Study Findings Show IPF Methods For Predicting Mortality Also Work For SSc-ILD

Recently, a group of researchers from University of British Columbia in Vancouver, Canada released study results in which they found that mortality risk prediction models used to clinically assess the 1-year survival rate for patients with idiopathic pulmonary fibrosis (IPF), could also be utilized to accurately predict short-term mortality in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD).  The study, entitled, “Predicting mortality in systemic sclerosis-associated interstitial lung disease using risk prediction models derived in idiopathic pulmonary fibrosis,” was published in the latest edition of CHEST Journal.

ILD is a detrimental diagnosis as well as a leading cause of mortality in patients with SSc. Patients diagnosed with SSc-ILD most often experience damage to the tissues of the lungs that results in reduced respiratory function and ultimately death.

There are currently several mortality-risk prediction models, such as the du Bois index, Composite Physiologic Index, and modified du Bois index, used by clinicians to estimate survival times in patients with IPF.  It is unknown whether these models can also be utilized to successfully predict survival times in patients with SSc-ILD.

To answer this question, the researchers recruited 156 patients with SSc-ILD, and measured their 1-year mortality with the following clinical assessments: pulmonary function tests, 6-minute walk tests, and echocardiograms.

The primary study finding showed that after analysis, all testing measures for IPF were significant predictors of 1-year mortality in SSc-ILD.  Other important findings included:

• Every predictor model included forced vital capacity.
• The 6-minute walk distance was identified as an independent predictor of 1-year mortality.

When discussing the study’s findings, Dr. Christopher J. Ryerson, MD, assistant professor in the James Hogg Research Centre at the University of British Columbia, corresponding study author, and his colleagues wrote, “We show that the modified du Bois index has good discrimination and calibration for the prediction of 1-year mortality in SSc-ILD, and that discrimination is also acceptable for the Composite Physiologic Index, interstitial lung disease-gender, age, physiology, and original du Bois index.”

The researchers also recognized a need for further research, “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. Future studies are also needed to determine whether novel mortality risk prediction tools can substantially improve prognostication in patients with SSc-ILD.”