A recent phenome-wide association study approach (PheWAS) identified potential significant links between variations in levels of autoantibodies and comorbidities of interest in rheumatoid arthritis (RA). Researchers analyzed a validated electronic medical record (EMR) RA cohort from 2 tertiary care centers (n=1,006 RA subjects, mean age 61 years, and 79.0% female). They measured 36 autoantibodies targeting epitopes implicated in RA and extracted all ICD-9 codes for each subject and grouped them using a published method into disease categories (PheWAS codes). They found:

• There were 3,568 unique ICD-9 codes grouped into 625 PheWAS codes; 206 PheWAS codes with a prevalence ≥3% were studied.
• PheWAS identified 24 significant associations of autoantibodies to epitopes at FDR≤0.1.
• Associations with the strongest associations and highest positive predictive value (PPV) for PheWAS code included autoantibodies against fibronectin with obesity and fibrinogen with pneumonopathy.
• The latter included diagnoses for cryptogenic organizing pneumonia and obliterative bronchiolitis.