Total hip bone mass predicts survival in chronic hemodialysis patients

Bone mass measurements are widely used to diagnose osteoporosis and identify patients at risk for fractures. Recent studies have shown that reduced bone mass is also predictive of all-cause and cardiovascular mortality in healthy postmenopausal women. Among chronic hemodialysis patients reduced bone mass resulting from the combined effects of age-related factors and renal osteodystrophy has been associated with vascular calcification. In this prospective study, we investigated the ability of bone mass measurements to predict mortality in chronic hemodialysis patients.

Eighty eight patients underwent hip bone mass measurements by dual energy x-ray absorptiometry (DEXA) and were followed up for a mean of 3.5 years. Eleven patients received renal transplants and were therefore excluded. Forty of the remaining patients died, predominantly due to cardiovascular causes (43%).

Cox regression analysis showed patient age, osteoporosis or osteopenia, and baseline average calcium x phosphate product (Ca x P) to be independently predictive of increased mortality. Patients with osteopenia or osteoporosis had a 3.3- and 4.3-fold increased risk of death, respectively. A Ca x P of >or=5.0 mmol2/L2 predicted a threefold increased risk of death. Previous renal transplantation predicted a lower mortality.

This study has shown for the first time that reduced total hip bone mass is an independent predictor of all-cause mortality among chronic hemodialysis patients. Our findings suggest that reduced bone mass and elevated Ca x P may be involved in the pathogenesis of cardiovascular disease in these patients but further research is required to investigate the possible mechanisms for these associations.