Radiographic absorptiometry of the phalanges as a screening instrument to detect osteoporosis of the hip

Objective: To determine the validity of radiographic absorptiometry (RA) of the phalanges in detecting osteoporosis of the femoral neck, measured by d ual energy X-ray absorptiometry (DXA). Material and Methods: In a group practice, 494 Causasian women aged 55 to 8 4 years were recruited. Hand radiographs and DXA measurements of the hip we re performed in 449 women. 409 (91.1%) hand radiographs had sufficient qual ity for analysis by RA. Change of bone mass by age was obtained by using li near regression. Correlations between RA and DXA were calculated. Sensitivi ty and specificity of RA were calculated for several RA cut-off levels. Results: The mean bone mineral density at the femoral neck was 0.866 g/cm(2 ) and 92.57 arbitrary units at the phalanges. A moderate correlation of 0.5 3 (p<0.01) was found between RA and DXA. Depending on the cut-off level use d, the sensitivity and specificity of RA in detecting osteoporosis at the f emoral neck was 0.84-0.55 and 0.61-0.88, respectively. Conclusion: RA may be used as a screening technique to detect osteoporosis, but confirmation is necessary in the subgroup with a positive outcome on R A.