Bone resorption and inflammatory inhibition efficacy of intermittent cyclical etidronate therapy in rheumatoid arthritis.

OBJECTIVE: Osteoclast activation or cartilage and bone destruction are developed in patients with rheumatoid arthritis (RA). The efficacy of etidronate with respect to osteoporosis, inhibition of bone resorption and destruction, and antiinflammation in RA was examined for 72 weeks. METHODS: Sixty-three patients with RA (56 women, 7 men) were divided into a group that received intermittent cyclical etidronate therapy (ICET) (31 patients) and a non-ICET group (32 patients). Over a 72 week followup period, the urinary deoxypyridinoline (DPD), serum bone alkaline phosphatase (BAP), bone mineral density (BMD), Larsen damage score, Lansbury activity index, and concentrations of serum C-reactive protein (CRP) and serum interleukin 6 (IL-6) of the 2 groups were compared. RESULTS: In the non-ICET group, a significant decrease in BMD and a significant increase in the Larsen damage score were observed. In the ICET group, the level of DPD started to decrease 12 weeks after etidronate administration and progression of the Larsen damage score was significantly inhibited. IL-6 concentration was significantly decreased 72 weeks after etidronate administration. Concentrations of BAP and CRP and the Lansbury activity index were not significantly different between the ICET and the non-ICET groups. A significant correlation between the IL-6 and DPD concentrations was observed. CONCLUSION: Etidronate was effective at inhibiting bone resorption and destruction in study patients with RA, while not increasing BAP concentrations; and a correlation was observed between the concentration of DPD and IL-6, indicating the antiinflammatory effect of etidronate.