Incidence, Prevalence, and Mortality of Dermatomyositis: A Population‐Based Cohort Study

Abstract

Objective. We aimed to determine the population-based incidence, prevalence, and mortality of dermatomyositis (DM) using European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) criteria.Methods. This population-based cohort study included incident DM from January 1, 1995 to December 31, 2019. We manually reviewed all individuals with at least 1 code for DM or polymyositis to determine if they met EULAR/ ACR criteria, subspecialty physician diagnosis, and/or Bohan and Peter criteria. We age-and sex-adjusted incidence and prevalence estimates to the US non-Hispanic White year 2000 population and estimated prevalence on January 1, 2015. Standardized mortality ratios (SMRs) with 95% confidence intervals (95% CIs) compared observed to expected mortality adjusting for age, sex, and year.Results. We identified 40 cases of verified DM, with 29 cases incident in Olmsted County from 1995 to 2019. The mean age was 57 years, 26 (90%) were female, and 12 (41%) had clinically amyopathic DM (CADM). The median follow-up time was 8.2 years. The overall adjusted incidence of DM was 1.1 (95% CI 0.7-1.5) per 100,000 person-years, and prevalence was 13 (95% CI 6-19) per 100,000. The SMR was significantly elevated among the myopathic DM cases (3.1 [95% CI 1.1-6.8]) but not CADM cases (1.1 [95% CI 0.2-3.3]). The positive predictive value of ≥2 DM codes was only 40 of 82 (49%).Conclusion. This population-based study found that DM incidence and prevalence were higher than previously reported. Mortality was significantly elevated for myopathic DM but not for CADM.The content herein is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

New-onset dermatomyositis following SARS-CoV-2 infection and vaccination: a case-based review

“…Dermatomyositis is a rare disease with an incidence of 1 to 15 per million [ 1 ]. Apart from muscle and skin, the disease can also affect other organs, such as lungs, heart, and blood vessels with varying clinical outcomes, depending on the specific antibody [ 2 ].…”

Incidence of Dermatomyositis in a Nationwide Cohort Study of US Veterans

“…Of the few available studies, most demonstrate a stable incidence of DM, with the exception of a small cohort study from Olmsted County, Minnesota . A more recent study from Olmsted County demonstrated no change in incidence from 2009 to 2017 compared with the period from 1995 to 2007 . There are more studies evaluating idiopathic inflammatory myopathies as a whole or evaluating polymyositis plus DM .…”

“…The use of ICD-9 or ICD-10 coding to identify patients with DM has its limitations. Kronzer et al reported a positive predictive value of 49% for 2 DM ICD-9 or ICD-10 codes when using EULAR/ACR (European Alliance of Associations for Rheumatology/American College of Rheumatology) 2017 diagnostic criteria. This suggests that ICD-9 and ICD-10 coding alone is not precise in identifying DM cases.…”

Dermatomyositis in Association With SARS‐CoV‐2 Infection or COVID‐19 Vaccine

“…This group also includes polymyositis, inclusion body myositis, and immune‐mediated necrotizing myopathy 1,2 . DM is characterized by proximal muscle weakness, skin involvement, and an increased risk of developing interstitial lung disease 3,4 . Gottron's papules, skin ulceration, mechanic hands, and heliotrope eruption are characteristic skin lesions in patients with DM 5,6 .…”