30th ASBMR 2008
[M367] Fracture Risk in Women Aged 65 Years or Older With Once-Monthly Oral Ibandronate Compared With Weekly Bisphosphonates: Analyses From the eValuation of IBandronate Efficacy (VIBE) Database Fracture Study
Stuart Silverman, William Blumentals, Sara Poston, Steven Harris.. Cedars-Sinai Medical Center/UCLA; Roche; GlaxoSmithKline; University of California, San Francisco.
The VIBE study compared fracture risk between patients treated with once-monthly and weekly oral bisphosphonates (BPs). This subanalysis focused on a higher-risk group of older women, aged ≥65 years.
Patients were newly prescribed once-monthly oral ibandronate or weekly oral alendronate or risedronate, adherent for ≥90 days, and without malignancy or Paget’s disease. Data were censored at fracture, 12 months after BP initiation, end of health plan enrollment, BP brand switch, regimen switch, or treatment discontinuation. Fracture risk was compared using Cox regression models to calculate hazard ratio (HR) and adjusted for potential confounding factors (age, concomitant medications, estrogen use, outpatient visits, osteoporosis diagnosis, bone densitometry procedure, fracture history, glucocorticoid use, use of other non-estrogen osteoporosis medications). The analysis was repeated for the separate weekly alendronate or risedronate groups compared with ibandronate.
The analysis included 1,811 patients receiving once-monthly ibandronate and 14,648 patients receiving weekly BPs (alendronate 9,270, risedronate 5,378). Baseline characteristics included: mean (median) age 72.41 (72) years for ibandronate vs 72.82 (73) years for weekly BPs (p=0.0029); pre-index fracture 6.29% for ibandronate vs 6.45% for weekly BPs (p=0.7979); pre-index glucocorticoid use 15.52% for ibandronate vs 10.98% for weekly BPs (p<0.001); pre-index rheumatoid arthritis diagnosis 5.36% for ibandronate vs 3.29% for weekly BPs (p<0.001). The risks of hip fracture, and nonvertebral fracture (NVF) were not significantly different between groups (hip fracture adjusted HR 1.14, p=0.707; NVF 0.75, p=0.172), but the risks of vertebral fracture and all fractures were statistically lower in the ibandronate group (vertebral fracture adjusted HR 0.28, p=0.030; all fractures 0.65, p=0.033). Similarly, when comparing ibandronate vs individual weekly BPs, the risk of hip fracture or NVF was not significantly different from either alendronate or risedronate.
Women aged ≥65 years treated with oral once-monthly ibandronate or weekly BPs had similar risks of hip fracture or NVF. The risks of vertebral fracture and all fractures were statistically lower for ibandronate patients, though the clinical implications of these findings require further exploration and validation.
S.L. Silverman, Eli Lilly, Novartis, Merck, Procter & Gamble, Roche, Inc., Wyeth 3; Eli Lilly, Merck, Procter & Gamble, Roche 2; Merck, Novartis, Roche, Wyeth 1.
Roche and GlaxoSmithKline
Date: Monday, September 15, 2008
Session Info: Poster: Osteoporosis Treatment (Clinical): Bisphosphonates (11:30 AM-2:30 PM)
Presentation Time: 11:30 AM