Genotyping for disease associated HLA DR beta 1 alleles and the need for early joint surgery in rheumatoid arthritis: a quantitative evaluation

Objective-To determine the value of HLA DR beta 1 disease associated epitop e (DAE) and erythrocyte sedimentation (ESR) in predicting the need for majo r joint replacement in rheumatoid arthritis (RA). Methods-Sixty five RA patients who had undergone hip, knee or shoulder arth roplasty within 15 years of disease onset and 65 who had not, HLA DR beta 1 genotype was determined by polymerase chain reaction. ESR at first hospita l visit was noted. Results-Significantly more patients with two DAE required surgery, (32% a 9 %), chi(2) = 13.9, p=0.001, odds ratio=5.4 (95% CI: 1.8, 16). Sensitivity w as poor, 32%, specificity high, 91%. Presentation ESR was higher in surgery patients compared with non-surgery patients, 52 mm 1st h v 25 mm 1st h, p< 0.001, but was independent of DAE status. Sensitivity of an ESR of 30 mm 1 st h was 75%, specificity 53%. Conclusion-The presence of two DAE is a risk factor for major joint surgery in RA and is independent of ESR, whereas in those with one or no DAE, a hi gh ESR is an important predictor.