Direct and indirect costs of idiopathic inflammatory myopathies in adults: A systematic review

Eden Daniel; Ian C Smith; Valentina Ly; Pierre R Bourque; Ari Breiner; Hanns Lochmuller; Nancy Maltez; Kednapa Thavorn; Jodi Warman-Chardon

doi:10.1371/journal.pone.0307144

Direct and indirect costs of idiopathic inflammatory myopathies in adults: A systematic review

PLoS One. 2024 Jul 26;19(7):e0307144. doi: 10.1371/journal.pone.0307144. eCollection 2024.

Authors

Eden Daniel^{1

2}, Ian C Smith¹, Valentina Ly³, Pierre R Bourque^{2

4}, Ari Breiner^{1

2

4}, Hanns Lochmuller^{1

2

4

5}, Nancy Maltez^{1

2

6}, Kednapa Thavorn^{1

7}, Jodi Warman-Chardon^{1

2

4

5}

Affiliations

¹ Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
² Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
³ Library, University of Ottawa, Ottawa, Ontario, Canada.
⁴ Department of Medicine, Neurology, The Ottawa Hospital, Ottawa, Ontario, Canada.
⁵ Children's Hospital of Eastern Ontario and Research Institute, Ottawa, Ontario, Canada.
⁶ Department of Medicine, Rheumatology, The Ottawa Hospital, Ottawa, Ontario, Canada.
⁷ School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada.

Abstract

Idiopathic inflammatory myopathies (IIMs) are rare disorders characterized by inflammation of skeletal muscle, which can result in fatty replacement of muscle, muscle atrophy, and subsequent weakness. Therapeutic advancements have improved clinical outcomes but impose an economic impact on healthcare systems. We aimed to summarize the direct and indirect costs associated with IIMs in a systematic review (PROSPERO Registration #CRD42023443143). Electronic databases (MEDLINE, Embase, CINAHL, and Scopus) were systematically searched for full-length articles (excluding case reports) reporting costs specific to patients diagnosed with an IIM, published between database inception and April 19, 2023. Direct cost categories included inpatient, outpatient, medication, home/long-term care, and durable medical equipment such as mobility and respiratory aids. Indirect costs included lost productivity. Eligibility criteria were met by 21 of the 3,193 unique titles identified. Costs are expressed in 2023 United States of America dollars, with adjustments for differences in purchasing power applied to currency conversions. As no study reported on all cost categories, annualized cost of IIM per patient was estimated by calculating the mean cost per category, and then adding the means of the different cost categories. By this method, IIM was estimated to cost $52,210 per patient per year. Proportional contributions by category were lost productivity (0.278), outpatient care (0.214), medications (0.171), inpatient care (0.161), home/long-term care (0.122), and durable medical equipment (0.053). Newer findings with intravenous immunoglobulin considered first line therapy for IIM demonstrated markedly higher annual medication costs per patient, upwards of $33,900 compared to an average of $3,908 ± $1,042 in older studies. Future cost-effectiveness studies require updated cost-of-illness studies reflecting the evolving sub-classification and treatment options for IIM, and should consider the impact of IIM on patients and their families.

Copyright: © 2024 Daniel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publication types

Systematic Review

MeSH terms

Adult
Cost of Illness
Health Care Costs*
Humans
Myositis* / economics
Myositis* / therapy

Grants and funding

ICS is supported by the Eric Poulin ALS Translational Research Fund. HL receives support from the Canadian Institutes of Health Research (CIHR) for Foundation Grant FDN-167281 (Precision Health for Neuromuscular Diseases), Transnational Team Grant ERT-174211 (ProDGNE) and Network Grant OR2-189333 (NMD4C), from the Canada Foundation for Innovation (CFI-JELF 38412), the Canada Research Chairs program (Canada Research Chair in Neuromuscular Genomics and Health, 950-232279), the European Commission (Grant # 101080249) and the Canada Research Coordinating Committee New Frontiers in Research Fund (NFRFG-2022-00033) for SIMPATHIC, and from the Government of Canada Canada First Research Excellence Fund (CFREF) for the Brain-Heart Interconnectome (CFREF-2022-00007). JWC is supported by a Department of Medicine University of Ottawa Clinical Research Chair and by grants from the Canadian Institutes of Health Research (INS-464765), Physician Services Incorporated (19–28), and Muscular Dystrophy Canada (932196). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.