Predictors of mortality in rheumatoid arthritis-associated lung disease: A retrospective study on ten years

Rheumatoid arthritis (RA)-associated lung involvement is a cause of mortality. This study aimed to evaluate mortality rate and mortality-associated factors in RA patients with high-resolution computed tomography (HRCT)-proven lung involvement.

Patients followed-up for RA between 2010 and 2018 were evaluated regarding HRCT-proven lung involvement. The present study was designed as a single-centre, retrospective and descriptive study. The HRCT reports of patients were re-evaluated for three major patterns: UIP, nonspecific interstitial pneumonia (NSIP), and isolated airway disease (AD). Mortality rates and its associated factors (demographic characteristics, RA-related factors and lung-involvement-related factors) were determined.

The study included 156 patients (females, 68.3%) with radiologically confirmed RA-associated lung disease. The mean age was 55.5 (12.1) years at RA diagnosis and 62.7 (9.7) years at the diagnosis of lung involvement. The patterns of lung involvement on HRCT were UIP in 89 (57.0%) patients, NSIP in 51 (32.7%) patients, and isolated AD in 16 (10.3%) patients. The RA patients were followed-up for a mean of 10.2 (7.4) years and they were followed-up for a mean of 4.5 (3.7) years after interstitial lung disease (ILD) diagnosis. Overall, 40 (25.6%) patients died. The 5-year survival rate was 78%. Multivariate analysis revealed UIP pattern (log-rank test, P<0.01), pleural effusion (log-rank test, P<0.05), and a shorter time interval (<3 years) between the diagnoses of RA and RA-ILD (log-rank test, P<0.01) to be independent predictors of mortality.

In addition to the UIP, a known risk factor, pleural effusion and the short time between the diagnoses of RA and ILD were also found to be associated with mortality.