Association Between Renal Function and Fracture Incidence During Treatment with Teriparatide or Alendronate: an Exploratory Subgroup Analysis of the Japanese Osteoporosis Intervention Trial-05
Overview
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Purpose: Incidence rate of morphometric vertebral fracture was lower under treatment with once-weekly teriparatide (TPTD) followed by alendronate (ALN) than under treatment with ALN throughout the study among elderly Japanese women at high fracture risk in JOINT-05. This is an exploratory subgroup analysis according to chronic kidney disease (CKD) status at baseline.
Methods: Participants received sequential therapy with TPTD for 72 weeks, followed by ALN for 48 weeks (TPTD-ALN group, N = 483) or ALN monotherapy for 120 weeks (ALN group, N = 496). Baseline CKD status was classified by the estimated glomerular filtration rate (eGFR) and categorized as: CKD 1/2 (eGFR ≥ 60 mL/min/1.73 m), CKD 3a (eGFR 45-59 mL/min/1.73 m), or CKD 3b/4 (eGFR < 45 mL/min/1.73 m). Incidences of vertebral fractures including morphometric fractures, non-vertebral fractures, and all fractures were evaluated during follow-up.
Results: Baseline characteristics were not different between treatment groups. Higher stages of CKD were associated with age and number of prevalent vertebral fracture. In CKD 1/2 patients (N = 556 with 90 incidents of morphometric vertebral fracture), the incidence of vertebral fractures was lower in the TPTD-ALN group than in the ALN group (p = 0.01). In CKD 3b/4 patients (N = 112 with 10 incidents of non-vertebral fracture), the incidence of non-vertebral fractures was lower in the ALN group than in the TPTD-ALN group, although the number of fractures was small. In the ALN group, the incidences of vertebral fractures, non-vertebral fractures, and all fractures remained constant across CKD stages.
Conclusion: This exploratory analysis showed that fracture incidence on ALN was constant regardless of renal function. It also suggested that the incidence of vertebral fractures on TPTD-ALN was lower than ALN monotherapy in CKD 1/2 patients. These results provide important information for drug selection in the clinical practice of osteoporosis.