Evaluation of inpatient and emergency department healthcare resource utilization and costs pre- and post-nusinersen for the treatment of spinal muscular atrophy using United States claims

Abstract

Aim: Nusinersen, administered by intrathecal injection at a dose of 12 mg, is indicated across all ages for the treatment of spinal muscular atrophy (SMA). Evidence on real-world healthcare resource use (HRU) and costs among patients taking nusinersen remains limited. This study aimed to evaluate real-world HRU and costs associated with nusinersen use through US claims databases. Patients & methods: Using the Merative™ MarketScan^® Research Databases, patients with SMA receiving nusinersen were identified from commercial (January 2017 to June 2020) and Medicaid claims (January 2017 to December 2019). Those likely to have complete information on the date of nusinersen initiation and continuous enrollment 12 months pre- and post-index (first record of nusinersen treatment) were retained. Number and costs (US$ 2020) of inpatient admissions and emergency department (ED) visits, unrelated to nusinersen administration, were evaluated for 12 months pre- and post-nusinersen initiation and stratified by age: pediatric (<18 years) and adult (≥18 years). Results: Overall, 103 individuals treated with nusinersen were retained: 59 were pediatric (mean age [range]: 9 [1-17] years), and 44 were adults (30 [18-63] years). Inpatient admissions decreased by 41% for pediatrics and 67% for adults in the 12 months post-treatment versus the 12 months pre-treatment. Average inpatient admission costs per patient for the pediatric cohort decreased by 63% ($22,903 vs $8466) and by 79% ($13,997 vs $2899) for the adult cohort when comparing the 12 months pre-index with the 12 months post-index period. Total ED visits and ED visit costs decreased by 8% and 35%, respectively, for the overall cohort over the 12-month period pre- and post-index. Conclusion: Using US claims databases, nusinersen treatment in pediatric and adult patients was associated with reductions in HRU and costs over a 12-month period post-treatment initiation relative to the pre-treatment period.

Keywords: commercial and Medicaid claims; healthcare resource utilization; medical cost offsets; nusinersen; patient-level claims; spinal muscular atrophy.

Figure 1.. Study design and patient selection using Merative MarketScan^® data.

(A) Study design. (B) Patient selection. The retrospective study started on 1 January 2016 to allow for the analysis of 12-month pre-treatment period before nusinersen was approved on 23 December 2016. The index date is the first date of nusinersen treatment. *Patients who received any of the first four recorded nusinersen doses in intervals of 120 days or greater (which would indicate maintenance doses and not loading doses per US label) were excluded. Patients with ≤4 doses were retained, as long as the inter-dose intervals for each of the first four recorded doses were within 120 days, respectively. ICD-10: International Classification of Diseases, 10th Revision; SMA: Spinal muscular atrophy.

Figure 2.. Total number of inpatient admissions and days spent in hospital in individuals with SMA in the 12 months before and after nusinersen treatment.

(A) Inpatient admissions. (B) Days spent in inpatient admissions. SMA: Spinal muscular atrophy.

Figure 3.. Total and average costs of inpatient admissions in individuals with spinal muscular atrophy in the 12 months before and after nusinersen treatment.

(A) *Total costs. (B) **Average costs. *No SDs were available for total costs. Total overall costs shown at end of bars were reflective of services charged through hospital stay; respiratory-related referred to pneumonia, ventilation support and other respiratory illness, symptom or insufficiency. **Cost values presented at the end of the bars represent average overall costs. SD: Standard deviation; SMA: Spinal muscular atrophy.

Figure 4.. Total number of ED visits (A) and costs (B) in individuals with SMA in the 12 months before and after nusinersen treatment.

ED: Emergency department; SMA: Spinal muscular atrophy.