Accelerated bone loss increases osteoporosis and fracture risk in moderate to severe chronic kidney disease

Chronic kidney disease-mineral and bone disorder (CKD-MBD) contributes to bone loss and fractures. Evidence on longitudinal changes in bone mineral density (BMD) in CKD remains limited. This retrospective cohort study evaluated the longitudinal decline in BMD across levels of kidney function and examined the associations between kidney function and the risk of osteoporosis and fractures. Patients with estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² who underwent dual-energy X-ray absorptiometry between 2010 and 2023 were included. Associations between kidney function, longitudinal BMD changes, and a composite outcome of new-onset osteoporosis or incident fracture were analyzed. A total of 2,909 patients had BMD measurements at the total hip (TH) and femoral neck (FN), and 2,596 at the lumbar spine (LS). At baseline, over 90% had an eGFR of 30-59 mL/min/1.73 m². Lower eGFR was associated with reduced TH BMD and, to a lesser extent, FN BMD, while LS BMD showed no consistent decline. An eGFR <45 mL/min/1.73 m² was an independent risk factor for lower TH and FN BMD. Among 1,301 patients with serial measurements (median follow-up 4.5 years), declines in TH and FN BMD and T-scores were observed, with greater loss in the eGFR <45 mL/min/1.73 m² group. Lower BMD at all sites and eGFR <45 mL/min/1.73 m² were independent risk factors of the composite outcome. In conclusion, declining kidney function is associated with accelerated bone loss and increased risk of osteoporosis and fractures, underscoring the importance of BMD monitoring in patients with moderate to severe CKD.