Myositis - It Can Take Your Breath Away

Myositis is truly a multi-systemic disease. Along with muscle and skin, internal organs such as the lungs can be affected. This is especially prevalent in patients with anti-synthetase syndrome, where interstitial lung disease (ILD) can be a prominent feature.

Myositis-associated ILD (MA-ILD) may be a major contributor to mortality. However, information from clinical trials to guide treatment and response to treatment is lacking due to a paucityof validated outcome measures. A standard approach is to follow serial pulmonary function tests (PFTs) in a myositis patient with ILD. However, the degree of change in these measures that actually correlates with survival has not been studied.

Dr. Rohit Aggarwal and his team from the University ofPittsburgh Medical Center aimed to investigate PFT variable changes over 1 year as predictors of outcome in patients with MA-ILD (poster abstract #294). They utilized their prospective myositis patient database that includes patients enrolled between 1985-2014, who fulfilled the myositis definition of definite or probable myositis according to Bohan and Peter, or who presented with anti-synthetase syndrome. These patients had ILD if they had evidence of radiographic fibrosis on imaging. Relative and absolute percent change in PFTs (FVC, FEV1 and DLCO) over 1 year were analyzed for prediction of survival (death=mortality) as well as event-free survival (event=death or lung transplant).

They concluded that relative declines of 15% and 10% of FVC over 1 year are the best candidates to predict survival and event-free survival in MA-ILD. They proposed using this outcome criteria of a 10-15% change in FVC over 1 year in clinical trials for MA-ILD.

How do you follow your patients with myositis and ILD? Although helpful for clinical trials, will this change your clinical practice and how these patients are monitored and treated?

More reports from ACR 2015