Hand bone loss measured by digital X-ray radiogrammetry is a predictor of joint damage in early rheumatoid arthritis

The aim of this study was to evaluate whether loss of bone measured by digital X-ray radiogrammetry (DXR) of hands early in the course of rheumatoid arthritis (RA) may predict future radiographic joint damage after 1 and 2 years.

A total of 166 patients with early RA, who were part of the Better Anti-Rheumatic FarmacOTherapy (BARFOT) low-dose prednisolone study, were included. The patients had been randomized to treatment with 7.5 mg prednisolone daily or no prednisolone when they started with their first disease-modifying anti-rheumatic drug (DMARD) therapy. Radiographs of hands and feet were taken at baseline and after 1 and 2 years and assessed by the van der Heijde modified Sharp (vdH-S) score. Hand bone density (HBD) was measured on the same radiographs by DXR. Changes in HBD and hand bone loss (HBL) were calculated. HBL was defined as a change in DXR bone mineral density (DXR-BMD) during the first year by more than 0.0048 g/cm(2).

HBL was found in 64% of the patients. Patients with HBL had radiological progression significantly more often than patients without (80% vs. 57%, p=0.012). Patients not treated with prednisolone had HBL more often than patients with this treatment (83% vs. 44%, p=0.001). In multiple regression analyses, HBL and change in DXR-BMD during the first year proved to be independent predictors of radiological progression.

Loss of bone measured by DXR was found to be an independent predictor of radiological joint damage and may thus be an additional tool in the process of treatment decision in early RA.