Fracture risk after kidney transplantation: unchanged and unaddressed: a registry-based cohort study across two decades

BACKGROUND: Kidney transplant recipients face a high risk of adverse events, including fractures. Reported fracture rates post-transplant vary widely and may have changed over time. The consequences of a fracture, especially subsequent fractures, remain under-investigated. This study examined the risk and prognosis of fractures after kidney transplantation in the current era.

METHODS: This retrospective cohort study included all adults who received a first single-organ kidney transplant between 2000 and 2022 in Denmark. Nationwide healthcare registries were utilized to identify the study population and provide demographic data, diagnostic and procedural codes, and prescription data. Cumulative incidence (risk) of both first fracture and subsequent fracture was computed, treating death as a competing risk. Crude, and sex- and age-standardized incidence rates were estimated for different time periods.

RESULTS: The study included 3977 first kidney transplant recipients, of whom 788 sustained any post-transplant fracture. The 10-year risk of fracture was 21% (95% confidence interval 20-23). Crude incidence rates of any fracture remained unchanged over time, while standardized estimates showed a slight decline. Fractures were primarily located at the peripheral skeleton. Twenty-eight percent of patients with a fracture sustained a subsequent fracture, with the highest incidence at 6-12 months following the first event.

CONCLUSIONS: Kidney transplant recipients remain at high fracture risk, with unchanged fracture rates over the past 20 years. The imminent fracture risk following a first fracture is high and largely unaddressed. Although formal guidelines have yet to be established, this knowledge should urge clinicians to perform risk assessment and consider intervention following a post-transplant fracture.