Background: For patients with multiple sclerosis (MS), previous research identified key disease sequelae as important cost drivers and suggested that among users of disease-modifying drugs (DMDs) in 2004, DMDs represented 73% of the total cost of care. More recent studies were limited to incident disease/treatment and/or excluded DMDs from cost estimates. To support contemporary pharmacoeconomic analyses, the present study was conducted to provide updated information about MS-related costs and cost drivers including DMDs.
Methods: For each of 2 years, 2006 and 2011, commercially insured, continuously eligible patients with ≥ 1 medical claim diagnosis of MS were sampled. MS-related charges were based on medical claims with MS diagnosis plus medical/pharmacy claims for DMDs. 2006 charges were adjusted to 2011 $ using the medical care component of the consumer price index (CPI). Subgroups of patients using DMDs (interferon [IFN] beta-1a intramuscular or subcutaneous, IFN beta-1b, glatiramer, natalizumab) in 2011 were identified. By-group differences were tested with bivariate statistics.
Results: Mean (standard deviation [SD]) age of 15,902 sample patients in 2011 was 47.6 (11.8) years, 76% female. Mean [SD] MS charges ($26,520 [$38,478] overall) were significantly (P < 0.001) higher for patients with common disease sequelae: malaise/fatigue (n = 2,235; $39,948 [$48,435]), paresthesia (n = 1,566; $33,648 [$45,273]), depression (n = 1,255; $42,831 [$51,693]), and abnormality of gait (n = 1,196; $48,361 [$55,472]). From 2006 to 2011, CPI-adjusted MS charges increased by 60%. Among patients treated with a single DMD in 2011, inpatient care was 6% of charges (range = 4%-8%; P = 0.155); outpatient care was 19% (range = 14%-20% except for natalizumab [29%]; P < 0.001); and DMDs were 75% (range = 67%-81%; P < 0.001).
Conclusions: Common MS sequelae remain important cost drivers. Although MS treatment costs are increasing, the proportion of MS charges due to DMDs in 2011 is similar to that reported in 2004.