A group of international researchers have identified and validated a risk score for the early detection of high-risk subclinical RA-associated interstitial lung disease (ILD). This risk score comprised of four independent variables namely sex, age at RA onset, RA disease activity computed using DAS28-ESR and the MUC5B rs35705950 genetic variant.
The researchers recruited patients without pulmonary symptoms from 2 RA cohorts into discovery (n=163) and replication population (n=89), and all of them underwent chest HRCT scans and genotyping for MUC5B rs35705950. A risk score based on independent risk factors was developed in the discovery population and it was validated in the replication population.
The corresponding prevalence of subclinical RA-ILD noted were 19.0% and 16.9%, respectively. The independent risk factors for subclinical RA-ILD identified in the discovery population were the MUC5B rs35705950 T risk allele (OR=3.74), male sex (OR=3.93), older age at RA onset (OR for each year =1.10) and increased mean DAS28-ESR (OR for each unit =2.03). Based on these independent variables, the scientists developed and validated a derived risk score with AUC=0.82 and 0.78 respectively. However, the exclusion of MUC5B rs35705950 gene variant from the model yielded a lower goodness of fit (P=0.01).
The presentation of subclinical RA-ILD course is heterogeneous, and it is associated with substantial morbidity and mortality. The ILD screening is highly challenging in high-risk patients with no specific respiratory symptoms. Improved risk stratification of subclinical RA-ILD could be beneficial in future recommendations in disease screening. This revolutionary finding of a risk score would help clinicians in identifying RA patient at high risk, without pulmonary symptoms, in routine clinical practice.
Reference: Juge PA, Granger B, Debray MP, et al. A Risk Score to Detect Subclinical Rheumatoid Arthritis-Associated Interstitial Lung Disease [published online ahead of print, 2022 May 18]. Arthritis Rheumatol. 2022;10.1002/art.42162.