A utilidade dos índices eritrocitários e da ferritina sérica na indicação de ferroterapia na predição da eficácia terapêutica do ferro oral durante a gravidez: a inadequação do conceito Gaussiano da normalidade para o manejo dos casos de anemia ferropriva materna

Abstract

Objective: to estimate the accuracy of the erythrocyte indices (red blood cell count, haemoglobin concentration-Hb, haematocrit-HTC, mean corpuscular volume-MCV, mean corpuscular haemoglobin-MCH, mean corpuscular haemoglobin concentration-MCHC, red blood cell distribution width-RDW, reticulocyte count) and the serum ferritin (SF) for iron deficiency diagnosis in pregnant women. Methods: the thesis comprised three studies. The first study evaluated the baseline data from 347 pregnant women before the iron supplementation of a clinical trial performed between May 2000 and June 2001, and determined the distribution curves of the erythrocyte indices and their accuracy parameters versus SF 12 ng/mL. The second study examined longitudinal data from the 140 women enrolled for the preceding trial to receive 60 mg of oral iron (weekly, twice a week or daily) and each treatment group was subdivided into strata with and without iron deficiency (SF 12 ng/mL) to compare the therapeutic responses (means of differences-MD between pre and post-treatment Hb) in absolute values (g/dL) and in Z-scores (standard deviation-SD). The original trial of this thesis was carried out between August 2011 and October 2012 and had a phase III validation design with 144 anemic pregnant women (Hb 11 g/dL) treated with 80 mg of elemental iron daily during 28 to 90 days, to calculate the accuracy parameters of erythrocyte indices and SF pre-treatment versus the gold-standard responsiveness to therapeutic test with oral iron, which was measured by the differences between the Hb Z-scores before-and-after the trial. Results: the mean value of red blood cell count (3.7 1012 cells/L), HTC (32.9 por cento) and Hb (10.8 g/dL) were below their reference cutoff points. The curves of morphological indices were not adjusted to the Normal distribution with the following mean values: MCV