Bone mineral density at different sites and 5 years mortality in end-stage renal disease patients: A cohort study

Background: Bone disease with osteoporosis and renal osteodystrophy is common in end stage renal disease (ESRD) patients and associates with cardiovascular disease (CVD) and increased morbimortality. We investigated associations of low bone mineral density (BMD) at various bone sites with five year all-cause and CVD mortality in ESRD patients. Methods: In a post hoc analysis of 426 ESRD patients (median age 56 years, 62% men) starting dialysis, BMD (whole-body dual-energy X-ray absorptiometry, DXA), body composition, nutritional status (subjective global assessment, SGA), handgrip strength (%HGS), Framingham CVD risk score (FRS) and biochemical biomarkers of nutrition and inflammation were assessed. We used the Fine and Gray competing risk regression analysis to assess survival analysis. Results: In multivariate logistic regression analysis, %HGS and intact parathyroid hormone associated with low tertile of: BMDtotal, BMDhead and BMDpelvis, after adjusting for FRS, SGA, %HGS, s-albumin, hsCRP, lean body mass index and year of recruitment. Patients with high FRS had low BMDhead (p < 0.001). Low tertile of BMDtotal (sHR, 1.53), BMDhead (sHR 1.54) and BMDpelvis (sHR 1.60) associated with increased all-cause mortality whereas no such associations were found for the trabecular bone rich sites BMD arm, leg, trunk, rib or spine. Low tertile of BMDtotal (sHR 1.94), BMDhead (sHR 1.68), BMDleg (sHR 2.25) and BMDpelvis (sHR 2.45) associated with increased CVD mortality whereas BMD at other sites did not associate with CVD mortality. Conclusion: Low head and pelvis BMD, and low total BMD, as assessed by whole-body DXA, were independent predictors of increased risk of all-cause and CVD mortality. Cortical BMD appeared to have stronger association to survival in ESRD than trabecular BMD.