Abstracts

Rationale: Infantile spasms is a rare form of epileptic encephalopathy presenting in the first 2 years of life with the peak age of onset between 3 and 7 months. This study aimed to estimate the incidence and putative risk factors of infantile spasms, and to measure the occurrence of neurocognitive outcomes following infantile spasms. Methods: We performed a retrospective observational study over 6 years (Jan 1, 2009-Dec 31, 2014), using U.S. nationwide commercial claims data from Truven MarketScan® database. Subjects who were born in 2009 and 2010 were analyzed. Infantile spasms were defined using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes as an occurrence of =1 ICD-9-CM diagnosis codes 345.6, 345.60 or 345.61. We measured 8 categories of putative risk factors and 10 neurocognitive comorbidities, including 3 categories of intellectual disabilities, behavioral disorders, and headache. Results: Out of 984708 newborns (male=506306), 529 infantile spasms cases were identified (5 per 10000 live births). Diagnostic tests was performed as EEG (470, 88.8%), brain Imaging with ultrasound, CT or MRI (398, 75.2%), and genetic tests such as chromosomal microarray and epilepsy gene panel (6, 1.1%). Out of 529 subjects, 220 (41.6%) had no putative risk factors and 309 (58.4%) had =1 putative risk factors: perinatal morbidity (175, 33.1%), congenital anomalies (120, 22.7%), brain malformation (105, 19.8%), stroke or cerebrovascular disease (74, 13.8%), hydrocephalus (53, 10%), tuberous sclerosis (29, 5.5%), central nervous system infection (18, 3.4%), and congenital infection (2, 0.4%). During follow-up, 320 subjects (60.5%) had =1 intellectual disabilities such as delayed milestones, specific delays in development, mental retardation, and problem with learning, and 27 (5.1%) had autism. Out of 529 subjects, 189 (35.7%) received standard treatment such as ACTH (114, 21.6%), oral corticosteroids (79), and vigabatrin (79), while 215 received other antiepileptic drugs including topiramate (128, 24.2%), clonazepam (88), phenobarbital (87), valproate (45), zonisamide (44), and clobazam (34). Conclusions: The incidence of infantile spams in this cohort is compatible to one from prior traditional epidemiology studies. Perinatal morbidity, congenital anomalies, brain malformation, and stroke or cerebrovascular disease were common putative risk factors in order. More than half of patient with infantile spasms had comorbid conditions of intellectual disabilities. Funding: Children’s Healthcare of Atlanta research grant funded by the Goizueta Foundation.