Background/Purpose:

Lung involvement in rheumatoid arthritis (RA) has been recognized as an important contributor to morbidity and mortality. While interstitial lung disease (ILD) is a well-recognized manifestation more common in seropositive RA, the association between RA and other respiratory outcomes such as chronic obstructive pulmonary disease (COPD) and bronchiectasis are less understood. The purpose of this study was to describe imaging abnormalities in clinically-indicated chest computed tomography (CTs) of patients with RA and compare abnormalities based on serologic status.

Methods:

We identified patients within a single-center registry composed of 1,500 RA patients with prospective measures of RA characteristics and detailed clinical data who had clinically-indicated chest CTs. We extracted data by reviewing the initial clinically-indicated chest CT report occurring after baseline study visit. We described the proportion of patients with imaging findings and impression in the report from the attending radiologist. We further stratified the characteristics by RA serostatus (seropositive as rheumatoid factor and/or anti-cyclic citrullinated peptide positivity; seronegative as both negative). We compared patients with seropositive RA to seronegative RA using t-tests or Wilcoxon rank-sum tests for continuous variables and chi-square tests or Fisher’s exact tests for categorical variables.

Results:

We analyzed 188 patients with chest CTs performed after study baseline. The mean age was 64.3 years (SD 11.9), 79.8% were female, mean RA duration was 21.4 years (SD 13.3), mean body mass index (BMI) was 27.5 kg/m² (SD 6.3), 60.1% were ever smokers, and 73.4% were seropositive. Most CTs were obtained to rule out respiratory illness (43.1%), followed by malignancy (24.5%). The most common chest CT pattern abnormalities were: pulmonary nodules (38.8%), opacities (24.5%), and pleural effusions/thickening (18.1%). The most common final impressions for the chest CTs were: pulmonary nodules (30.3%), atelectasis (21.3%), and ILD (16.0%). Only 11.7% of chest CTs had completely normal final impressions. There were no statistically significant differences between seropositive and seronegative RA, including ILD (p=1.0), bronchiectasis (p=0.21), and COPD (p=0.78).

Conclusion:

A wide variety of chest CT abnormalities were present at high prevalence in both seropositive and seronegative RA patients with few having normal findings. While we found no differences based on serostatus in these clinically-indicated chest CTs, there may be differences in the subclinical natural history of lung disease based on RA serostatus and disease activity. The pathogenesis, clinical manifestations, and outcomes of patients with pulmonary abnormalities warrant further research.

Table. Chest computed tomography (CT) findings in patients with seronegative vs. seropositive rheumatoid arthritis (RA)