Background/Purpose: Dermatomyositis and polymyositis (DM/PM) are inflammatory myopathies that can lead to persistent muscle weakness and disability. Although significant healthcare resource utilization (HCRU) and work loss among DM/PM patients have been reported, the economic burden to the national population has not been explored. The aim of this study was to provide a contemporary estimate of the total and incremental direct medical cost burden of DM/PM in the US. Total and incremental indirect work-loss burden attributable to DM/PM were also analyzed.

Methods: Patients aged 18-64 years with a first diagnosis of DM/PM between 1/1/1998 and 3/31/2014 were selected from a large, de-identified, privately-insured administrative claims database (OptumHealth Reporting and Insights). Propensity score (1:1) matching of DM/PM patients with non-DM/PM controls from the same database was performed to reduce baseline differences in demographic characteristics, comorbidities, HCRU, and costs. Healthcare costs (inpatient, outpatient/physician office, emergency department, other, pharmacy) and indirect work loss (disability days, medically-related absenteeism) were compared between matched DM/PM patients and controls from the payer perspective over 12 months post-diagnosis. The prevalence of DM/PM in the US was estimated from the recent literature.

Results: A total of 2,587 DM/PM patients who met the sample selection criteria were matched with a control. Overall, commercial payers incurred $23,064 in total healthcare costs per DM/PM patient during the 12-month outcome period. Relative to controls, DM/PM patients had, on average, $7,368 (47%) higher total healthcare costs ($23,064 vs. $15,695; p<0.001). Paired with US population statistics and estimates of DM/PM prevalence (ranging from 14.8 to 19.5 DM/PM cases per 100,000 persons), results of this analysis suggest that DM/PM patients impose a total direct medical cost burden of approximately $457 to $602 million (in 2013$) to commercial payers, or approximately $146 to $192 million in excess costs over matched controls. Further, work loss among DM/PM patients amounted to $3,621 in annual costs, $633 (21%) more than the non-DM/PM patients ($3,621 vs. $2,988; p<0.001).These results suggest that DM/PM patients impose an indirect cost burden of approximately $76 to $100 million to employers in work-loss costs, or approximately $13 to $17 million in excess work-loss costs compared with matched controls. The estimated total costs (direct and indirect) of DM/PM range from $533 to $702 million a year.

Conclusion: DM/PM is associated with substantial economic burden in the US population due to significantly increased healthcare costs and work loss. Moreover, results of this analysis potentially underestimate the excess burden of DM/PM because a few high-cost DM/PM patients could not be matched. Also, the actual national cost of DM/PM is likely understated as this study excluded individuals 65 years and older, out-of-pocket costs, supplemental insurer payments, and informal caregiving. Finally, only costs in the 12 months following diagnosis were assessed; costs may increase due to changes in disease severity over time.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-economic-burden-of-dermatomyositis-and-polymyositis-in-the-us/