Development of a risk indicator score for the identification of interstitial lung disease in patients with rheumatoid arthritis

Abstract

BackgroundClinically evident interstitial lung disease (ILD) affects 10%–42% of RA patients with prognostic implications. The aim of this study was to discern which factors are associated with the presence of ILD in RA patients and to develop a score that could help to stratify the risk of having ILD in RA patients. MethodsCase–control study. We included RA patients recruited from ILD and rheumatology clinics. We retrieved the following data: gender, age, presence of extra articular manifestations, disease activity scores, antibodies status, ESR, and medication use. Multivariate logistic regression was performed. A risk indicator score was developed. ResultsOf 118 patients included in this study, 52 (44%) had RA-ILD (cases) and 66 (56%) had RA without ILD (controls). Twenty-six patients were male (22%), the mean age was 56.6±15.6 years. Five variables were significantly associated with the presence of ILD: male gender, smoking, extraarticular manifestations, a CDAI score>28, and ESR>80mm/h. The AUC of the final model curve was 0.86 (95%CI 0.79–0.92). Two potential cut-off points of the risk indicator score were chosen: a value of 2 points showed a sensitivity of 90.38% and a specificity of 63.64%, while a value of 4 points showed a sensitivity of 51.9% and a specificity of 90.9%. ConclusionThis study identified risk factors that could help identify which RA patients are at risk of having ILD through the development of a risk indicator score. This score needs to be validated in an independent cohort.