FIGURE 1

Approach for the development of NUQUEST, guidance and worksheet. NUQUEST, NUtrition QUality Evaluation Strengthening Tools; RCT, randomized controlled trial.

FIGURE 2

Nutrition QUality Evaluation Strengthening Tools (NUQUEST) ratings for individual sections and overall and the overall rating from the original SRs. ¹NUQUEST assessments are by section and overall by study: ● good, where almost all criteria are met, little or no concern, and low RoB; ● neutral, where most criteria are met, there are some flaws, and moderate RoB; and ○ poor, where either most or all criteria are not met, there are significant flaws, and high RoB. ²Selection = selection of participants (RCT)/selection of cohorts (cohort)/creation of study groups (case-control). ³Comparability = comparability of study groups (RCT, case-control)/comparability of cohorts (cohort). ⁴Ascertainment = ascertainment of outcomes (RCT, cohort)/exposure ascertainment (case-control). ⁵Nutrition = nutrition-specific (RCT, cohort, case-control). ⁶Overall = overall NUQUEST rating. ⁷Assessed using the NUQUEST worksheet. ⁸Evaluated by the Cochrane RoB Tool modified for nutrition studies. ⁹Evaluated by the Cochrane RoB Tool. ¹⁰Evaluated by the NOS modified for nutrition cohort studies. ¹¹Evaluated by the NOS. ¹²Evaluated by the JBI critical appraisal tool for case-control studies. ¹³Evaluated by the JBI critical appraisal tool for cross-sectional studies. Because the original SRs used a variety of tools to assess RoB, the original scores were recoded to “poor, neutral, and good” to allow for comparison to NUQUEST scores. Recoding for the Cochrane RoB Tool or the NOS modified for nutrition cohort studies was as follows: low RoB, it was assigned good ●; moderate RoB, it was assigned neutral ; and high RoB, it was assigned poor ○. Recoding for the NOS was as follows: 1–3, it was assigned ○; 4–6, it was assigned ; and 7–9, it was assigned ●. Recoding for the JBI cross-sectional tool was as follows: 1–4, it was assigned ○; and 5–8, it was assigned ●. Recoding for the JBI case-control tool was as follows: 1–3, it was assigned ○; 4–7, it was assigned ●; and 8–10, it was assigned ●. Where the authors of the original SR did not make an overall RoB judgment, section-specific judgments and related text within the report were examined to assign an overall RoB assessment by 2 members of the working group. ID, identification; JBI, Joanna Briggs Institute; NOS, Newcastle-Ottawa Scale; RCT, randomized controlled trial; RoB, risk of bias; SR, systematic review.