The course of anaemia in children and adolescents with Crohn's disease included in a prospective registry.

Aim: The aim of this study is to determine the prevalence and evolution of anaemia in prospectively followed children and adolescents diagnosed with Crohn's disease (CD).
Methods: The BELCRO registry (inclusion May 2008-April 2010), describing current clinical treatment practice of children diagnosed with CD, provided data on age, height, body mass index (BMI), paediatric Crohn's disease activity index (PCDAI), therapy and haemoglobin (Hb) at diagnosis 12 and 24 months follow-up. Anaemia was defined as Hb < -2 sd, while severe anaemia was defined as Hb < -4 sd. Patients were classified as child ≤13 and adolescent >13 years of age.
Result: Ninety-six were included, 13 dropped out due to insufficient Hb data (37 females/46 males; median age 13.3 years, range 2.2-17.8 years). At diagnosis, the median Hb sd was -2.66 (-8.4; 1.07) and was correlated with the PCDAI (p = 0.013). At diagnosis, 51/83 (61%) were anaemic and all had active disease. Hb z-score significantly improved (p < 0.0001) but 26/68 (38%) remained anaemic at 12 months and 29/76 (38%) at 24 months of follow-up. The correlation to the PCDAI disappeared. At 24 months, children were more likely to be anaemic. There was no difference in iron dose nor duration of iron supplements between children and adolescents. Iron treatment was more readily given to patients presenting with anaemia. Hb did not differ between patients with (n = 28) or without iron supplements. Half of the patients with persisting anaemia were given iron supplements, of which, only three were given intravenously.
Conclusion: Anaemia remains an important extra-intestinal manifestation of CD in children. Physicians, lacking optimal treatment strategies, undertreat their patients.