Baseline Lung Function and Inflammation Signal Poor Outcomes in Systemic Sclerosis Interstitial Lung Disease: Study
Canada: Researchers from the University of British Columbia, led by Dr. Boyang Zheng, have highlighted the importance of early identification of patients at risk for rapid lung function decline in systemic sclerosis-associated interstitial lung disease (SSc-ILD). Their recent multicenter retrospective study, published in Rheumatology, sheds light on the different patterns of lung function deterioration in SSc-ILD and their implications for survival.
The researchers reported, "The EUSTAR study revealed that a decline of over 10% in forced vital capacity (FVC) within one year significantly raised mortality risk (HR 3.81) in SSc-ILD patients. Combining FVC decline with skin score changes (HR 2.82) or a ≥15% drop in DLCO (HR 3.42) further predicted poorer survival outcomes."
Systemic sclerosis (SSc) is a complex autoimmune condition, and interstitial lung disease remains one of its most severe complications, contributing significantly to morbidity and mortality. The study focused on evaluating forced vital capacity (FVC)—a key measure of lung function—over time in 444 patients with SSc-ILD and a disease duration of seven years or less.
Using a statistical modeling technique known as latent class analysis, the researchers grouped patients based on how their FVC levels changed over time.
The findings of the study were as follows:
- Four distinct forced vital capacity (FVC) trajectory patterns were identified in patients with systemic sclerosis-related interstitial lung disease (SSc-ILD).
- One group exhibited a clearly progressive decline in lung function, with an average annual FVC reduction of 2.18%.
- The other three groups showed either stable or slow progression of FVC decline.
- Patients in the rapidly progressive FVC group had a significantly higher risk of mortality compared to those in the stable/slow progression groups.
- The hazard ratio for mortality in the progressive group was 2.95 (95% CI: 1.74–4.98).
- Lower baseline FVC and elevated C-reactive protein (CRP) levels were associated with an increased risk of rapid FVC decline.
- A baseline FVC of 72% or lower predicted progressive decline with 88% sensitivity and 91% specificity.
- Lower initial FVC was more frequently observed in older patients, individuals of Caucasian ethnicity, those with longer disease duration, the presence of anti-topoisomerase I antibodies (ATA), and elevated CRP.
These findings reinforce the value of early pulmonary assessment in patients with SSc-ILD. They also suggest that initial disease severity, as measured by FVC and CRP, can serve as reliable indicators of future disease progression and survival.
While the study offers crucial insights, the researchers emphasize the need for additional research to refine predictive models using imaging and other clinical data. Early identification of high-risk patients could pave the way for timely therapeutic intervention and improved outcomes.
Reference:
Zheng, B., Nikpour, M., Stevens, W., Proudman, S., Morrisroe, K., Wang, M., Man, A., BaronP, M., Interest Group, A. S., Apostolopoulos, D., Brown, Z., Cooley, H., Croyle, L., De Jager, J., Fairley, J., Ferdowsi, N., Frade, S., Girgis, L., Gregory, K., . . . Thorne, C. Predicting trajectories of lung function decline in systemic sclerosis related interstitial lung disease. Rheumatology. https://doi.org/10.1093/rheumatology/keaf270
