Table 4. Indirect costs of IIM reported per annum.

Study (Country of Study)	IIM Subtype(s)	Disability	Absenteeism	Other
Bradford Rice et al.2016 (USA) [26]	DM/PM	6.8 Days $1,526†	10.7 days $2,401†
Christopher-Stine et al. 2020 (USA) [28]	DM/PM		9%* $5,250†	Presenteeism = 22%* ($12,834†) Work Productivity Loss = 28%* ($16,334†) Non-work Activity Impairment = 40%
Leclair et al. 2021 (Sweden) [9]	DM/PM/IBM	29.0 days $4,056	47.8 days $4,791

Costs have been converted to 2023 USD with adjustments for purchasing power parity.

*Cost provided as a percentage of work time

^†Calculated within this review based on 260 working days per year and median weekly earnings of $1,118 ($58,335 per year) [47].

DM: Dermatomyositis, IBM: Inclusion Body Myositis, IIM: Idiopathic Inflammatory Myopathies, PM: Polymyositis