Osteoporosis International

, Volume 19, Issue 6, pp 811–818

Adherence to bisphosphonates therapy and hip fracture risk in osteoporotic women

  • V. Rabenda
  • R. Mertens
  • V. Fabri
  • J. Vanoverloop
  • F. Sumkay
  • C. Vannecke
  • A. Deswaef
  • G. A. Verpooten
  • J.-Y. Reginster
Original Article

DOI: 10.1007/s00198-007-0506-x

Cite this article as:
Rabenda, V., Mertens, R., Fabri, V. et al. Osteoporos Int (2008) 19: 811. doi:10.1007/s00198-007-0506-x

Abstract

Summary

Adherence is now one of the major issues in the management of osteoporosis and several papers have suggested that vertebral fractures might be increased in patients who do not follow appropriately their prescriptions. This paper relates the strong relationship existing between adherence to anti-osteoporosis treatment and the risk of subsequent hip fracture.

Introduction

A study was performed to investigate adherence to bisphosphonate (BP) therapy and the impact of adherence on the risk of hip fracture (Fx).

Methods

An exhaustive search of the Belgian national social security database was conducted. Patients enrolled in the study were postmenopausal women, naïve to BP, who received a first prescription of alendronate. Compliance at 12 months was quantified using the medication possession ratio (MPR). Persistence was calculated as the number of days from the initial prescription to a gap of more than 5 weeks after completion of the previous refill. A logistic regression model was used to estimate the impact of compliance on the risk of hip fracture. The impact of persistence on hip fracture risk was analysed using the Cox proportional hazards model.

Results

The mean MPR at 12 months was significantly higher among patients receiving weekly (n = 15.021) compared to daily alendronate (n = 14,136) (daily = 58.6%; weekly = 70.5%; p < 0.001). At 12 months, the rate of persistence was 39.45%. For each decrease of the MPR by 1%, the risk of hip Fx increased by 0.4% (OR: 0.996; CI95%:0.994–0.998; p < 0.001). The relative risk reduction for hip Fx was 60% (HR: 0.404;CI95%:0.357–0.457; p < 0.0001) for persistent compared to non-persistent patients.

Conclusion

These results confirm that adherence to current therapeutic regimens remains suboptimal.

Keywords

AdherenceBisphosphonatesHip fractureOsteoporosis

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2007

Authors and Affiliations

  • V. Rabenda
    • 1
    • 2
  • R. Mertens
    • 3
    • 4
  • V. Fabri
    • 4
    • 5
  • J. Vanoverloop
    • 4
    • 5
  • F. Sumkay
    • 3
  • C. Vannecke
    • 6
  • A. Deswaef
    • 6
  • G. A. Verpooten
    • 7
  • J.-Y. Reginster
    • 1
    • 2
  1. 1.WHO Collaborating Center for Public Health Aspects of Osteoarticular DisordersUniversity of LiègeLiègeBelgium
  2. 2.Department of Public Health, Epidemiology and Health EconomicsUniversity of LiègeLiègeBelgium
  3. 3.Alliance Nationale des Mutualités ChrétiennesBrusselsBelgium
  4. 4.Agence IntermutualisteBrusselsBelgium
  5. 5.Union nationale des Mutualités SocialistesBrusselsBelgium
  6. 6.Institut National d’Assurances Maladie InvaliditéBrusselsBelgium
  7. 7.Department of Nephrology-HypertensionAntwerp University HospitalsAntwerpBelgium