Longitudinal study of hand bone densitometry in rheumatoid arthritis

To measure hand bone mineral content (BMC) by dual x-ray absorptiometry and to seek clinical correlates in patients with rheumatoid arthritis (RA), in a prospective, longitudinal study.

Eighty-one patients with non-steroid-treated RA were assessed at baseline and at month 12, for hand BMC and for disease activity and severity. Hand BMC in patients was compared with that in a control group of 95 normal volunteers, and rate of loss was compared with that in 37 controls.

At the initial assessment, male and female patients with RA had lower hand BMC than controls, after correction for age, height, and weight (mean reduction 7.5% in men [P = 0.003] and 7.8% in women [P = 0.01]). After 1 year, there was a further loss of hand BMC in patients (median loss 3.25% in men [P = 0.001] and 1.46% in women [P = 0.05]), but normal controls did not have significant changes in their hand BMC. In patients with disease duration of < 2 years at study entry, the parameters of disease activity improved over 1 year, but they lost significant amounts of hand BMC. Hand BMC loss correlated with baseline C-reactive protein levels. In those with RA of > 2 years duration at entry, the Health Assessment Questionnaire scores and Larsen scores had worsened after 1 year, but there was no significant loss of hand BMC.

Patients with RA had low hand BMC compared with normal controls, even within 2 years of disease onset. The rate of loss was highest in patients with early disease and correlated with measures of initial disease activity. This loss continued despite clinical improvement.