[Bone densitometry in patients with rheumatoid arthritis].

Osteoporosis (OP) is a frequent complication of rheumatoid arthritis (RA) and longitudinal studies have documented increased rate of bone loss in RA patients. To determine the frequency of low bone mass as well as the influence of disease duration and corticosteroid use on bone mass in patients with RA, 88 patients with RA and 112 age matched controls were studied. Bone densitometry was performed by a single dual X-ray absorptiometry equipment in the lumbar spine (LS) and femoral neck (FN). The mean age of patients and controls were 52.6 and 54.6 years, respectively. The mean disease duration was 7.0 years and 79.5% of patients were taking 5.0 mg prednisolone daily for a mean period of 4.6 years. At the FN, 45% of patients had OP compared to 30.4% in the controls (P < 0.05). At the LS the frequency of OP in patients was non-significantly lower than in the controls. OP was more frequent in corticosteroids treated patients compared to non-corticosteroids treated patients both at the FN (43.5% vs 39%) and LS (26% vs 22%) but the differences were not significant. Disease duration longer than 10 years in comparison to disease duration of less than two years was associated with bone mineral density change of -10.9% at the FN (P = 0.05) and -10.4% at the LS (P not significant). The results of this study indicate that a significant proportion of patients with RA have OP at the FN and LS, and disease duration longer than 10 years is associated with a significant increase in bone loss. Acta Medica Iranica, 43(2): 99-104; 2005