 OFC is a common presentation of renal osteodystrophy , which is a term used to refer to the skeletal complications of end stage renal disease ( ESRD ) . OFC occurs in approximately 50 % of patients with ESRD . ESRD occurs when the kidneys fail to produce calcitriol , a form of Vitamin D , which assists in the absorption of calcium into the bones . When calcitriol levels decrease , parathyroid hormone levels increase , halting the storage of calcium , and instead triggering its removal from the bones . The concept of renal osteodystrophy is currently included into the broader term chronic kidney disease @-@ mineral and bone disorder ( CKD @-@ MBD ) . 
