Renal Osteodystrophy in Peritoneal Dialysis: Special Considerations

Abstract

Bone disease is one of the most challenging complications in patients with chronic kidney disease. Today, it is considered to be part of a complex systemic disorder manifested by disturbances of mineral metabolism and vascular calcifications called chronic kidney disease – mineral bone disorder (CKD-MBD). The term renal osteodystrophy is reserved to define the specific bone lesion in CKD-MBD, whose spectrum ranges from high turnover to low turnover disease. Phosphate retention, decreased serum calcium, and 1,25-dihydroxy vitamin D synthesis are involved in the pathogenesis of high bone turnover. However, the various therapeutic approaches (calcium supplements, phosphate binders, and vitamin D metabolites, among others), the renal replacement modality (hemodialysis or continuous ambulatory peritoneal dialysis), and the types of patients to whom dialysis is offered (more patients who are diabetic or older, or both) may influence the evolution of the bone disorder. As a result, recent studies have reported a greater prevalence of adynamic forms of renal osteodystrophy, especially in diabetic and peritoneal dialysis patients. The present article reviews, for patients treated with peritoneal dialysis, the pathophysiologic mechanisms involved in the evolution and perpetuation of this bone disease and the therapeutic modalities for treating and preventing adynamic bone.

Association Between Blood Cadmium Levels and Mortality in Peritoneal Dialysis

“… 17 Our data showed that the relationship between BCL and low turnover bone disease persisted even after adjusting for factors previously described as confounders. 34 These data were in agreement with a previous study which showed a significant inverse association between serum PTH and BCLs. 35 The mechanism underlying this association is thought to be mediated by increased osteoclast bone resorption, which mobilizes more calcium from skeletal to the circulation.…”

“… 3 Critically, accumulating evidence indicated that either low turnover bone disease or higher calcium load to the circulation may contribute substantially to increased death risk in dialysis patients. 34 , 36 Moreover, low turnover bone disease in dialysis patients has been implied to be a consequence of the malnutrition–inflammation complex syndrome, 37 providing further support to our first hypothesis.…”

Biomarkers Associated with Vascular Calcification in Peritoneal Dialysis

“…Patients on PD may have different mineral metabolism disorders than patients on hemodialysis, including a higher frequency of adynamic bone disease (4) or a reduced risk of cardiac valve calcification over time, probably related to the higher prevalence of residual renal function (RRF) (5). Observational studies of small numbers of patients on PD have described a prevalence of vascular calcification in the range of 32 -60% (6)(7)(8).…”

New peritoneal dialysates, for which benefits ?

“…En ce qui concerne le magnésium, une concentration dans le dialysat de 0,25 mmol/l conduit à une extraction péritonéale de l'ordre de 0,5 à 1 mmol/l, soit une valeur également proche de l'élimination urinaire quotidienne. L'ostéodystrophie rénale du patient en DP est marquée par une très forte prévalence de l'ostéopathie adynamique (près de 50%) (tableau II) (15). La prévention de cette complication nécessite d'éviter le recours aux solutions de dialyse à concentration élevée de calcium (> 1,25 mmol/l), et de limiter l'apport oral de calcium à moins de 1,5 g/jour de calcium-élément.…”