Developmental and epilepsy outcomes at age 4 years in the UKISS trial comparing hormonal treatments to vigabatrin for infantile spasms: a multi-centre randomised trial

Background Infantile spasms is the name given to a difficult to treat, severe infantile epilepsy with high morbidity. The United Kingdom Infantile Spasms Study (UKISS) showed that absence of spasms on days 13 and 14 after randomisation was more common in infants allocated hormonal treatments than vigabatrin. At 12-14 months, those with no identified aetiology allocated hormonal treatment had better development. However, epilepsy outcome was not affected by treatment allocated. It is not known if the difference in development persists as the infants grow. Methods Infants in UKISS were followed up blind to treatment allocation by telephone at a mean age of 4 years using the Vineland Adaptive Behaviour Scales (VABS) and an epilepsy questionnaire. Findings 9 of 107 enrolled infants had died. 77 were traced and consented to take part. The median (quartile) VABS scores were 60 (42, 97) for the 39 allocated hormonal treatment and 50 (36, 67) for the 38 allocated vigabatrin (Mann-Whitney U=575; p=0.091; median difference (95% CI): 8 (-1 to 19)). For those with no identified aetiology, VABS scores were 96 (52, 102) for the 21 allocated hormonal treatment and 63 (37, 92) for the 16 allocated vigabatrin (U=98.5; p=0.033; median difference (95% CI): 14 (1 to 42)). The proportions in each treatment group with epilepsy were similar. Interpretation For all 77 infants, development and epilepsy outcomes were not significantly different between the two treatment groups. The better development seen at 14 months in those with no identified aetiology allocated hormonal treatment was seen again at 4 years in this study.