Inpatient admissions and costs associated with persistent use of dalfampridine extended-release in multiple sclerosis: A claims database analysis

BACKGROUND: While the clinical benefits of dalfampridine extendedrelease (D-ER) have been established in patients with multiple sclerosis (MS) through multiple clinical trials, there is limited real-world data on D-ER use, in particular the persistent use of D-ER, and associated acute care resource utilization and costs. OBJECTIVE: To examine the real-world association of D-ER use and inpatient admissions and costs among patients with MS. METHODS: This study was a retrospective observational claims analysis of the MarketScan database (April 2009-March 2014). Eligible patients consisted of adult enrollees aged 18-64 years who had (a) 12 months of continuous private plan enrollment preceding (baseline) and following (follow-up) the first D-ER claim; (b) = 2 MS diagnosis codes with = 1 during the baseline period; (c) = 2 consecutive D-ER claims; and (d) no alternate gait-impairing etiologies during the baseline and follow-up periods. Patients were separated into 2 D-ER cohorts in the main analysis: persistent (= 360 days of D-ER supply) and nonpersistent (< 360 days of supply) users. Sensitivity analyses were conducted, examining additional breakdowns of days of supply within the nonpersistent cohort. Inpatient admissions (all-cause and MS-related) and health care expenditures were calculated and compared between the cohorts during follow-up using Wilcoxon ranksum and chi-square tests. Regression models were conducted, controlling for age, sex, MS relapses, comorbidities, disease-modifying therapy use, and other baseline factors, including inpatient admissions and costs. RESULTS: Of 1,598 eligible patients, 719 (45.0[%]) were persistent D-ER users, and 879 (55.0[%]) were nonpersistent D-ER users. The 2 cohorts had similar demographic and clinical characteristics, with mean (SD) ages of 51.0 (8.4) and 50.6 (8.6) years and were 71.3[%] and 66.6[%] female, respectively. Compared with nonpersistent D-ER use, persistent D-ER use was associated with lower odds of all-cause inpatient admissions (OR = 0.58, P = 0.010) and MS-related inpatient admissions (OR = 0.50, P = 0.004). Persistent use was also associated with lower inpatient expenditures for all-cause admissions ($669 vs. $1,515, P = 0.002) and MS-related admissions ($388 vs. $891, P = 0.008). CONCLUSIONS: Persistent D-ER use was associated with significantly lower rates of all-cause and MS-related inpatient admissions and costs.