Re - understanding of CKD - related Mineral and Bone Metabolic Disorders

CKD, especially in maintenance hemodialysis patients often accompanied by calcium, phosphorus and other electrolyte abnormalities and bone metabolic disorders, formerly known as renal bone disease (ROD) or renal osteodystrophy. In 2005, the Global Radiation Prognosis Organization (KDIGO) suggested that the concept be extended to CKD-related minerals and bone metabolic disorders (CKD-MBD), a systemic or systemic disease, whereas ROD specifically refers to bone morphology Performance, is in the quantitative determination of bone transformation, mineralization and bone capacity on the basis of CKD bone lesions made pathological diagnosis. According to the state of bone dynamics, ROD can be pided into high conversion, low conversion and mixed bone disease.

High conversion of bone disease

Re - understanding of CKD - related Mineral and Bone Metabolic Disorders

Also known as hyperparathyroidism bone disease, mainly caused by high blood phosphorus and 1,25 (OH) 2D3 caused by SHPT. High PTH can not only cause fractures and bone deformities, but also increase the abnormal metabolism of calcium and phosphorus, causing skin itching, anemia, nerve damage and cardiovascular disease. Studies have shown that the incidence of serum calcium, phosphorus and PTH in patients with CKD increases with renal injury, and high PTH significantly increases the risk of death, hospitalization and fracture. Manuel observed in 16173 hematopoietic patients in Latin America and found that blood phosphorus, calcium and PTH levels and dialysis patients with all-cause mortality was "U" curve, that is higher or lower than the normal range of phosphorus, calcium and PTH will increase the mortality of dialysis patients. A meta-analysis published last year further showed that the increase in mortality was 1 mg / dl and the mortality rate increased by 18%.

At present, dialysis patients calcium, phosphorus, PTH compliance is not ideal. In 2005, statistics from several Western countries showed that the rate of calcium and phosphorus was 56%, PTH was only 23%, and the incidence of hyperphosphatemia was> 50%. Markett and other 22937 cases of hemodialysis patients in the United States were followed up for 2 years, found that blood phosphorus compliance rate of less than 50%, PTH compliance rate is lower, and bone metabolism related indicators less standard, the shorter the standard time, the higher the risk of death. China's hemodialysis patients with calcium, phosphorus, PTH compliance rate is not ideal, in 2010 Beijing hemodialysis patients with calcium, phosphorus, PTH compliance rates were 55%, 37.4% and 23.6%, 3 were the standard only 8.8 %.

In 2009, KDIGO updated the relevant guideline according to the latest evidence of evidence-based medicine, and put forward the new control standard of bone metabolism related indicators in CKD5 patients: 0.8 ~ 1.45 mmol / L, which is more stringent than the previous standard; Is 2.10 ~ 2.63 mmol / L; PTH is 2 ~ 9 times the normal level (about 100 ~ 600 pg / ml).

Low conversion and no dynamic bone disease

In recent years, with the enhanced use of SHPT and the wide application of active vitamin D, the incidence of high-conversion bone disease has gradually decreased, and the incidence of low-conversion bone disease is gradually increasing trend, especially without power The incidence of bone disease increased year by year, the incidence rate and the high conversion of bone disease was essentially flat.

Analysis of the reasons, no dynamic bone disease and dialysis treatment in a large number of calcium-containing phosphorus adsorbent, high calcium dialysate caused by excessive calcium intake, active vitamin D over-treatment and low PTH, increased dialysis age, diabetes, peritoneal dialysis Treatment, which, diabetes and peritoneal dialysis patients with the highest incidence of non-dynamic bone disease.

In clinical practice, for hypophosphatemia, prone to fractures or pseudo fractures, the application of active vitamin D in the course of increased symptoms, blood iPTH <100 pg / ml CKD5 patients and those with metastatic calcification should be a high degree of Suspected of the presence of non-dynamic bone disease.

Diagnosis and classification of renal bone disease

At present, biopsy under the tetracycline labeling is still the ROD diagnostic gold standard, but due to trauma and the need for special methods, clinical application less. Studies have shown that PTH + osteoprotegerin, PTH + bone specific alkaline phosphatase (bAKP) and different PTH (1-84) / PTH (7-84) fragment ratio combined to help the clinical diagnosis of non-dynamic bone disease, But their specificity and sensitivity can not be compared with bone biopsy, so for high suspicion CKD-MBD and difficult to classify the patients must be early bone biopsy to confirm the diagnosis and guidance of treatment.

KDIGO bone biopsy recommended

KDIGO recommends bone biopsy in the following cases:

• If the serum PTH is 100 ~ 500 pg / ml in CKD patients, there is an increase in unexplained hypercalcemia, bone pain or bone alkaline phosphatase;

• The biochemical indicators are inconsistent and can not explain the disorder of bone metabolism;

• Unexplained fractures or bone pains;

• spontaneous fractures under the cause of fractures without any explanation;

• Unexplained hypercalcemia;

• there is progressive ectopic calcification;

• suspected side effects of aluminum poisoning or other metal poisoning, especially chelation therapy;

• Determine whether there is aluminum poisoning before parathyroid surgery;

• Biopsy using bisphosphonates before treatment.