Estado nutricional relativo ao ferro em lactentes com doença falciforme diagnosticoados pelo Programa Estadual de Triagem Neonatal de Minas Gerais

Abstract

Iron deficiency anemia is the most common nutritional disease in the world. Sickle cell disease is the most common inherited monogenic disease, characterized by a defect in the hemoglobin molecule. As this disease may be associated with iron overload, affected children would not be candidates for the administration of prophylactic iron and thus are excluded from the Iron Deficiency Anemia Prevention Program of the Brazilian Ministry of Health. No study that validates this decision ismeanwhile available. Objective: Evaluate iron nutritional status in infants to determine whether their exclusion from programs preventing iron deficiency is adequate. Methods: Retrospective cohort of children with sickle cell disease who were born in 2005-2006 and cared for in the Hemoglobinopathy Out-Patient Clinics, Hemominas Foundation, Belo Horizonte, Brazil. Results: 135 children (66 males and 69 females), with SS (77) and SC disease (58) took part in the study. The mean age when laboratory evaluation was done was 9.9 months (5.7-25.2). Mean values of laboratory tests were: Hemoglobin (Hb) 8.9 g/dL (4.3-12.5); white blood cell count 14.4x10³/ìL (6.7-38.2); platelet count 433x10³/ìL (135-1,362); reticulocyte count 7.7% (0.6-28); fetal hemoglobin (HbF) 16.9% (1-42); serum iron 14 ìg/dL (9-232); ferritin 64.6 ng/mL (4-462); IST 20.4% (2.4-44.1). 12,5% of the participants had received blood transfusion previously. There was no difference in neonatal weight, gestational age, gender, Hb and Hb F, white blood cell and platelet counts betweenchildren who received or not blood transfusions. Reticulocyte count was higher in the non-transfused group (12.8 vs 4; p<0.001). Probable iron deficiency indicators (MCV, MCH, serum iron, IST and ferritin) were lower in the non-transfused group (p<0.001). When only non-transfused children were analyzed (n=118), there was no difference in gender, gestational age or birth weight between SS and SC children. Whencompared with SS, SC children, as expected, had higher levels of hemoglobin and lower levels of HbF and reticulocyte count (p<0.001). Serum iron, ferritin and IST were all lower in SC children (p<0.001). Evaluation of iron deficiency indicators disclosed that 25.9% of them had MCV <70fL; 40% had MCH <23 pg; 11,9% had ferritin <10 ng/mL and 14.8% had IST <12%. Iron deficiency was more common in SC children (p<0.001 for MCV and MCH, p=0.014 for IST, and p=0.11 for ferritin). When two indexes were considered to define iron deficiency (MCV or MCH plus ferritin or IST) 17.8% of the children would have iron deficiency, mainly SC infants (p=0.003). When only those children who had not received any blood transfusion were analyzed 19.5% would be iron deficient. Only 15 children (11.3%) had high levels of ferritin (>142 ng/mL). Most of them had been previously transfused. Conclusions: Most infants with sickle cell disease are not iron deficient, but some do have iron deficiency. Iron overload was detected in about one tenth of the children, mainly associated with blood transfusions. This study indicates that sickle cell infants, particularly SC children, can be administered prophylactic iron, stopping the medication when the first blood transfusion occurs.