TY - JOUR
T1 - Subtrochanteric and diaphyseal femur fractures in patients treated with alendronate: a register-based national cohort study
AU - Abrahamsen, Bo
AU - Eiken, Pia
AU - Eastell, Richard
N1 - Keywords: Aged; Aged, 80 and over; Alendronate; Cohort Studies; Cross-Sectional Studies; Denmark; Etidronic Acid; Female; Femoral Fractures; Humans; Incidence; Male; Patient Compliance; Registries
PY - 2009
Y1 - 2009
N2 - Alendronate (aln) is a potent bisphosphonate with a prolonged duration of action. Recent reports have found long-term aln use to be common in patients with subtrochanteric or proximal diaphyseal femur fracture, raising concerns that these fractures could be a consequence of excessive suppression of bone turnover. Two national observational register-based studies were performed: (1) cross-sectional study (N = 11,944) comparing age distribution, exposure, and trauma mechanisms between different types of proximal femur fractures and (2) matched cohort study in patients with prior nonhip fractures (N = 5187 + 10,374), testing the hypothesis that the increase in the risk of subsequent atypical femur fractures exceeded the increase in typical hip fractures. We also sought evidence of a dose-response relationship, where high adherence to or long-term use of aln led to more atypical femur fractures. We found that 7% of patients with atypical fractures were aln exposed, and the same was found for typical hip fractures. In the cohort study, the HR for subtrochanteric/diaphyseal fracture with aln was 1.46 (0.91-2.35, p = 0.12) compared with 1.45 (1.21-1.74, p < 0.001) for hip fracture after adjustment for comorbidity and co-medications. The risk was reduced by high adherence, and the ratio between hip and subtrochanteric/diaphyseal femur fractures was identical in aln-treated patients and the control cohort even in the limited number of patients who received long-term treatment. Subtrochanteric/diaphyseal femur fractures share the epidemiology and treatment response of classical hip fractures and are best classified as osteoporotic fractures.
AB - Alendronate (aln) is a potent bisphosphonate with a prolonged duration of action. Recent reports have found long-term aln use to be common in patients with subtrochanteric or proximal diaphyseal femur fracture, raising concerns that these fractures could be a consequence of excessive suppression of bone turnover. Two national observational register-based studies were performed: (1) cross-sectional study (N = 11,944) comparing age distribution, exposure, and trauma mechanisms between different types of proximal femur fractures and (2) matched cohort study in patients with prior nonhip fractures (N = 5187 + 10,374), testing the hypothesis that the increase in the risk of subsequent atypical femur fractures exceeded the increase in typical hip fractures. We also sought evidence of a dose-response relationship, where high adherence to or long-term use of aln led to more atypical femur fractures. We found that 7% of patients with atypical fractures were aln exposed, and the same was found for typical hip fractures. In the cohort study, the HR for subtrochanteric/diaphyseal fracture with aln was 1.46 (0.91-2.35, p = 0.12) compared with 1.45 (1.21-1.74, p < 0.001) for hip fracture after adjustment for comorbidity and co-medications. The risk was reduced by high adherence, and the ratio between hip and subtrochanteric/diaphyseal femur fractures was identical in aln-treated patients and the control cohort even in the limited number of patients who received long-term treatment. Subtrochanteric/diaphyseal femur fractures share the epidemiology and treatment response of classical hip fractures and are best classified as osteoporotic fractures.
U2 - 10.1359/jbmr.081247
DO - 10.1359/jbmr.081247
M3 - Journal article
C2 - 19113931
SN - 0884-0431
VL - 24
SP - 1095
EP - 1102
JO - Journal of Bone and Mineral Research
JF - Journal of Bone and Mineral Research
IS - 6
ER -