Cost of illness in multiple sclerosis by disease characteristics – A review of reviews

ABSTRACT

Introduction

In light of the increasing number of economic burden studies and heterogeneity in methodology and reporting standards, there is a need for robust evidence synthesis on an umbrella review level.

Areas covered

We performed the first review of reviews of cost-of-illness studies in multiple sclerosis. Focusing on disaggregated costs by disease characteristics (disability level, relapse, disease course), we also characterized the underlying methodological evidence base of individual (primary) studies.

Expert Commentary

We identified 17 reviews encompassing 111 unique primary studies, and a high degree of overlap across reviews. Costs were substantial, rising with disability level, relapse episodes, and disease progression. Disability was the key cost driver. Compared to mild disability, total costs for moderate disability were 1.4–2.3-fold higher and 1.8–2.9-fold higher for severe disability. With escalating disability, the share of costs outside the health system (indirect costs, informal care) increasingly outweighed the share of direct medical costs. Of all 111 primary studies, 72% gathered resource use/loss data by patient self-report. Associated costs were mostly reported by disability level (75%), followed by relapse (48%) and disease course (21%). In conclusion, although heterogeneity can make in-depth comparisons of costs across studies impossible, important patterns are broadly apparent.

KEYWORDS:

• Resource utilization
• cost burden
• cost of illness
• cost-of-illness
• systematic review
• overview
• meta-review
• umbrella review
• economics
• multiple sclerosis

Article highlights

• Seventeen reviews of varying methodological quality and a high degree of overlap between reviews were identified, with 111 unique primary studies included across all reviews.

• Methods and results from cost of illness studies were characterized by a high amount of heterogeneity, which was additionally promoted by the lack of universally agreed methodological and reporting standards.

• The level of disability, disease progression, and relapse occurrence were associated with significant costs for patients, informal caregivers, the healthcare system and society.

• Unlike costs by level of disability and disease course, no review primarily aimed to synthesize relapse costs systematically.

• As disability escalates, the impact of MS increasingly went beyond costs to the health care system (direct medical costs), primarily through lost productivity (indirect costs) and the need for informal care (direct nonmedical costs, or indirect costs).

• Stratifying cost estimates by level of disability was the reference standard for reporting costs, particularly in non-representative samples

• The majority of the 111 primary studies were conducted in Europe or North America, with costs mostly considered from a societal perspective and based on patient-reported resource use/loss data.

• There was a lack of publicly available resource use/loss questionnaires and a lack of psychometric validation

Data availability statement

All relevant data and references are within the paper and its supporting appendix. Further inquiries can be directed to the corresponding author.

Declaration of Interests

T Ziemssen has received consulting and/or speaking fees from Almirall, Bayer, Biogen, Merck, Novartis, Roche, Sanofi, and Teva; and grant/research support from Biogen, Novartis, Sanofi, and Teva. R Haase has received travel grants from Celgene and Sanofi. NH Ness has received research support from Novartis and is an employee of Hexal AG, Holzkirchen, Germany. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14737167.2022.1987218

Additional information

Funding

This paper is not funded.