Volume 3: Reporting of Systematic Reviews of Micronutrients and Health: A Critical Appraisal
Medical communities have effectively used systematic reviews to develop clinical and public health-practice guidelines. Use of this kind of review in nutrition applications is newer.
Background: The quality of nutrition-related systematic reviews (SR) is an unstudied but important factor affecting their usefulness.
Objective: To evaluate reporting quality of published SRs and identify areas for improvement.
Design: Descriptive and exploratory analyses of reporting quality (7 nutrition items and 28 SR reporting items) of all English-language SRs published through July 2007 linking micronutrients and health outcomes in humans. Factors that may to be associated with the reporting quality were also evaluated.
Results: We found 141 eligible SRs of 21 micronutrients. Ninety SRs that included only interventional studies met a higher proportion of our reporting criteria (median: 62 percent, interquartile range (IQR): 51 percent, 72 percent) than 31 SRs with only observational studies (median: 53 percent, IQR: 47 percent, 60 percent) or 20 SRs with both study designs (median: 47 percent, IQR: 39 percent, 52 percent) (P<0.001). SRs published after consensus reporting standards (since 2003) met a higher proportion of the reporting criteria than earlier SRs (median: 59 percent versus 50 percent, P=0.01); however, the reporting of nutrition variables remained unchanged (median: 38 percent versus 33 percent, P=0.7). The least-reported nutrition criteria were baseline nutrient exposures (28 percent) and impacts of the measurement errors from nutrition exposures (24 percent). Only 58 SRs (41 percent) used quality scales or checklists to assess the methodological quality of the primary studies included.
Conclusions: The reporting quality of SRs has improved 3 years after publication of SR reporting standards (since 2003), but the reporting of nutrition variables has not. Improved adherence to consensus methods and reporting standards should improve the utility of nutrition SRs.
Nutritional Research Series, Volume 3: Reporting of Systematic Reviews of Micronutrients and Health: A Critical Appraisal
Evidence-based Practice Center: Tufts EPC
Topic Sponsor: Office of Dietary Supplements, National Institutes of Health