PREVALENCE OF METACARPAL OSTEOPENIA IN YOUNG RHEUMATOID-ARTHRITIS PATIENTS

The aim of this study was to assess the prevalence of and diagnostic r ole of metacarpal osteopenia in rheumatoid arthritis (RA) and to evalu ate its detectability using receiver operating characteristic (ROC) an alysis. Metacarpal bone mineral density was measured in 98 patients wi th classical RA using a computer-assisted measure of 6 metacarpal diam eters (radiogrammetry) in patients aged less than 50 years. Sensitivit y and specificity of the technique in discriminating the RA patients f rom 85 normal controls and osteopenic RA subjects from their normopeni c counterparts, was determined by standard statistical techniques. Cli nical, laboratory and radiological variables were compared in their ab ility to explain the variance of metacarpal bone density. The prevalen ce of metacarpal osteopenia in RA was 55%, Prolonged disease and reduc ed function significantly differentiated osteopenic from non-osteopeni c RA patients. Discriminant analysis of the RA and control groups show ed that measurement of 6 metacarpals was more accurate than the 2nd me tacarpal measurement alone in predicting the RA patients. The sum of 6 metacarpal combined cortical width (CCW) had a sensitivity of 61% and specificity of 68% in discriminating the RA patients from the control s, Receiver operating characteristic curves showed, not surprisingly, that objective measurement of bone diameters was superior to clinical or laboratory measures of disease activity in correctly classifying a randomly chosen RA patient as osteopenic or not, Metacarpal osteopenia is common in RA and it may be a useful measure of the disease in youn g patients.