Bone demineralization observed in early rheumatoid arthritis is not easily measured. To measure bone loss and to discriminate between rheumatoid arthritis and other rheumatic diseases, we used two methods: dual-energy X-ray absorptiometry and ultrasonography.
From a population-based recruitment, 32 patients with early peripheral polyarthritis (median disease duration: 4 months) were studied. Clinical, laboratory, functional, hand-bone assessments were made at the entry an at months 6 and 12. Bone X-ray densitometry measurements were made on 16 areas of the hand. Speed of sound was measured across the proximal phalanges of the four fingers. X-rays of both hands were scored according to the modified Sharp's score. At 12 months, patients were classified as rheumatoid arthritis (N = 15; 9 F) or as other rheumatic diseases.
We found: 1) significantly decreased bone mineral density (BMD) of the whole hand, in the rheumatoid arthritis group versus the other rheumatic diseases group, at 6 and 12 months (P < 0.05); 2) no significant decrease of bone mineral density (BMD) in other areas in the rheumatoid arthritis group; 3) no significant change of ultrasounds in either group; and 4) no significant correlation between the decrease of BMD in the rheumatoid arthritis group and clinical, biological or radiologic parameters, except for IFNgamma, whose production in whole blood cell culture was lower at entry in the rheumatoid arthritis group.
DEXA bone assessment in rheumatoid arthritis was able t detect bone loss in the whole hand at 6 months.