Evaluation of oral iron supplementation in pediatric maintenance insomnia

Abstract

Iron deficiency anemia (IDA) is a very common problem that increases spontaneous nocturnal restless motor activity and night wakings during sleep. IDA has been linked to cognitive problems such as poor attention, lack of concentration and learning difficulties. We conducted a prospective and open-label study of children and adolescents with IDA (defined by serum ferritin under 50 ng/ml, iron deficiency and/or anemia) and maintenance insomnia (IM) with nocturnal restless activity and night waking, treated with oral iron supplementation to evaluate the efficacy of this treatment, administered during the course of clinical care. The study included 116 children and adolescents (67 boys and 49 girls) with IDA and MI who visited the Pediatric Sleep Unit. Sleep quality was assessed with PSQ, SDSC questionnaires and CGI-C. Blood tests were made in all patients; night-time polysomnography was performed in 46 cases. After IDA and MI diagnosis, oral iron supplementation (ferric sulfate) was administered to all children and adolescents (4 mg/kg/day; 325 mg/day after 12 yo). Blood parameters and sleep quality were reassessed 3–6 months after. Patient age at onset of symptoms ranged from 0.5 to 17 years (mean ± SD, 5.4 ± 4.1) and 2 groups were observed: with (I+) or without improvement. (I−). A positive family history of insomnia, PLM o RLS was recognized in 40 patients and RLS was found in 13 subjects (no differences related with improvement) but PLMD was more prevalent in I+ group (28% vs 13%; p = 0.09). Serum ferritin level before therapy was 5–96 ng/ml (30.3 ± 18.2) and oral iron supplementation was reported to be effective in 83.6% patients (85% highly effective, CGI-C 1 or 2). Lower serum iron levels were seen in patients with higher apnea/hipopnea index ( p : 0.077). Though serum ferritin and iron concentrations were not improvement related (I+ vs I−, p > 0.05), ferritin ”in range” (below 50 ng/ml but higher that lower normal limit) was strongly related with clinical improvement ( p = 0.001). The onset of treatment effect was approximately 3 months. Supplemental iron was consistently associated with less night waking and sleep quality improvement. Iron treatment has demonstrated to be effective in pediatric MI and IDA. We thank Dr. J. García-Sicilia (Department of Pediatrics) for helping us in coordinating Hospital Sleep Unit with Primary Care physicians.