Why do patients with myositis die? A retrospective analysis of a single-centre cohort

Clin Exp Rheumatol. Sep-Oct 2016;34(5):820-826. Epub 2016 Aug 2.

Abstract

Objectives: Causes of death in inflammatory myopathies have rarely been studied. We have assessed a cohort of myositis patients followed in a single centre over a 37-year period, reviewing the mortality rate, causes of death and predictors of poor prognosis.

Methods: We performed a single-centre, retrospective study on patients aged ≥16 years fulfilling 3 or 4 of the Bohan and Peter criteria, noting their demographic data, clinical features, serology, treatment and outcome.

Results: Of 97 patients identified, 74.2% were female. The mean age at diagnosis was 40.5 years (SD 13.2). 38.1% had adult-onset dermatomyositis, 36.1% adult-onset polymyositis and 25.8% overlap myositis. 96.9% had upper and lower limb involvement (UL+/LL+) and 62.9% had a highest CK≥10 times the upper limit of normal. 33% had significant infection(s). The disease course was chronic persistent in 29.9%, relapsing and remitting in 34% and monophasic in 36.1%. All received steroids and 92.8% other immunosuppressant(s). The median follow-up was 9 years (IQR 11.5). The estimated cumulative proportion survival at 5, 10, 15 and 20 years were 94.6%, 82.2%, 72,1% and 66.1%, respectively. 24.7% of patients died, mostly due to infection (29.2%). In univariate analysis, lung involvement (HR 1.78, p=0.013), infection (HR 4.18, p=0.003) and UL+/LL+ (HR 0.13, p=0.010) were statistically significantly associated with the risk of death. In the multivariate analysis infection (HR 3.68, p=0.009) and UL+/LL+ (HR 0.16, p=0.027) were statistically significantly associated with survival.

Conclusions: A good long-term survival is reported. Nevertheless, careful follow-up of myositis patients is important.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Cause of Death*
  • Communicable Diseases / mortality
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Lung Diseases / mortality
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Myositis / diagnosis
  • Myositis / mortality*
  • Prognosis
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk Factors
  • Time Factors
  • Young Adult