title: Diagnostic accuracy of hemoglobin for iron deficiency in pregnancy: disclosing results of a cited clinical trial.
abstract: OBJECTIVE
  To analyze the accuracy of hemoglobin (Hb) concentrations as a diagnostic indicator of iron deficiency in pregnant women and to measure the efficacy of oral iron therapy using Hb z-scores rather than Hb absolute values.
  
  
  METHODS
  The sensitivity and specificity of Hb < 11.0 g/dL, and its receiver operating characteristic (ROC) curve, in the diagnosis of iron deficiency (serum ferritin (SF) < 12.0 ng/mL) were determined in 318 women in their second trimester of pregnancy who had been screened for a clinical trial conducted in 2001 in Northeast Brazil. A secondary analysis of iron therapy efficacy was carried out using data from the trial's three different treatments (60 mg of oral iron once per week (n = 46), twice per week (n = 50), and once per day (n = 44)). The mean differences between post- and pre-treatment Hb absolute values (g/dL) and z-scores (standard deviation (SD)) were calculated for the three treatment groups for study participants with and without iron deficiency.
  
  
  RESULTS
  Hb sensitivity, specificity, and area under the ROC curve were 60.7%, 44.3%, and 0.54 respectively. Women without iron deficiency showed improvements in Hb absolute values (as in the clinical trial's overall results) but did not have improved Hb z-scores (with scores of - 0.6 SD (95% confidence interval (CI): - 0.99, - 0.28); - 0.2 SD (95% CI: - 0.47, 0.08); and - 0.1 SD (95% CI: - 0.33, 0.18) for weekly, twice-per-week, and daily iron treatment schemes respectively). In contrast, iron-deficient women treated with the intermittent schemes had reductions in both Hb absolute values and Hb z-scores, respectively: weekly = - 0.42 g/dL (95% CI: - 0.72, - 0.12) and - 1.4 SD (95% CI: - 1.74, - 0.99); twice per week = - 0.14 g/dL (95% CI: - 0.46, 0.17) and - 1.1 SD (95% CI: - 1.44, - 0.75).
  
  
  CONCLUSIONS
  These analyses revealed that Hb concentrations were not an accurate indicator of either iron needs or iron-therapy response in pregnant women.
authors.affiliation: Nutrition Research Group, Instituto de Medicina Integral Prof. Fernando Figueira, Recife, PE, Brazil, cristiane.bresani@inss.gov.br.
authors.forename: Cristiane C Bresani
authors.initials: CC
authors.lastname: Salvi
authors.forename: Maria Cynthia
authors.initials: MC
authors.lastname: Braga
authors.forename: Malaquias
authors.initials: M
authors.lastname: Batista Filho
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000097:blood* / Q000175:diagnosis* / Q000188:drug therapy; D002986:Clinical Trials as Topic; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000097:blood* / Q000175:diagnosis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D006454:Hemoglobins