Relationship between early bone mineral density changes and long-term function and radiographic progression in rheumatoid arthritis

OBJECTIVE: To ascertain whether bone mineral density loss during the first year of treatment for early rheumatoid arthritis (RA) as assessed by dual x-ray absorptiometry (DXA) is associated with long-term function, quality of life, and radiographic progression.

METHODS: Early RA patients, prior to commencing disease-modifying antirheumatic drug therapy, underwent evaluation with DXA scans of both hands, femoral neck, and lumbar spine at the time of diagnosis, then at 1 year and final followup at >6 years. Clinical and laboratory data and hands and feet radiographs were obtained at baseline and final followup.

RESULTS: Sixty-four patients were assessed. At baseline, median disease duration was 6 months, mean 28-joint Disease Activity Score was 5.85, and median Health Assessment Questionnaire score was 1.38. Median followup was 6.4 years (range 5.1-7.2 years). For erosion scores, 86% of patients with hand bone density loss above the smallest detectable change after 1 year progressed versus 55% of those with no hand bone density loss (P = 0.006). However, baseline radiographs showed a similar strength of association. Eighty-four percent of patients with erosions at baseline had erosion progression versus 57% of those with no baseline erosions (P = 0.021). Additionally, first-year bone density loss was not associated with function and quality of life status at followup.

CONCLUSION: Hand bone loss during the first year of treatment in early RA, as assessed with DXA, was associated with a high likelihood of radiographic progression; however, in the current study this was not superior to baseline radiographs. Furthermore, it was not associated with patient-reported outcomes.