A measure of limited joint motion and deformity correlates with HLA-DRB1 and DQB1 alleles in patients with rheumatoid arthritis
- aDepartment of Medicine, University of Ottawa, Canada, bDepartment of Medicine, Montreal General Hospital Research Institute, McGill University, Montreal, Canada
- Dr J Karsh, Ottawa Hospital-General Campus, 501 Smyth, Ottawa, Ontario, Canada K1H 8L6.
- Accepted 15 July 1999
Abstract
OBJECTIVE To assess factors associated with a poor outcome in rheumatoid arthritis (RA), a measure was developed of limited joint motion and deformity, a deformity index (DI), and correlated biochemical and genetic variables with the magnitude of the DI.
METHODS Forty patients were evaluated in a cross sectional study. Clinical measures included the DI and Health Assessment Questionnaire, and disease variables included the erythrocyte sedimentation rate, C reactive protein, rheumatoid factor, and HLA-DRB1 and DQB1 alleles.
RESULTS Significant correlations were noted between increasing DI and duration of RA and concentration of C reactive protein. Patients with a DQB1*301 allele or DR4 allele had a higher DI than those without, and a positive trend was noted between increasing DI and dose of DRB1 RA susceptibility alleles. The trend was lost when a non-linear regression technique was used to remove the effect attributable to C reactive protein, suggesting an interrelation between persistent inflammation and genetics in determining total joint damage.
CONCLUSIONS The DI may be useful to study interactions between genetic and inflammatory processes in rheumatoid disease progression.
