A randomised controlled trial of iodine supplementation in extreme preterm infants

A randomised controlled trial of iodine supplementation in extreme preterm infants

Content Introduction o What is transient hypothyroxinaemia? o Why is this important? o Causes of transient hypothyroxinaemia o Why is Iodine important? o How much Iodine does the preterm infant need? I2S2 Study o Study design o Hypothesis o Outcome measures o Sample size How can you help Where to find more information

Transient hypothyroxinaemia transient = temporary hypo = low thyroxin = thyroxine aemia = in the blood

Why is transient hypothyroxinaemia important? Thyroid hormone is important for normal brain growth and development during gestation and until 2 years of age The only known use of iodine in the human is for the production of thyroid hormone

Transient hypothyroxinaemia Hypothyroxinaemia: is characterised by temporary postnatal reduction in levels of TSH, T4, FT4 is the commonest thyroid dysfunction in preterm infants is associated with neurodevelopmental delay of the infant (Meijer et al Arch Dis Child 1992; den Ouden et al Ped Res 1996 Reuss et al NEJM 1996; Lucas et al BMJ 1996)

loss of maternal-placental thyroid hormone transfer immaturity of hypothalamic-pituitary-thyroid axis non-thyroidal illness iodine deficiency Possible causes of transient Hypothyroxinaemia include: iodine excess and overload toxicity e.g. via contrast medium, surgery

Why is iodine important? The only known use for iodine in the body is for the production of thyroid hormones Iodine is stored in the thyroid gland The premature infant only has enough Iodine stored for approximately 2-3 days Thyroid hormones is very important for brain development

How much Iodine does the premature infant need? The recommended iodine intake for a term infant is 12 mcg/kg/day Studies have shown the premature infant needs 30-40 mcg/kg/day However parenteral nutrition only has 1 mcg/kg/day of iodine

I2 = I 2 S2 = Supplementation study

Infant iodine supplementation study Study Design - randomised, triple blind, controlled trial Intervention - sodium iodide versus placebo (sodium chloride); 30 µg/kg/day until 34 +0 (corrected) weeks; parenteral / enteral route Eligibility & recruitment - all infants 30 +6 weeks gestation, 42 hours of birth, informed consent

Infant iodine supplementation study Hypothesis - Iodine supplementation of parenterally fed extreme preterm infants improves neurodevelopmental outcome at 2 years Primary outcome measures - Neurodevelopmental outcome at 2.0 years corrected age Secondary outcome measures - Levels of T4, TSH and TBG - Incidences of non-thyroidal illness and drug usage - Respiratory function, hearing/visual disability, cause of death

Infant iodine supplementation study Phase 1 (NICU) - T4, TBG and TSH measured on postnatal days 7,14, 28 & 34 weeks corrected weeks; case report forms illness, drugs, iodine exposure etc Phase 2 (Hospital) - neurodevelopmental assessment, including Bayley Scales III at 2.0 years corrected age

Infant iodine supplementation study Sample size 1500 infants from 17 recruiting hospitals across the UK and Ireland Birmingham Heartlands Hospital Birmingham City Hospital Birmingham Women s Hospital Royal Berkshire Hospital, Reading Southern General Hospital, Glasgow James Cook University Hospital, Middlesbrough Queen s Medical Centre, Nottingham Ninewells Hospital and Medical School, Dundee Ayrshire Maternity Unit, Crosshouse Princess Royal Maternity Hospital, Glasgow Jessop Wing, Sheffield Teaching Hospital Wishaw General Hospital Royal Maternity Hospital, Belfast Sunderland Royal Infirmary, Nottingham City Hospital Royal Victoria Hospital, Newcastle Derby City Hospital, Derby

How can you help? We need you to help identify the infants that may be eligible for the study. Give parents the information leaflet and notify the I2S2 nurse or the Investigator that there is potential infant in the unit we only have 42 hours form birth to consent, enter and randomise an infant Completing the Guthrie/blood spot cards on day 7, 14, 28 and 34 weeks

Where to find more information The I2S2 Document box contains: Guidance sheets Completion guides for the documentation Study documents i.e. Case report forms The trial protocol Contact details The I2S2 Nurse communication book

Contacts Dr Fiona Williams Coordinating Investigator Tel: 01382 420117 E: f.l.r.williams@cpse.dundee.ac.uk Deirdre Thom I2S2 Neonatal Nurse Coordinator Tel: 01382 420124 Mobile: 07507 631 530 E: d.thom@cpse.dundee.ac.uk Kayleigh Morgan Trial Coordinator (NPEU CTU) Tel: 01865 617923 E: Kayleigh.Morgan@npeu.ox.ac.uk