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

Abstract

To determine the value of HLA DR beta 1 disease associated epitope (DAE) and erythrocyte sedimentation (ESR) in predicting the need for major joint replacement in rheumatoid arthritis (RA). Sixty five RA patients who had undergone hip, knee or shoulder arthroplasty 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 hospital visit was noted. Significantly more patients with two DAE required surgery, (32% v 9%), chi 2 = 13.9, p = 0.001, odds ratio = 5.4 (95% CI: 1.8, 16). Sensitivity was 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 1st h was 75%, specificity 53%. 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 high ESR is an important predictor.