Long-Term Survival of Patients With Idiopathic Inflammatory Myopathies According to Clinical Features

Abstract

The idiopathic inflammatory myopathies are characterized by chronic muscle inflammation and involvement of internal organs, which contribute considerably to the morbidity and mortality of the disease. We conducted the current study to determine the survival data for patients with idiopathic inflammatory myopathies according to the presence of extramuscular clinical manifestations. We also determined the cumulative survival probability and the long-term prognosis and analyzed the causes of death at a single clinical immunology center.A survival analysis was performed using data for 162 patients diagnosed between 1976 and 1997 according to Bohan and Peter's criteria. Patients were followed up for a minimum of 5 years (median, 101.5 mo) or to date of death. Cumulative survival probability was calculated by the Kaplan-Meier method. The influence of extraskeletal and extramuscular involvement was analyzed as prognostic factors for death by Cox proportional hazards survival model. Eighteen disease-specific deaths occurred; pulmonary and cardiac complications were the most frequent causes of death. Global survival rates were 95%, 92%, and 89% for 1, 5, and 10 years, respectively. Analysis for clinicopathologic subgroups revealed that cancer-associated myositis had the worst prognosis, while juvenile and overlap myositis had the best prognosis. Five- and 10-year survival rates were 94.2% and 89.4% for patients with primary polymyositis and 90.1% and 86.4% for primary dermatomyositis patients, respectively. In the whole group of patients with idiopathic inflammatory myopathy, cardiac (p < 0.01) and respiratory muscle involvement (p = 0.045) were significant prognostic factors for death. In the group of patients with primary polymyositis/dermatomyositis, cardiac involvement was the main prognostic factor for death (p < 0.01). Myositis patients described in this study have higher survival rates than reported previously worldwide. We examine the reasons for the differences between the data in the current study and the available survival data in the relevant literature.

Cardiac Involvement in Adult Polymyositis or Dermatomyositis: A Systematic Review

“…4,6,9 Because clinical manifestations of heart diseases are relatively infrequent, clinicians have not paid much attention to it. This review suggests that heart failure is the most common clinical symptom.…”

“…6 Cancer, lung, and cardiovascular complications are generally cited as the most common causes of death in PM/DM patients. In the articles included, 37 patients (46.3%) died as a direct result of heart disease.…”

“…Among those deaths, arrhythmia, heart failure, cardiac arrest, and myocardial infarction were most commonly referred to. Moreover, the study by Danko et al 6 showed that cardiovascular complications caused death mainly after a 5-year disease duration.…”

Opportunistic infections in polymyositis and dermatomyositis

“…Polymyositis (PM) and dermatomyositis (DM) are systemic inflammatory disorders affecting skeletal muscles and other organs (1)(2)(3)(4)(5). PM and DM are considered to be associated with high morbidity and mortality rates, in some cases as high as 50%, primarily related to life-threatening muscle weakness, cardiac and lung impairment, as well as infectious manifestations (1)(2)(3)(4)(5).…”

“…PM and DM are considered to be associated with high morbidity and mortality rates, in some cases as high as 50%, primarily related to life-threatening muscle weakness, cardiac and lung impairment, as well as infectious manifestations (1)(2)(3)(4)(5). In clinical series of patients with PM/DM, infectious complications have been described in up to 26% of patients (1,2,4,6). Several factors may be implicated in this apparent increased frequency of infections in PM/DM patients, particularly immunosuppressive medications.…”