Statistical analysis plan for the Prenatal Iodine Supplementation and Early Childhood Neurodevelopment (PoppiE) randomised controlled trial

Table 3 Primary and secondary trial outcomes

#	Outcome	Time-point measured	Variable type
	Primary
1	Bayley-IV^a Cognitive Scale Score	24 months	Continuous
	Secondary infant
2	Bayley-IV Cognitive Scale Score < 85	24 months	Binary
3	Bayley-IV Motor Scale Score	24 months	Continuous
4	Bayley-IV Motor Scale Score < 85	24 months	Binary
5	Bayley-IV Language Scale Score	24 months	Continuous
6	Bayley-IV Language Scale Score < 85	24 months	Binary
7	ITSEA externalising T score	24 months	Continuous
8	ITSEA internalising T score	24 months	Continuous
9	ITSEA dysregulation T score	24 months	Continuous
10	ITSEA competence T score	24 months	Continuous
11	ITSEA externalising T score ≥ 65	24 months	Binary
12	ITSEA internalising T score ≥ 65	24 months	Binary
13	ITSEA dysregulation T score ≥ 65	24 months	Binary
14	ITSEA competence T score ≤ 35	24 months	Binary
15	Weight z-score^b	24 months	Continuous
16	Length z-score^b	24 months	Continuous
17	Head circumference z-score^b	24 months	Continuous
18	Weight z-score^b	Birth	Continuous
19	Length z-score^b	Birth	Continuous
20	Head circumference z-score^b	Birth	Continuous
21	Length of gestation (days)	Birth	Continuous
22	Preterm birth < 37 weeks of gestation	Birth	Binary
23	Thyroid-stimulating hormone level^c	Birth	Continuous
24	Admission to special care nursery	Birth hospitalisation	Binary
	Secondary maternal
25	Hypertension/pre-eclampsia	Pregnancy	Binary
26	Gestational diabetes	Pregnancy	Binary
27	Vaginal delivery	Birth	Binary
28	Postpartum haemorrhage	Postpartum stage	Binary

Abbreviations: ITSEA Infant Toddler Social Emotional Assessment
^aIf a Bayley-IV assessment is unavailable, scores of an alternative robust developmental assessment with an age-standardised cognitive score will be accepted, if available (e.g. earlier versions of the Bayley scales or the Wechsler Preschool and Primary Scale of Intelligence)
^bCalculated according to WHO growth standards based on an average of 2 measures (average of closest 2 measures if a 3rd measure taken)
^cMeasured only in infants from South Australia

ISSN: 1745-6215