Use of GRADE in evidence syntheses published in high-impact-factor nutrition journals: A methodological survey

Objective: To identify and describe the use of the GRADE approach for rating the certainty of evidence in nutrition systematic reviews (SRs). Study design and setting: We systematically searched for SRs using GRADE that were published between 2015 and 2019 in the 10 nutrition journals with the highest impact factor according to the JCR 2018. Results: Out of 800 SRs, 55 SRs of randomized control trials (RCTs) and/or nonrandomized studies (NRSs) used GRADE. Fortyseven SRs (5.9%) rated the outcome specific certainty of evidence (n = 36 in 2018/2019). We identified a total of 465 certainty of evidence outcome ratings (n = 335 RCT ratings), ranging from very-low (28.8%) to low (41%), moderate (26.5%), and high (3.7%). Very-low and high certainty of evidence ratings accounted for 61.4% and 0.8% of ratings in SRs of NRSs, compared to 16.1% and 4.8% in SRs of RCTs. Certainty of evidence was downgraded mostly for risk of bias (37.8%) and imprecision (33%) in SRs of RCTs and for imprecision (32.7%), risk of bias (29.4%) and inconsistency (29%) in SRs of NRSs. Conclusion: Our study suggests a need for directing more attention toward strengthening acceptance of GRADE as well as building knowledge of the GRADE methodology in nutrition evidence synthesis. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study found that the use of the GRADE approach in nutrition systematic reviews is common, but there are still a proportion of evidence ratings that are low. Evidence certainty is mostly downgraded due to factors such as risk of bias and imprecision. The study suggests strengthening the acceptance and knowledge of the GRADE methodology in nutrition evidence synthesis.