Three-Year Experience with Risedronate Therapy for Patients with an Increased Fracture Risk

Abstract

We previously reported that risedronate improved the structural parameters of the proximal femur, as well as lumbar spine and proximal femoral bone mineral density (BMD), after 1 year of therapy by suppressing bone resorption in patients with an increased risk of fracture. Our practice-based observational study was subsequently extended to determine whether these effects were enhanced, maintained or attenuated after 3 years. A total of 174 patients (nine men and 165 postmenopausal women) with a mean age of 67.8 years who had osteoporosis or osteopenia and clinical risk factors for fracture started risedronate therapy. The BMD of the lumbar spine and proximal femur, as well as proximal femoral structural parameters, were evaluated by dual-energy x-ray absorptiometry with advanced hip assessment (AHA) software at baseline and every year for 3 years. Data were available for 107 patients at 1 year, 80 patients at 2 years and 74 patients at 3 years. Lumbar spine, total hip and femoral neck BMD and the cross-sectional area (CSA) of the proximal femur increased from baseline after 1 year with levels being maintained after 2-3 years. The cross-sectional moment of inertia (CSMI) of the proximal femur increased from baseline after 1 year and the increase was enhanced after 2 years with levels being maintained after 3 years. The femoral strength index (FSI) increased from baseline after 1 and 2 years and the increase was enhanced after 3 years. The increases in proximal femoral CSMI and FSI were greater than those of total hip and femoral neck BMD after 3 years of therapy. The present study showed the effects of risedronate therapy for 3 years on the BMD of the lumbar spine and proximal femur, as well as on proximal femoral structure, in patients with an increased risk for fracture.