Diagnostic usefulness of bone mineral density and biochemical markers of bone turnover in predicting fracture in CKD stage 5D patients--a single-center cohort study.

Background: In chronic kidney disease stage 5D, diagnostic usefulness of bone mineral density (BMD) in predicting fracture has not been established because of variable results in previous studies. The reason for this may be the heterogeneity of underlying pathogenesis of the fracture.

Methods: BMD was measured annually and serum biochemistry monthly for 485 hemodialyzed patients from April 2003 to March 2008, and all fractures were recorded.

Results: Forty-six new episodes of any type of fracture and 29 cases of prevalent spine fracture were recorded. Serum bone-specific alkaline phosphatase (b-AP) was a very useful surrogate marker for any type of incident fracture risk [area under curve (AUC) = 0.766, P < 0.0001]. A significantly greater risk of any type of incident fracture was associated with parathyroid hormone (PTH) levels either <150 pg/mL [hazard ratio (HR) = 3.47, P < 0.01] or >300 pg/mL (HR = 5.88, P < 0.0001) compared with 150-300 pg/mL. Receiver-operating characteristic analysis demonstrated a significant predictive power for incident of any type of fracture by BMD at the total hip (AUC = 0.760, P < 0.0001) and other hip regions in females in the lower PTH group (PTH < 204 pg/mL). BMDs at every site but whole body or lumbar spine had significant power to discriminate prevalent spine fracture regardless of gender or PTH.

Conclusions: Hemodialyzed patients with low or high PTH or increased b-AP had a high fracture risk. BMD by Dual Energy X-ray Absorptiometry (DEXA), especially at the total hip region, was useful to predict any type of incident of fracture for females with low PTH or to discriminate prevalent spine fracture for every patient.