Objective: Compare the efficacy of bazedoxifene with oral bisphosphonates for reduction of vertebral fracture risk in postmenopausal osteoporotic (PMO) women and in higher-risk patients based on evidence from randomized controlled trials (RCTs).
Methods: Eight RCTs assessing vertebral fracture risk reduction with oral bisphosphonates (n = 7) or bazedoxifene (n = 1) were identified by a systematic literature review. Individual study results were pooled in a network meta-analysis (NMA) to indirectly compare treatment effects for overall PMO women and a higher-risk subgroup (FRAX ≥ 20%). Three sets of NMA analyses were conducted: aggregate data (AD) from the bisphosphonate RCTs and bazedoxifene RCT for the full population or the FRAX ≥20% subgroup (NMA AD); bisphosphonate AD and bazedoxifene AD from each FRAX subgroup adjusted for baseline risk (NMA AD meta-regression); and bisphosphonate AD and bazedoxifene individual patient data (IPD) adjusted for baseline risk/FRAX (NMA AD/IPD meta-regression).
Results: For the overall population, bisphosphonates had lower fracture risks versus bazedoxifene although there is considerable uncertainty in supporting one intervention over another. The relative risk reduction (RRR) for bazedoxifene was -0.23 (95% CrI: -1.11, 0.27) versus ibandronate, -0.17 (-0.76, 0.22) versus alendronate, and -0.06 (-0.62, 0.30) versus risedronate. RESULTS from the meta-regression analyses were similar. For the FRAX ≥20% population, estimated fracture rates with bazedoxifene were lower than with bisphosphonates, but again the uncertainty limits strong interpretation. The RRR for bazedoxifene was 0.51 (-0.31, 0.83) versus ibandronate, 0.53 (-0.18, 0.83) versus alendronate, and 0.57 (-0.07, 0.85) versus risedronate. The meta-regression analyses showed comparable findings.
Conclusion: The analyses only considered vertebral fractures for oral bisphosphonates versus bazedoxifene, and IPD was available only for bazedoxifene. In light of this, bazedoxifene is comparable to bisphosphonates in the overall PMO population and at least as effective as bisphosphonates for preventing vertebral fractures among higher-risk PMO patients. The findings suggest bazedoxifene performs better in higher-risk PMO than in the overall PMO.
Keywords: Bazedoxifene; Bisphosphonates; Fractures; Indirect comparison; Osteoporosis.