Efficacy of continued alendronate for fractures in women with and without prevalent vertebral fracture: the FLEX trial.
In the Fracture Intervention Trial (FIT) Long Term Extension (FLEX) Trial, 10 years of alendronate (ALN) did not significantly reduce the risk of nonvertebral fractures (NVFs) compared with 5 years of ALN. Continuing ALN reduced the risk of clinical but not morphometric vertebral fractures regardless of baseline vertebral fracture status. In previous studies, ALN efficacy for NVF prevention in women without prevalent vertebral fracture was limited to those with femoral neck (FN) T-scores of -2.5 or less. To determine whether the effect of long-term ALN on fracture differs by vertebral fracture status and femoral neck (FN) T-score, we performed a post hoc analysis using FLEX data, a randomized, double-blind, placebo-controlled trial among 1099 postmenopausal women originally randomized to ALN in the FIT with mean ALN use of 5 years. In the FLEX Trial, women were randomized to placebo (40%) or ALN 5 mg/day (30%) or ALN 10 mg/day (30%) for an additional 5 years. Among women without vertebral fracture at FLEX baseline (n = 720), continuation of ALN reduced NVF in women with FLEX baseline FN T-scores of -2.5 or less [relative risk (RR) = 0.50, 95% confidence interval (CI) 0.26-0.96] but not with T-scores of greater than -2.5 and -2 or less (RR 0.79, 95% CI 0.37-1.66) or with T-scores of greater than -2 (RR 1.41, 95% CI 0.75-2.66; p for interaction = .019). Continuing ALN for 10 years instead of stopping after 5 years reduces NVF risk in women without prevalent vertebral fracture whose FN T-scores, achieved after 5 years of ALN, are -2.5 or less but does not reduce risk of NVF in women whose T-scores are greater than -2.
Schwartz
Ann V
AV
Department of Epidemiology and Biostatistics, University of California-San Francisco, San Francisco, CA, USA. aschwartz@psg.ucsf.edu
Bauer
Douglas C
DC
Cummings
Steven R
SR
Cauley
Jane A
JA
Ensrud
Kristine E
KE
Palermo
Lisa
L
Wallace
Robert B
RB
Hochberg
Marc C
MC
Feldstein
Adrianne C
AC
Lombardi
Antonio
A
Black
Dennis M
DM
D000368:Aged; D000369:Aged, 80 and over; D019386:Alendronate / Q000008:administration & dosage*; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D005272:Femur Neck; D050723:Fractures, Bone / Q000517:prevention & control*; D006801:Humans; D008875:Middle Aged; D016103:Spinal Fractures / Q000517:prevention & control*; D016896:Treatment Outcome
D050071:Bone Density Conservation Agents; D019386:Alendronate