Progressive Decline in Hip Bone Mineral Density in Later Stages of CKD

Background: CKD-MBD leads to bone loss and fractures. Historically, BMD assessment was not recommended in CKD due to perceived limitations in reflecting bone quality. However, recent studies have demonstrated the prognostic value of BMD, leading to its recommendation in the KDIGO 2017 guidelines. Methods: All CKD 3-5D patients who underwent BMD testing between 2010 and 2023 were included. Patients with a prior history of osteoporosis or whose first BMD result met the WHO classification of osteoporosis were excluded. The study analyzed the association between BMD and baseline biochemical factors, the rate of BMD decline across different CKD stages, and the relationship with the composite outcome of osteoporosis and fractures. Results: A total of 2,909 CKD patients were included. As CKD advanced, total hip BMD and T-scores declined, and the prevalence of osteopenia increased significantly. Similarly, lower femoral neck T-scores were observed in CKD stages 4–5D compared to stage 3a. These trends were consistent in both males and females. No association was found between lumbar spine BMD decline and advancing CKD stage. In multivariate linear regression analysis using CKD stage 3a as the reference, stages 4–5D were independently associated with lower BMD and T-scores, and a higher prevalence of osteopenia at the total hip and femoral neck. In a subgroup of 1,301 patients with at least two BMD tests over a median follow-up of 5 years, a more pronounced decline in BMD was observed in stages 3b–5D compared to stage 3a. Lower baseline BMD and T-scores, along with a higher prevalence of osteopenia at the total hip, femoral neck, and lumbar spine, were independent predictors of the composite outcome of osteoporosis and fracture. Conclusion: Advancing CKD stage was associated with lower BMD and a greater rate of decline at the total hip and femoral neck. Reduced BMD was a significant predictor of the combined outcome of osteoporosis and fractures.