Medication selection, health services outcomes, and cost trajectories for Medicaid beneficiaries with infantile spasms.

OBJECTIVE

There are three recommended first-line treatments for infantile spasms, adrenocorticotropic hormone (ACTH), oral corticosteroids, and vigabatrin, though non-standard treatments such as topiramate are sometimes selected. Is it uncertain how treatment selection influences health services outcomes.

METHODS

We conducted a retrospective cohort study of Medicaid beneficiaries newly diagnosed with infantile spasms from 2009-2010. We included infants with a new diagnosis of infantile spasms between age 2-9 months who filled ACTH (reference), prednisolone, vigabatrin, or topiramate prescriptions. Multivariable Cox proportional hazards regression compared time to first emergency department (ED) visit or hospitalization across treatment groups during 2 years of follow-up. Monthly costs for each treatment were examined in 6-month intervals and compared in a multivariable generalized linear model.

RESULTS

Among 256 children with infantile spasms, 116 received ACTH, 62 prednisolone, 15 vigabatrin, and 63 topiramate. The rate of ED visit or hospitalization per person-year did not differ significantly for prednisolone (0.9 [95 % CI 0.7-1.2]; adjusted hazard ratio [aHR] 0.84, 95 % CI 0.57-1.24), vigabatrin (0.8 [95 % CI 0.4-1.5]; aHR 0.91, 95% CI 0.45-1.84), or topiramate (1.7 [95 % CI 1.3-2.3]; aHR 1.15, 95 % CI 0.80-1.65), when compared to ACTH (1.1 [95 % CI 0.9-1.3]). The median payment for ACTH was $96,406 (interquartile range 70,742-138,476) during the first 6 months. The adjusted mean total payment in the first 6 months was 73% lower for prednisolone (95% CI -82, -61), 69% lower for vigabatrin (95% CI -84, -40), and 73% lower for topiramate (95% CI -82, -59). However, in subsequent 6-month intervals, costs associated with ACTH were not significantly different compared to other treatments.

SIGNIFICANCE

Compared to other treatments for infantile spasms, use of ACTH was associated with greater cost in the first 6 months of treatment, but not with reduced ED visits or hospitalizations. The cost effectiveness of ACTH depends on its relative clinical efficacy, and merits additional research.