Interstitial lung disease status at baseline critical prognostic factor in polymyositis, dermatomyositis
Among patients with polymyositis or dermatomyositis, the progression of interstitial lung disease is the most important factor in survival, with respiratory infection as an additional predictor, according to findings published in Arthritis Research and Therapy.
“Polymyositis and dermatomyositis are idiopathic inflammatory myopathies of unknown causes, which are often associated with extramuscular manifestations such as interstitial lung disease, arthropathy, cardiomyopathy and malignancies,” Yumiko Sugiyama, of the department of stem cell and immune regulation at the Yokohama City University Graduate School of Medicine, in Japan, and colleagues wrote. “[Polymyositis-dermatomyositis]-associated [interstitial lung disease] is a major cause of death, with an estimated excess mortality rate of around 40%, and has a widely varied clinical course.”
To determine the predictors for death and serious infection among individuals with polymyositis/dermatomyositis-associated interstitial lung disease, the researchers conducted a retrospective review of 116 patients across six hospitals from 2003 to 2016. Researchers retrieved patient data from medical charts and analyzed demographic, clinical and laboratory information at baseline, as well as treatment regimens and outcomes.
In addition, the researchers studied lesion distribution among patients with interstitial lung disease, using high-resolution, computer-generated images to split the lung into four different zones.
According to the researchers, 14 of the 116 patients died within 6 months of diagnosis. Independent risk factors for death included extended lesions related to interstitial lung disease in the upper lung zones (OR = 8.01; P = .016), and hypocapnia (OR = 6.85; P = .038). In addition, the researchers discovered serious infections in 38 of the patients, including 11 of those who died of respiratory or other infections. Independent risk factors for these deaths included high serum KL-6 (OR = 3.68; P = .027), a high initial dose of prednisolone (OR = 4.18; P = .013) and combination immunosuppressive therapies (OR = 5.51; P < .001).
“This study showed that presence of the [interstitial lung disease] lesion in the upper lung fields and hypocapnia were independently associated with unfavorable clinical outcomes, especially early death in patients with [polymyositis-dermatomyositis-associated interstitial lung disease],” Sugiyama and colleagues wrote. “We found both local and extrapulmonary findings, including immunosuppressive therapies, were risk factors for fatal events and serious infections in patients with [polymyositis-dermatomyositis-associated interstitial lung disease], based on clinical findings.” – by Jason Laday
Disclosure: The researchers report grant funding from Bristol-Myers K.K. (RY).