A comparison of bone loss in early and late rheumatoid arthritis using quantitative phalangeal ultrasound

Abstract

This study compares amplitude-dependent speed of sound (AD-SoS) measured by phalangeal ultrasonography in a group of 60 patients with early rheumatoid arthritis (RA) with those who had had the disease for more than 4 years. The mean duration of the early disease group was 1.4 years, and the mean of the established RA group was 14.6 years. Plasma viscosity (PV), C-reactive protein (CRP) and HAQ scores were obtained. Forty-nine patients with early RA had hand radiographs assessed by the Larsen score method. The DBM Sonic system was assessed on normal volunteers and a coefficient of variation of 0.88% obtained. A significant correlation was found between the left and right hands of the patients groups studied (r=0.84). The mean Z score of both hands was therefore used in comparing the two clinical groups. Results showed no correlation between CRP, PV and Z scores of AD-SoS. The HAQ scores showed a weak negative correlation, and there was no correlation between the Larsen score and Z score, or the number of swollen joints and Z score. However, the early and established groups with RA were significantly different (#E5/E5#=0.004). Within the early RA group the Z score for AD-SoS was lower in those with disease duration of less than 2 years (−1.71) than in those with disease duration of 2–4 years (−1.01). This suggests that bone loss in the fingers is greater in the first 2 years of disease than in the following 2 years, which might reflect an effect of treatment.