Table 1. Incidence (per 100 births) for conditions and procedures indicative of neonatal morbidity.

	Incidence before first hospital discharge in HES (%), by gestational age group*			Incidence before first hospital discharge (%) reported by lainet al8 by gestational age group
Component	24–33 weeks (n=8280)	34–36 weeks (n=25 272)	37–43 weeks (n=4 50 455)	24–33 weeks (n=9352)	34–36 weeks (n=24 934)	37–43 weeks (n=4 82 489)	Decision to include in E-NAOI
Diagnosis
Birth weight <1500 g	44.18	0.85	0.01	43.74	0.93	0.01	Included – comparable with Lain et al.8
Gestational age <32 completed weeks	51.93	N/A	N/A	N/A			Included – comparable with published incidence.15
Neonatal death within 28 days (includes deaths after 28 days if the infant was never discharged home)	5.40	0.41	0.07	7.49	0.47	0.07	Included - comparable with Lain et al and published UK incidence.3,8
Respiratory distress syndrome	55.74	8.80	0.62	49.04	7.64	0.51	Included – comparable with Lain et al.8
Seizure	0.99	0.25	0.14	1.47	0.39	0.16	Included – comparable with Lain et al and published UK incidence.8 21
Intraventricular haemorrhage (grades 3 and 4)	2.19	0.02	0.00	2.65	0.05	0.00	Included – comparable with Lain et al.8
Cerebral infarction	0.13	0.02	0.01	N/A			Included – comparable with published UK incidence.21
Periventricular leukomalacia	0.75	0.01	0.00	N/A			Included – comparable with published UK incidence.21
Birth trauma (intracranial haemorrhage paralysis due to brachial plexus injury, skull or long bone fracture)	0.25	0.09	0.07	0.33	0.08	0.09	Included – comparable with Lain et al.8
Hypoxic ischaemic encephalopathy	1.23	0.34	0.19	0.39	0.17	0.07	Included – comparable with published UK incidence.21 22
Necrotising enterocolitis	5.36	0.20	0.01	2.93	0.14	0.01	Included – comparable with Lain et al.8
Bronchopulmonary dysplasia	7.87	0.03	0.00	6.08	0.03	0.00	Excluded – a wider category capturing all chronic respiratory disease included instead.
Sepsis/septicaemia (Streptococcus Staphylococcus, Escherichia coli,unspecified Gram negative)	10.08	0.90	0.21	10.88	1.52	0.30	Included - comparable with Lain and published UK incidence.8 23
Pneumonia	2.45	0.56	0.18	2.15	0.36	0.11	Included – comparable with Lain.8
Other respiratory (primary atelectasis and respiratory failure)	2.36	0.21	0.08	N/A			Included.
Chronic respiratory disease originating in the perinatal period	13.89	0.07	0.01	N/A			Newly added diagnosis.
Bacterial meningitis	0.74	0.09	0.04	N/A			Newly added diagnosis – comparable with published UK incidence.24
Procedure
Resuscitation (intubation and/or chest compression)	14.87	1.05	0.30	21.11	1.54	0.47	Included – comparable with Lain et al.8
Ventilatory support (mechanical ventilation/CPAP/high flow nasalcannulae)	70.52	13.99	1.82	57.03	7.13	0.66	Included – higher than Lain et al but not implausible
Central venous or arterial catheter	30.62	2.45	0.35	34.12	3.83	0.34	Included – comparable with Lain et al.8
Pneumothorax requiring intercostal cathete	3.57	0.67	0.18	1.87	0.33	0.04	Included – higher than Lain et al but not implausible.
Any intravenous fluids	2.08	1.35	0.29	46.64	8.87	0.95	Included – lower than Lain et al.Suggests undercoding.
Transfusion of blood or blood products	0.47	0.11	0.02	18.08	0.86	0.10	Excluded – Much lower than Lain et al and published literature.
Any body cavity surgical procedure	7.93	1.49	0.24	4.56	1.01	0.19	Included – comparable with Lain et al.8
Therapeutic hypothermia	0.02	0.24	0.10	N/A			Newly added procedure – comparable with published UK incidence.25
Composite
Any diagnoses or procedure	84.57	20.13	3.10	81.88	18.32	2.40

^*Gestational age categories were selected to allow comparison with the figures reported by Lain et al.

CPAP, continuous positive airway pressure; E-NAOI, English-version neonatal adverse outcome indicator; HES, Hospital Episode Statistics.