Hoff M et al. (2007) Hand bone loss as an outcome measure in established rheumatoid arthritis: 2-year observational study comparing cortical and total bone loss. Arthritis Res Ther [doi:10.1186/ar2280]

Hand bone measurements that show periarticular bone loss have previously been proposed as outcome measurements in patients with early rheumatoid arthritis (RA). Since joint inflammation might occur throughout the entire course of disease, Hoff et al. undertook a longitudinal study to compare dual-energy X-ray absorptiometry (DXA) and digital X-ray radiogrammetry (DXR) measurements of hand bone mineral density (BMD) as potential outcome measures in patients with prolonged disease.

In this study, DXR and DXA BMD measurements were taken for both hands in 215 patients with RA, and were analyzed as average values to avoid bias regarding the dominant and nondominant hands. The participants had mean disease duration of 9 years at the start of the study and were analyzed at two consultations separated by a period of 2 years.

Although DXA measurements only showed significant hand bone loss for those patients who started the study with a disease duration of ≤3 years, DXR measurements showed significant loss in hand BMD regardless of the patient's disease duration. At the start of the study, hand BMD was significantly lower in patients with high disease activity than in other patients, when measured by either DXR or DXA. Hand bone loss also correlated with disease activity when measured by DXR, but not by DXA; patients with high disease activity had greater loss than those with lower activity.

The authors conclude that although hand DXA BMD measurements can only be used as outcome measures for early RA, DXR BMD might be used to provide outcome measures throughout the entire course of disease.