Clinical associations of dual-energy X-ray absorptiometry measurement of hand bone mass in rheumatoid arthritis.

Hand bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA) has potential as a marker of progression in early rheumatoid arthritis (RA). We examined a DXA methodology and studied in a cross-sectional manner 202 patients with RA. Hand BMD correlated inversely with age and was higher in males. Hand BMD correlated with lumbar and femoral sites. In females, BMD of the hand correlated positively with grip strength and negatively with disability. Those with higher C-reactive protein (CRP) had significantly lower hand BMD than those with normal CRP. In patients with a normal CRP, the hand BMD:lumbar BMD ratios were significantly higher in patients with longer disease duration. Hand BMD correlates with measures of disease activity, functional capacity and also with lumbar and femoral BMD. Hand bone loss occurs in early disease, in the absence of detectable systemic disease, and before lumbar BMD loss. It has the potential to be an outcome measure in early disease.