Which blood cutoff value should be used for vitamin A deficiency in children aged 3-10 years? A systematic review.

CONTEXT: Blood cutoff values for vitamin A deficiency in children aged 3-10 years have not been addressed in the literature.

OBJECTIVE

To identify blood retinol concentrations for determining severe vitamin A deficiency in children aged 3-10 years.

DATA SOURCES: The MEDLINE, Web of Science, Embase, and Scopus databases were searched.

DATA EXTRACTION: Two reviewers independently extracted article data and assessed quality.

DATA ANALYSIS: The hierarchical summary receiver operating characteristic models were applied for the diagnostic accuracy meta-analysis. This review is registered at PROSPERO (identifier: CRD42020149367).

RESULTS

A total of 15 articles met the eligibility criteria, and 9 were included in the diagnostic accuracy meta-analysis. The summary estimates (95%CI) were: Sensitivity, 0.39 (0.20-0.62); specificity, 0.79 (0.65-0.88); positive likelihood ratio, 1.85 (1.33-2.57); and negative likelihood ratio, 0.77 (0.60-0.99). The area under the curve of the overall analysis was 0.68 (95%CI 0.63-0.72).

CONCLUSIONS

Blood retinol concentrations have low diagnostic accuracy for severe vitamin A deficiency in children aged 3-10 years. Therefore, there is unclear evidence about the preferable cutoff point for determining severe vitamin A deficiency in children in this age group.