[Chronic kidney disease - Mineral bone disorders: Physiopathology and guidelines]

Chronic Kidney Disease (CKD) is associated with a strong impact on phosphocalcic homeostasis, due to the chronic reduction in glomerular filtration rate (GFR) (phosphate excretion decrease), the inhibition of calcitriol synthesis and dietary restrictions. CKD-Mineral and Bone Disorders (CKD-MBD) must be monitored in CKD patients with biological work-up associated with bone markers and bone density dual X-ray absorptiometry. Adapted diet (phosphate restriction, normalization of calcium intake) and medications (vitamin D, phosphate binders, calcimimetics) help to correct CKD-MBD. Serum parathormone must be kept between 2 to 9 times the usual values, to limit renal osteodystrophy and avoid tertiary hyperparathyroidism. CKD patients are also at risk of artery calcifications, which can significantly increase the morbidity and mortality of the affection. Bisphosphonates may be used after correction of biological abnormalities, in patients with estimated GFR above 30ml/min/1,73m². Even if transplantation aims to normalize kidney function, kidney transplant recipients remain at risk of CKD-MBD. Biology and bone density dual X-ray absorptiometry must be regularly assessed, especially in the few months following the transplantation. More studies are needed to know if treatments of CKD-MBD are well tolerated in severe CKD and if they are associated with a decrease of bone fracture and vascular calcifications.