Researchers Develop Idiopathic Pulmonary Fibrosis Prediction Models For Mortality in SSc-ILD Patients

According to a recent study published in the journal CHEST, the official journal of the American College of Chest Surgeons, several mortality-risk prediction models used in assessing mortality at 1-year in patients with idiopathic pulmonary fibrosis may also be a viable option in gauging short-term mortality in patients suffering from systemic sclerosis-associated interstitial lung disease (SSc-ILD).

Interstitial lung disease (ILD) is a devastating and significant cause of death in patients with a rare type of scleroderma called systemic sclerosis (SSc).  Affecting about 20 people per million in the United States annually, systemic sclerosis is an autoimmune disease which can potentially affect multiple organs of the gastrointestinal, cardiac, renal, and pulmonary systems.

“We show that the modified du Bois index has good discrimination and calibration for the prediction of 1-year mortality in [systemic sclerosis-associated interstitial lung disease (SSc-ILD)], and that discrimination is also acceptable for the [Composite Physiologic Index (CPI)], [interstitial lung disease-gender, age, physiology (ILD-GAP)] and original du Bois index,” said Christopher J. Ryerson, MD, assistant professor in the James Hogg Research Centre at the University of British Columbia and colleagues.

In their study titled “Predicting mortality in systemic sclerosis-associated interstitial lung disease using risk prediction models derived in idiopathic pulmonary fibrosis,” the researchers evaluated 156 SSc-ILD patients. To estimate 1-year mortality rates, they used four baseline risk prediction models, which included the ILD-GAP Index, the Composite Physiologic Index (CPI), the du Bois index, and the modified du Bois index.

The results revealed that from the time of SSc-ILD diagnosis, the median survival was of 15.0 years. Results also showed that all baseline models were predictors of 1-year mortality in patients with SSc-ILD. The modified du Bois index had an AUROC curve of 0.84, in comparison to 0.77 to 0.81 in the other models. Statistical analyses also revealed that all baseline models include forced vital capacity, and 6-minute walk distance was a predictor of 1-year mortality of SSc-ILD.

“Additional studies are required to determine how to translate these models into specific mortality estimates in SSc-ILD and how these estimates should then be used in clinical practice,” the researchers wrote according to a news release. “Future studies are also needed to determine whether novel mortality risk prediction tools can substantially improve prognostication in patients with SSc-ILD.”