Risk Factors for Rheumatoid Arthritis-associated Interstitial Lung Disease Save

Sparks and colleagues have published a matched cohort analysis demonstrating risk factors that may augment the risk of rheumatoid arthritis (RA)-associated interstitial lung disease (ILD), especially the combination of obesity, high CRP, high MD-HAQ and >30 pack-year smoking history. 

This nested case-control study compared incident RA-ILD to RA non-ILD controls and examined clinical, laboratory and lifestyle factors that may predict RA-ILD.

This included 84 RA-ILD and 233 matched non-ILD RA control patients. 

An increased risk of RA-ILD was associated with:

• Obesity (OR 2.42, 95% CI 1.11–5.24 vs normal BMI)
• High-positive CRP ≥ 10 mg/L  (OR 2.61, 95% CI 1.21–5.64 vs CRP < 3 mg/L) 
• Poor functional status (by MDHAQ ≥ 1)  (OR 3.10, 95% CI 1.32–7.26 vs MDHAQ < 0.2).
• Smoking >30 pack-years (OR 6.06, 95% CI 2.72–13.5 vs never smokers) 

Overall, lifestyle and clinical risk factors for RA-ILD had an AUC of 0.79 (95% CI 0.73–0.85), suggesting the overall ability to predict RA-ILD remains modest.