Evaluation of the effect of 4 months of risedronate therapy on femoral strength using femoral strength analysis tools.

The effect of risedronate (2.5 mg once daily) on femoral strength was evaluated using Advanced Hip Assessment (AHA) for the first time in Japan. In total, 104 patients with primary osteoporosis and available data on bone mineral density (BMD; lumbar spine/proximal femur), urinary NTx (cross-linked N-telopeptides of type I collagen) and AHA-based parameters collected before and after 4 months of risedronate therapy were included in the analyses. Change and percentage change from baseline in these parameters were determined. Percentage change in femur strength index was 7.9 +/- 21.1% and 5.5 +/- 18.0% for the right and left femurs, respectively; both increases were statistically significant. Cross-sectional moment of inertia, cross-sectional area and mean neck width in the femoral neck region of interest also increased significantly in both femurs. Percentage change in lumbar spine BMD (L2 - L4) was 3.0 +/- 3.7%, and proximal femoral BMD was 1.1 +/- 3.1% and 0.7 +/- 3.2% in the right and left femurs, respectively, all showing a significant increase from baseline. Percentage change in urinary NTx was -41.5 +/- 30.5%, which was a significant decrease. Using AHA, this study showed that, in patients with primary osteoporosis, risedronate improved BMD and bone quality, thereby enhancing femoral strength as early as 4 months after treatment initiation.