Neuromyelitis Optica Spectrum Disorder: Clinical Burden and Cost of Relapses and Disease-Related Care in US Clinical Practice

Abstract

Introduction: Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune condition characterized by unpredictable relapses that affect the optic nerves and spinal cord, which can lead to blindness, paralysis, and increased mortality rates. Evidence on the clinical and economic burden of NMOSD in the USA is currently lacking.

Methods: A retrospective, observational cohort study was conducted using data from the IQVIA PharMetrics Plus Healthcare Claims Database between January 1, 2012 and March 31, 2019. Adults (aged 18 years or more) with evidence of NMOSD and a matched group of comparison patients were identified. Outcomes, including NMOSD relapses, healthcare utilization, and healthcare expenditure (reported in 2018 US dollars), were evaluated during the follow-up period (maximum 6 years). Healthcare utilization and expenditure were assessed overall (all-cause) and during NMOSD relapses.

Results: The study included 1363 patients with NMOSD; the mean age was 44.9 years, and 75.3% were female. During the follow-up period (median 2.0 years), 47.7% of patients with NMOSD had one or more relapses, corresponding to an annualized relapse rate of 0.8 (95% confidence interval [CI] 0.7-0.9). When analyzing healthcare expenditure per patient, the mean annualized all-cause healthcare expenditure among patients with NMOSD was $60,599 (95% CI $52,112-66,716) compared with $8912 (95% CI $7084-10,727) among comparison patients, representing a difference of $51,687 (95% CI $43,820-58,664) attributable to NMOSD. The mean annualized total expenditure for NMOSD relapses was $10,070 (95% CI $7726-12,660) per patient, with hospital/inpatient care requiring more expenditure than ambulatory/outpatient care.

Conclusion: Findings of this large, retrospective, observational study indicate that relapses among patients with NMOSD are common in US clinical practice, leading to substantial healthcare utilization and expenditure. Therapies with the highest relapse risk reduction could lead to markedly lower relapse-associated healthcare utilization and clinical burden in patients with NMOSD.

Keywords: Cost of illness; Disease burden; Economic burden; Healthcare costs; Healthcare resource utilization; Neuromyelitis optica; Neuromyelitis optica spectrum disorder; Optic neuritis; Relapses; Transverse myelitis.

Fig. 1

Identification of patients with NMOSD and matched comparison patients. ^aFor patients with at least one diagnosis code for NMO in the acute care hospital/inpatient setting, the index date was defined as the date of the first hospitalization. For patients with at least two diagnosis codes for NMO in the ambulatory/outpatient setting, the index date was defined as the date of the second qualifying encounter. For comparison patients, the index date was defined by the index date of the matched patient with NMOSD. ^bComparison patients were matched on the basis of age, sex, geographic region, and health plan type. MS, multiple sclerosis; NMO, neuromyelitis optica; NMOSD, neuromyelitis optica spectrum disorder

Fig. 2

Distribution of patients with NMOSD stratified by annualized number of a relapses and b relapse days. NMOSD, neuromyelitis optica spectrum disorder

Fig. 3

Distribution of patients with NMOSD by annualized healthcare expenditure. a Proportion of patients stratified by annualized healthcare expenditure. b Annualized mean healthcare expenditure by annualized number of relapses. ^aIncludes the 52.2% of patients who had no evidence of a relapse, plus 40 patients who had evidence of relapses with no associated costs. ^bReported in 2018 US dollars. NMOSD, neuromyelitis optica spectrum disorder