Sparing effect of peritoneal dialysis vs hemodialysis on BMD changes and its impact on mortality

Introduction Bone loss in end stage renal disease (ESRD) patients associates with fractures, vascular calcification, cardiovascular disease (CVD) and increased mortality. We investigated factors associated with changes of bone mineral density (Delta BMD) during the initial year on dialysis therapy and associations of Delta BMD with subsequent mortality in ESRD patients initiating dialysis. Materials and methods In 242 ESRD patients (median age 55 years, 61% men) starting dialysis with peritoneal dialysis (PD;n = 138) or hemodialysis (HD;n = 104), whole-body dual-energy X-ray absorptiometry (DXA), body composition, nutritional status and circulating biomarkers were assessed at baseline and 1 year after dialysis start. We used multivariate linear regression analysis to determine factors associated with Delta BMD, and fine and gray competing risk analysis to determine associations of Delta BMD with subsequent mortality risk. Results BMD decreased significantly in HD patients (significant reductions of BMD(total)and BMDleg, trunk, rib, pelvis and spine) but not in PD patients. HD compared to PD therapy associated with negative changes in BMDtotal (beta=- 0.15), BMDhead (beta=- 0.14), BMD(leg (beta=- 0.18))and BMDtrunk (beta=- 0.16). Better preservation of BMD associated with significantly lower all-cause mortality for Delta BMDtotal(sub-hazard ratio, sHR, 0.91), Delta BMDhead(sHR 0.91) and Delta BMDleg(sHR 0.92), while only Delta BMDhead(sHR 0.92) had a beneficial effect on CVD-mortality. Conclusions PD had beneficial effect compared with HD on BMD changes during first year of dialysis therapy. Better preservation of BMD, especially in bone sites rich in cortical bone, associated with lower subsequent mortality. BMD in cortical bone may have stronger association with clinical outcome than BMD in trabecular bone.

Automated summary

In ESRD patients initiating dialysis, bone density changes during the first year were better preserved with peritoneal dialysis (PD) compared to hemodialysis (HD), and better preservation of bone density, especially in cortical bone, was associated with lower subsequent mortality. Bones rich in cortical bone may have a stronger association with clinical outcomes compared to bones rich in trabecular bone.