The bone mineral density (BMD) measurement of the hand in rheumatoid arthritis (RA) patients is no standard measurement method as yet. The aim was to contribute to the standardization of the hand BMD measurement, especially of periarticular regions. As results, we found best precision values for the wrist and a significant correlation between hand and spine/femur BMD depending on disease activity and disease duration.
This study was conducted to investigate (i) the precision of periarticular hand BMD measuring, (ii) the periarticular demineralization of the hand, (iii) the correlation between periarticular hand BMD and spine/femur BMD, and (iv) the correlation of hand BMD to hand synovitis.
A number of 52 RA patients were examined by BMD measurement of the femoral neck, spine, whole hand, metacarpophalangeal (MCP) joints II-V, personal identity profile (PIP) joints II-V, and wrist using dual-energy X-ray absorptiometry (DXA). Synovitis of the hand was examined by ultrasonography and magnetic resonance imaging (MRI). Three subgroups were further analyzed: early RA, established RA with moderate and with high disease activity. Early RA and established RA patients with high disease activity were Followed up after 12 months.
We found (1) best precision of BMD measurement for the wrist, (2) BMD in RA significantly reduced if compared to normal controls, (3) a highly significant positive correlation between hand and spine/femur BMD and the power of correlation to depend on disease activity and disease duration (high correlation in RA with moderate disease activity and early RA, very high correlation in RA with high disease activity), (4) a negative correlation between hand BMD and hand synovitis in RA with high disease activity, and (5) a significant reduction of synovitis but no change in hand BMD after 12 months, respectively.
This study shows a highly significant correlation between hand BMD and spine/femur BMD in RA patients depending on disease activity and disease duration. We conclude to measure BMD at different sites including hands in order to quantify bone loss in RA patients most properly.