Whole-hand and regional bone mineral density involvement in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by symmetric polyarthritis that can lead to joint deformity, disability, and osteoporosis. We aimed to evaluate whole hand and regional BMD in RA patients compared to controls. In addition, we evaluated the BMD of dominant versus non-dominant hands in healthy subjects. We included adult female and male RA patients and control subjects matched by age, sex, and BMI. BMD (g/cm²) was measured by DXA in lumbar spine (LS), whole hand, and three regions of interest: carpus, metacarpal bones, and phalanges. Results: 44 control subjects (49.5±11.8 y) and 60 with RA (52.7±12.7 y) were included. Significant lower BMD in RA patients was found in LS (-8.7%), dominant whole hand (-9.5%), carpus, metacarpal bones, and phalanges, and non-dominant whole hand (-8.7%), metacarpal bones, and phalanges compared to controls. A significant positive correlation was found between LS and whole-hand BMD (dominant r=.63, non-dominant r=.67). Finally, the whole hand, metacarpal bones, and carpus BMD measurements were significantly higher in the dominant hand compared to the non-dominant hand without differences in the phalangeal ROI. In conclusion, hand BMD was significantly lower in RA patients compared to control subjects and there was a significant correlation with LS BMD. We demonstrated that BMD measurements of the whole-hand, and different ROI (carpus, metacarpal bones, and phalanges) by DXA would be an easily reproducible technique to evaluate bone loss. In addition, the whole hand, metacarpal bones and carpus BMD measurements were significantly higher in the dominant hand compared to the non-dominant hand without differences in the phalanges.