E-Poster Presentation ESA-SRB-ANZBMS 2021

Comparison of Fracture Rates and Economic Outcomes Between Women with Osteoporosis Receiving Risedronate Enteric-Coated and Alendronate (#37)

Friederike Thomasius 1 , Santiago Palacios 2 , Asif Alam 3 , Mitra Boolell 3 , Rachel L Duckham 4 , Francis Vekeman 5 , Genevieve Gauthier 5
  1. Frankfurter Hormon und Osteoporosezentrum, , Frankfurt, Germany
  2. Palacios’ Institute of Women’s Health, Madrid, Spain
  3. Theramex, , London, United Kingdom
  4. Theramex, Sydney, NSW, Australia
  5. STATLOG, Montreal, Canada

Objective: Risedronate Enteric-Coated (EC) offers a convenient dosing option eliminating the need for fasting, while providing a higher bioavailability of the medication when compared to immediate-release risedronate (Risedronate EC SmPC). However, the benefit of this dosing to reduce risk of fracture compared to other oral bisphosphonates such as alendronate remains unknown. Thus, the aim of this study was to compare the risk of fractures and economic outcomes between women with osteoporosis receiving risedronate EC vs. alendronate immediate-release.

Methods: Women with osteoporosis were identified from a US claims database (2009-2019) and observed for ≥2 years following the date of their first observed dispensing for an oral bisphosphonate (index date). Women were classified into the risedronate EC or alendronate cohort based on the treatment-initiated index date. The cohorts were matched 1:1 based on demographic and clinical characteristics evaluated during a six-month period prior to the index date. Incidence rates (IRs) of fractures and healthcare resource utilization per 1,000 patient-years were compared between the two cohorts using IR ratios (IRRs). Alpha level set as P<0.05.

Results: 1,807 patients were selected in each cohort (median age: 60.0 years; average observation period [years]: risedronate EC: 4.3, alendronate: 4.6). The IR of fractures was significantly lower in the risedronate EC vs the alendronate cohort for any fracture site (IRR: 0.81, 29%, reduction, p<0.05) and spine fractures (IRR: 0.69, 31%, reduction p<0.05) (table-1). Compared to the alendronate cohort, the risedronate EC cohort incurred fewer hospitalizations (IR, EC: 112.03; alendronate: 134.69; IRR: 0.85, p<0.05) translating into numerically lower hospitalization costs (average per-patient-per-year; EC: $3,605; alendronate: $4,572, p=0.07).

Conclusion: Findings indicate that women treated with risedronate EC have a lower incidence of fractures compared to those treated with alendronate, consistent with the hypothesis that the enteric-coated formulation of risedronate (35mg once weekly) improves medication absorption, enabling  greater effectiveness.

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