Table 1. Characteristics of included studies.
| Study | Original Currency | Country and Period of Study | IIMSubtype(s) | Study Population (n, % Female, mean age) |
Study Design | Data Source |
|---|---|---|---|---|---|---|
| Bamrungsawad et al. 2015 [40] | USD 2012† | Thailand 2012* |
DM | Hypothetical cohort (i.e., simulated data) 40+ years |
Cost-utility analysis using a Markov model to estimate costs | National Health Security Office, Drugs and Medical Supplies Info Centre, Hospital Database, 2 Neurologists and a Health Economist |
| Bernatsky et al. 2011 [39] | CAD 2008 | Canada 1989–2003 |
DM/PM | n = 1102 68.9% Female 57.4±18.4 years |
Retrospective database analysis of direct costs | Physician billing and hospitalization databases of Quebec |
| Bradford Rice et al. 2016 [26] | USD 2013 | USA 1998–2014 |
DM/PM | n = 2617 64.6% Female 49.5±10.5 years |
Retrospective database analysis of direct and indirect costs | Administrative claims from OptumHealth Reporting and Insights |
| Capkun et al. 2017 [27] | USD 2016* | USA 2009–2013 |
IBM | n = 333 34% Female 69±9.6 years |
Retrospective database analysis of direct costs | Truven Health MarketScan Commercial Claims and Encounters and Medicare Supplemental Research database |
| Christopher-Stine et al. 2020 [28] | N/A | USA 2017 |
DM/PM | n = 524 78.1% Female 55.4±12.9 years |
Cross-sectional survey of indirect costs and unplanned medical encounters | Patient surveys via The Myositis Association and John Hopkins Myositis Center |
| Foocharoen et al. 2013 [41] | USD 2010*‡ |
Thailand 2010 |
DM/PM | n = 269 61.7% Female 50.4±13.7 years |
Cross-sectional study of hospitalization rates and direct costs | National pooled database of hospitalized patients |
| Foreman et al. 2017 [43] | AUD 2016* | Australia 2000–2014 |
DM/PM/IBM | n = 57 70% Female 58 (24–87) years |
Retrospective case-note review of IVIg costs | Case-notes from physician assessments in South Australia |
| Furst et al. 2012 [29] | USD 2009 | USA 2003–2008 |
DM/PM/Interstitial Myositis | n = 4,487 66.0% Female 55% were 45–64 years |
Retrospective database analysis to assess resource utilization longitudinally in insured patients | Managed Care Organization database affiliated with OptumInsight |
| Keshishian et al. 2018 [4] | USD 2014 | USA 2009–2013 |
IBM | n = 361 47.6% Female 75.8±6.3 years |
Retrospective database analysis of direct costs | National Medicare database |
| Knight et al. 2017 [30] | USD 2015* | USA 2009–2014 |
DM/PM | n = 1,967 68.9% Female 48.5 years |
Retrospective observational database study comparing non-medication costs | Commercial health insurance administrative claims databases |
| Kundrick et al. 2019 [31] | USD 2016 | USA 2005–2014 |
DM | n = 6.3 x106 scans** 72.6% Female 0–64 years |
Retrospective comparison of costs of different modalities for pulmonary and malignancy screening. | MarketScan Commercial Claims and Encounters Database |
| Kwa et al. 2017 [32] | USD 2014 | USA 2002–2012 |
DM | n = 11,092 hospitalizations 71.6% Female 58.1 years |
Retrospective database analysis examining inpatient cost of care | National Inpatient Sample from Agency for Healthcare Research and Quality |
| Leclair et al. 2021 [9] | EUR 2019 | Sweden 2010–2016 |
DM/PM/IBM | n = 673 61% Female 60±16 years |
Population-based longitudinal cohort study estimating annual direct and indirect costs 5 years pre- and post-diagnosis | Swedish National Patient Register |
| Miyazaki et al. 2021 [42] | JPY 2019* | Japan 2009–2019 |
DM/PM | n = 836 60.4% Female 46.9±15 years |
Retrospective longitudinal examination of healthcare costs in the three years following diagnosis | Health insurance claims data retrieved from Japan Medical Data Center database |
| Ren et al. 2019 [33] | USD 2009 | USA 2002–2012 |
DM | n = 58,587 admissions 73.7% Female 57.4 years |
Retrospective examination of inpatient costs with/without serious infection | National Inpatient Sample from Agency for Healthcare Research and Quality |
| Rosas et al. 2021 [34] | USD 2020* | USA 2005–2014 |
DM/PM | n = 545 74.9% Female Median ~70 years |
Retrospective examination of cost of total hip arthroplasty | National database of surgeries and outcomes |
| Rose et al. 2015 [44] | GBP 2015* | International 1993–2014 |
IBM | Not Applicable | Cochrane review assessing the effectiveness of treatments | Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register for Controlled Trials, MEDLINE, and EMBASE |
| Schweitzer & Fort 1995 [35] | USD 1994* | USA 1993–1994* |
PM | n = 25 28–55 years |
Single centre prospective study assessing cost effectiveness of MRI-guided muscle biopsy | Hospital accounting system |
| Tripathi & Fernandez 2021 [36] | USD 2015 | USA 2009–2015 |
DM | n = 39,253 hospitalizations 73% Female 63% were 40–79 years |
Retrospective analysis of inpatient costs with and without malignancies | National Inpatient Sample from Agency for Healthcare Research and Quality |
| Ungprasert et al. 2020 [37] | USD 2014 | USA 2005–2014 |
DM/PM | n = 160,528 admissions 68.7% Female 58.0 years |
Retrospective database analysis examining inpatient costs and resource utilization | National Inpatient Sample from Agency for Healthcare Research and Quality |
| Zhang et al. 2019 [38] | USD 2014 | USA 2010–2014 |
DM | n = 2016 same-cause readmissions | Retrospective examination of hospitalization and readmission rates and associated costs | Nationwide Readmissions Database |
* Year not explicitly reported; year is assumed.
†Costs converted back to Thai baht (31.08 per $1 USD) [40].
‡ Costs converted back to Thai baht (31.69 per $1 USD) [23].
DM: Dermatomyositis, IBM: Inclusion Body Myositis, IIM: Idiopathic Inflammatory Myopathies, IVIg: Intravenous Immunoglobulin, MRI: Magnetic Resonance Imaging, PM: Polymyositis