Femoral Neck X-Ray Absorptiometry Parameters and Peripheral Quantitative Computer Tomography Tibial Cortical Density Predict Survival in Dialysis Patients.
BACKGROUND
Low bone mineral density (BMD) is a known independent predictor of mortality in the general elderly population. However, studies in patients with end-stage renal disease (ESRD) are limited. The present study evaluated mortality during long-term follow-up in a population of patients having dialysis for ESRD, in whom BMD was also measured.


METHODS
Fifty-eight patients with ESRD were recruited consecutively from a dialysis clinic and followed prospectively for 6 years. Baseline BMD of the lumbar spine and femoral neck (FN) were measured by X-ray absorptiometry and by peripheral quantitative CT at the radius and tibia. Serum calcium, phosphate, parathyroid hormone (PTH), and albumin were measured at baseline.


RESULTS
During follow-up, 25 patients died. Univariate analysis showed that mortality was significantly associated with FN-BMD: hazards ratio (HR) per 0.1 g/cm2 decrease 1.50 (95% CI 1.07-2.10), p = 0.019; FN-T score: HR per 1-SD decrease 1.84 (95% CI 1.16-2.92), p = 0.009; and tibial cortical density: HR per 10 mg/cm3 decrease 1.08 (95% CI 1.02-1.14), p = 0.010. In multivariate analysis with stepwise adjustment for age, sex, transplant status, albumin, PTH, phosphate, dialysis duration, diabetes, and smoking, FN-T score remained significantly associated with mortality: HR per 1-SD decrease 1.82 (95% CI 1.02-3.24), p = 0.044, whereas the HR for FN-BMD and tibial cortical density were no longer significant. When 4 patients who had peritoneal dialysis were excluded, the HR relating FN-BMD, FN-T score, and tibial cortical density to mortality remained significant but became insignificant when albumin was included in the multivariate analysis.


CONCLUSIONS
Reduced FN-BMD, FN-T score, and tibial cortical density were significantly associated with an increased risk of death in patients with ESRD.
Department of Endocrinology, Royal North Shore Hospital, St Leonards, NSW, Australia.
Natalie
N
Yap
Phillip
P
Wong
Stella
S
McGinn
Maria-Liza
ML
Nery
Jean
J
Doyle
Lynda
L
Wells
Phillip
P
Clifton-Bligh
Roderick J
RJ
Clifton-Bligh
D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000368:Aged; D015519:Bone Density; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D016019:Survival Analysis; D013977:Tibia / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
Bone quantitative computer tomography; Chronic kidney disease-mineral and bone disorder; Dialysis; Mortality; Osteoporosis; X-ray absorptiometry