Dual-energy X-ray absorptiometry and evaluation of the osteoporosis self-assessment tool in men with rheumatoid arthritis

Males with rheumatoid arthritis (RA) are at risk for osteoporosis but infrequently undergo dual-energy X-ray absorptiometry (DXA). We examined the frequency of DXA in males enrolled in the Veterans Affairs Rheumatoid Arthritis Registry. The Osteoporosis Self-Assessment Tool (OST) index, a formula using age and weight, was calculated for all subjects. DXA was performed on 282 (35.5%) of the males who were younger (p0.01), had lower mean OST index score (p0.05), and were more likely to have been prescribed prednisone (p0.01) than subjects without DXA. Low bone mass (T-score-1) was present in 73% of subjects with DXA; 37% of subjects with low-risk OST index scores had normal bone mineral density (BMD) compared with 5.6% of those with high-risk OST index scores (p0.01). There was a significant but modest correlation between BMD and the OST index (r = 0.17, p0.01). No OST score had a sensitivity and specificity of more than 80%. Association between OST index and BMD was strongest in non-Hispanic whites, subjects older than 60 yr, and smokers. DXA was underutilized in males with RA. The OST index correlated with low bone mass but could not reliably predict osteoporosis in this population.