Observational Study Emulation: Denosumab vs. Oral Bisphosphonates in Dialysis-Dependent Patients Shows Reduced Fractures but Possible Elevated Cardiovascular Risk

Background: Patients receiving dialysis have a markedly increased risk of osteoporotic fractures, yet management options in this population remain challenging. Although oral bisphosphonates are the usual first-line treatment for osteoporosis, safety concerns exist for those with severe chronic kidney disease (CKD). Denosumab, which is not cleared via the kidney, offers a potential alternative, but limited data compare its fracture-prevention benefit and cardiovascular (CV) safety against bisphosphonates in dialysis-dependent patients.

Objective: To estimate the risk for major adverse cardiac events (MACE) and the effectiveness in preventing fractures when using denosumab compared with oral bisphosphonates among patients undergoing dialysis.

Methods: This study emulated a target trial using an observational Japanese administrative claims database (April 2014 to October 2022). Adults aged 50 years or older, receiving dialysis and newly prescribed denosumab (60 mg subcutaneously) or oral bisphosphonates (alendronate, risedronate, ibandronate, or minodronate) were included. Exclusions involved recent acute myocardial infarction, stroke, or heart failure. Inverse probability of treatment weighting (IPTW) based on propensity scores was used to balance baseline characteristics. The primary safety outcome was MACE (acute myocardial infarction, stroke, hospitalization for heart failure, or CV death), and the primary effectiveness outcome was all fractures. Three-year risks, risk differences, and risk ratios were estimated.

Results: Among 658 denosumab users and 374 oral bisphosphonate users (mean age, 74.5 years; 62.9% women) followed for up to 3 years, denosumab was associated with a higher weighted risk of MACE (3-year risk ratio, 1.36 [95% CI, 0.99 to 1.87]; risk difference, 8.2% [–0.2% to 16.7%]) compared with oral bisphosphonates. Although the point estimate suggests a notable increase, the 95% CI includes 1.0, indicating that statistical significance was not definitively achieved. Denosumab showed a significantly lower composite fracture risk (3-year risk ratio, 0.55 [0.28 to 0.93]; risk difference, –5.3% [–11.3% to –0.6%]). Individual fracture sites (e.g., hip, vertebral) had imprecise estimates but trended toward fewer nonvertebral fractures with denosumab. Mortality rates did not differ substantially between the groups.

Conclusions: In dialysis-dependent patients with osteoporosis, denosumab may reduce fracture risk while potentially elevating the likelihood of MACE. However, the higher MACE estimate did not surpass the conventional threshold for statistical significance, warranting cautious interpretation. Although these data suggest a clinically meaningful reduction in fractures, the findings regarding cardiovascular outcomes remain imprecise and require further confirmation.

Implications for Practice: Clinicians treating dialysis-dependent patients should weigh denosumab’s fracture-prevention advantage against its possible heightened CV risk. Oral bisphosphonates, though sometimes restricted in severe CKD, may confer lower risk of MACE. Careful monitoring of electrolyte levels, especially calcium, and CV status is essential when administering denosumab in end-stage kidney disease.

Study Strengths and Limitations: Strengths include a large, real-world cohort and the use of target trial emulation with robust propensity score weighting. Limitations involve potential residual confounding, reliance on claims-based definitions of outcomes, and absent lab data (e.g., serum calcium, glomerular filtration rate). Consequently, causality and generalizability should be interpreted with caution, especially outside Japan.

Future Research:
Prospective trials and additional observational studies using detailed clinical data (including renal function parameters and bone mineral density) are needed to clarify the relative net benefits of denosumab versus bisphosphonates in advanced CKD. Investigations into other safety outcomes, such as long-term renal function and hypocalcemia-related complications, would further inform clinical decision-making.

Reference: Masuda S, Fukasawa T, Matsuda S, Kawakami K. “Cardiovascular Safety and Fracture Prevention Effectiveness of Denosumab Versus Oral Bisphosphonates in Patients Receiving Dialysis: A Target Trial Emulation.” Annals of Internal Medicine. DOI:
https://doi.org/10.7326/ANNALS-24-03237