MALMO, Sweden—Hand bone mineral density (BMD) measured by digital X-ray radiogrammetry (DXR) may help doctors better predict risk of joint damage and mortality among individuals with rheumatoid arthritis (RA), suggests a new study in Rheumatology.1

“This supports the concept that diaphysial local bone loss in the hand is a valid measurement of disease activity of damage and has prognostical importance.”—Christina Book, MD
“This supports the concept that diaphysial local bone loss in the hand is a valid measurement of disease activity of damage and has prognostical importance,” conclude the authors who were led by Christina Book, MD, a specialist in rheumatology and internal medicine at Malmo University Hospital in Sweden.

While more studies are needed to flesh out what role the technology will have in clinical practice, DXR “should be done at first visit and then compared with the second visit after 3 or 6 months, in order to see the early stages of bone loss,” she told MSKreport.com.

Low hand BMD predicts worse RA disease activity

In the new study, low BMD in the hand measured by DXR predicted RA-related mortality as accurately—or more accurately—than other measures such as radiographic damage and functional disability, she said.

To arrive at their findings, researchers looked at hand x-rays of 108 RA patients. Of these, 24 patients could not have their X-rays evaluated by DXR due to joint prostheses or severe malalignment. The researchers evaluated BMD by DXR on the same hand X-rays used for scoring radiographic joint damage. They found that 62 of 82 patients died from February 1978 through March 2008. In age- and sex-adjusted proportional hazards models, BMD, Steinbrocker functional class 3-4, the physician's global assessment, and erythrocyte sedimentation rate predicted RA mortality. By contrast, rheumatoid factor, disease duration, Larsen index, Ritchie articular index and the patient's global assessment did not predict mortality.

“Low DXR-BMD predicted overall mortality in age- and sex-adjusted analyses, which further supports it as a valid measurement of disease activity or damage and as having prognostic value,” the study authors conclude.

Reference
1. Book C, Algulin J, Nilssom J-A, et al. Bone mineral density in the hand as a predictor for mortality in patients with rheumatoid arthritis. Rheumatology. [epub ahead of print June 24, 2009]