Prevalence of decreased bone mass in rheumatoid arthritis. Relation to anti-inflammatory treatment.

The bone mineral content (BMC) in both forearms (highly correlated to total body calcium) was measured by photon absorptiometry in a representative sample of rheumatoid arthritis outpatients comprising 129 patients treated with either gold salts (n = 29), penicillamine (n = 61), prednisone (n = 24), or other anti-RA drugs (n = 15). The mean BMC value was 84% of normal (p less than 0.001) with the lowest mean value in the group treated with prednisone (73% of normal). The patients as a group had hypocalcaemia (p less than 0.001), raised serum alkaline phosphatase (p less than 0.001), and normal urinary excretion rates of calcium and hydroxyproline. These results indicate that RA patients have disturbances in their calcium and bone metabolism.