Evaluation of finger ultrasound in the assessment of bone status with application of rheumatoid arthritis

Osteoporosis associated with active rheumatoid arthritis (RA) has been demo nstrated in both the axial and peripheral skeleton, especially the periarti cular regions more directly affected by the disease. Quantitative ultrasoun d (QUS) is a recently accepted tool for the assessment of bone status, and therefore could be used to monitor bone changes in RA patients. In a cross- sectional study we measured ultrasound velocity (Ad-SOS) through the proxim al phalanges in three groups of female subjects. These included: 51 patient s with rheumatoid arthritis (group 1), 44 general practitioner (GP)-referre d patients for osteopenia (group 2) and 52 young healthy volunteers (group 3), For groups 1 and 2 bone mineral density (BMD) of the lumbar spine and p roximal femur were also measured. For the RA patients BMD of the hand, meas urement of hand function (HAQ and grip strength) and disease activity (ESR and CRP) were also assessed. The precision of long-term Ad-SOS measurements on volunteers gave a root mean square coefficient of variation (CV) of 0.7 % and standardized CV of 3.6%. No statistically significant effect uf domin ance was observed in the measured Ad-SOS between the dominant and non-domin ant hand (r = 0.96, p < 0.001). Ad-SOS was found to be significantly differ ent in the three groups (p < 0.0001). Ad-SOS was highly dependent on age (r = -0.67), with a gradual reduction (-5.2 m/s per year) after the age of 30 years for female patients in both group 1 and group 2. Ad-SOS was signific antly correlated with lumbar spine, femoral neck and hand BMD, with correla tion coefficients of 0.49, 0.51 and 0.72 respectively for RA patients. Fing er ultrasound was moderately correlated with measures of hand function, wit h coefficients of 0.37 and 0.39 for HAQ and grip strength respectively. Han d BMD also correlated to the same power with these parameters. Neither fing er ultrasound nor BMD was significantly correlated with ESR and CRP (measur es of disease activity). We have demonstrated that bone status can be asses sed quickly and cheaply using a portable QUS device. Ad-SOS relates to the measure of hand function in RA patients. Longitudinal studies are required to determine the usefulness of finger ultrasound fur monitoring disease pro gression or the effect of treatment in RA.