Chronic kidney disease-mineral and bone disorder
The kidneys play a critical role in maintaining normal serum calcium and phosphorus concentrations, under the regulation of three main hormones: parathyroid hormone, calcitriol, and fibroblast growth factor 23. With the progression of chronic kidney disease (CKD), most patients develop CKD–mineral and bone disorder (CKD-MBD), which is a systemic disorder involving derangement in mineral metabolism, renal osteodystrophy, and extraskeletal calcification. Disturbances in mineral metabolism develop early in CKD and include phosphate retention, hypocalcaemia, vitamin D deficiency, and hyperparathyroidism. Renal osteodystrophy involves pathologic changes of bone morphology related to progressive CKD and is quantifiable by histomorphometry, based on bone biopsy. CKD-MBD is associated with significant morbidity, including bone loss, fractures, cardiovascular disease, immune suppression, as well as increased mortality. As the disorder begins early in the course of CKD, a proactive approach with intervention is important. Therapeutic strategies could then be employed to prevent and correct these disturbances, aiming to improve cardiovascular outcomes and survival. Current practice guidelines for CKD-MBD are based on insufficient data and high-quality studies are required before specific treatment can be advocated strongly.