Optimal lead time for treatment of infantile epileptic spasms syndrome-a secondary data analysis.

Background: Infantile epileptic spasms syndrome (IESS) is a common epileptic syndrome in infancy. Current first-line treatments include adrenocorticotropic hormone (ACTH), corticosteroids and vigabatrin, with early control of epileptic spasms potentially benefiting long-term outcomes, such as improved psychomotor development. Early treatment, which means the prompt use of first-line treatments, is crucial for achieving an initial response in IESS. However, to date, no clear definition of the specific timeframe that constitutes early treatment has been identified. The objective of this study is to perform a secondary analysis of our previously published IESS cohort data to determine a suitable lead time.

Methods: An analysis was conducted using a cohort of 263 children with IESS who had previously received ACTH first-line treatment. This study investigated whether intervening within a certain treatment time window could potentially increase or decrease the likelihood of a short-term response.

Results: Out of the 263 children with IESS, 108 achieved a short-term response. The lead time of the response group was significantly shorter than that of the non-response group [1.50 (interquartile range, 1.00, 3.00) 2.00 (interquartile range, 1.00, 5.00) months; P=0.003]. A restricted cubic spline graph with several adjusted variables, including time of first spasm and aetiological classification, showed a significant linear relationship between lead time and short-term response and a non-linear trend (inverted U-shaped curve), with a significant inflection point at 1.6 months. Using 1.5 months as the cutoff and dichotomising lead time, the adjusted logistic regression results showed that in children with a lead time >1.5 months, the likelihood of a short-term response decreased with increasing lead time [odds ratio (OR) =0.59, 95% confidence interval (CI): 0.33-0.92, P=0.041), whereas children with a lead time ≤1.5 months showed no significant association between lead time and short-term response (OR =1.03, 95% CI: 0.72-1.47, P=0.89).

Conclusions: For children with IESS, initiating first-line treatment within 1.5 months of the onset of spasms is recommended. For those who start first-line treatment after more than 1.5 months from the onset, the likelihood of a short-term response may significantly decrease as the lead time increases.