BONE METABOLISM IN THE EARLY-STAGE OF RHE UMATOID-ARTHRITIS

Secondary osteoporosis is a feature of rheumatoid arthritis (RA). Pati ents suffer from periarticular and also generalised decalcification. T he periarticular form develops earlier than the generalised form, but shows some similar pathologic features. It is thought that bone metabo lism is accelerated in RA. The aim of the present study was to identif y changes in bone metabolism in the early stage of RA (Stad.I, ARA-cri teria). Serum levels of osteocalcin, alkaline phosphatase and ostase ( bone-alkaline phosphatase) (as markers for bone formation) and hydroxy prolin in 24 hour urine samples (as a marker for bone resorption) were determined in 20 patients and in 26 age-matched controls. Bone densit y was examined by dual x-ray absorption (DPX) of the lumbar vertebral column and the ward triangle (left femur). The average duration of ill ness at the onset of the study was 23 months (4-61 months). The patien ts had not received any steroid medication but some were treated with nonsteroidal antirheumatic drugs (NSAID). The parameters of bone forma tion and resorption were not significantly different in patients and c ontrols. The bone density was normal in both groups. Our findings show normal bone metabolism in the early stage of RA. However, further stu dies are required to determine whether osteoporosis can cause signific ant morbidity and reduces quality of life.