No Improvement in Mortality Rate for Idiopathic Inflammatory Myositis

The medical field has seen many advancements over the past few decades. In particular, treatment for rheumatic diseases has greatly improved. However, states Healio, this is not reflected in patient outcomes for those with idiopathic inflammatory myositis. In fact, data presented at the EULAR 2020 E-Congress suggests that early mortality rates related to the condition have remained relatively unchanged.

Idiopathic Inflammatory Myositis

Although doctors aren’t quite sure of myositis’ cause, many believe it shares characteristics of an autoimmune disorder. In these disorders, the immune system mistakenly attacks the body, causing pain, damage, and inflammation. To understand what idiopathic inflammatory myositis is and does, let’s break down the terms:

  • Idiopathic: any condition that happens spontaneously or without a known cause.
  • Inflammatory: causing inflammation and swelling.
  • Myositis: inflammation or swelling of the muscles.

So, idiopathic inflammatory myositis occurs when someone experiences chronic muscle inflammation with no specific cause. There are a number of different subsets, including necrotizing myopathy, polymyositis, and dermatomyositis.

Symptoms include:

  • A distinctive rash (dermatomyositis)
  • Difficulty lifting arms, standing up from a chair, or climbing stairs
  • Joint and muscle pain
  • Difficulty swallowing or breathing
  • Shortness of breath
  • Fatigue after standing or walking
  • Raynaud’s syndrome

Learn more about idiopathic inflammatory myositis.

Mortality Rates

According to Dr. Kristin M. D’Silva, MD, the exact mortality rate associated with idiopathic inflammatory myositis isn’t clear. Past estimates differ widely, from 23% up to 73%. So, alongside her team, D’Silva sought to understand whether early (premature) mortality rates improved – or sit on par with the mortality rates of other rheumatic diseases.

Patient data included:

  • Average age: 58 years old
  • Sex Breakdown: 62% female; 38% male
  • Early cohort: 355 patients diagnosed with dermatomyositis or polymyositis over a 7 year period. 3,182 matched controls based on age, sex, birth year, and database entry year.
    • 57.4 deaths/1000 person-years (patients with myositis) vs. 15.2 deaths/1000 person-years (controls)
  • Late cohort: 369 patients who received their diagnoses over a 7 year period. 3,551 controls.
    • 43.2 deaths/1000 person-years (patients with myositis) vs. 14.1 deaths/1000 person-years (controls)

Additionally, patients with idiopathic inflammatory myositis were still seen to have higher mortality rates than controls even when taking age, sex, alcohol and drug use, cigarette smoking, doctor visits, medication, and comorbidities into account.

As a result, the study determined that patients with idiopathic inflammatory myositis are 2.5x more likely to experience early mortality than others. Thus, research should examine why this is true moving forward.


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