Data extraction and quality assessment
Two researchers independently collected information from each trial as follows: author, publication year, treatments per group, sample size, baseline Hb levels, duration of treatment, mean age, sex, efficacy, and safety results [changes in AEs, SAEs, Hb (ΔHb), Hb response, Δhepcidin, ΔTSAT, ΔTIBC, ΔFerritin, Δserum iron]. AEs and SAEs were the primary outcomes. The Cochrane tool will assess the risk of bias in clinical trials. Five domains were evaluated: randomization, deviations from intended interventions, missing data, outcome measurement, and selection of the reported result. Each domain was assigned a judgment of high risk of bias, low risk of bias, or some concerns. The Cochrane Handbook V.5.1.0, Chapter 8, was followed strictly to make the judgment for each domain.