| BackgroundDisturbances in calcium and phosphorus metabolism are almost invariable consequences of chronic kidney disease. Long-term calcium and phosphorus metabolism disorders in chronic kidney disease can lead to hyperparathyroidism, mineral and bone disease, immune dysfunction, metastatic calcification, including lung, heart, heart valves and blood vessels. These pathophysiological changes cause many clinical manifestations of CKD and associated with increased mortality of chronic renal failure.The kidney plays a pivotal role in maintaining calcium and phosphorus balance by modulating the amounts of each mineral that are excreted daily in the urine.1,25-dihydroxyvitamin D and parathyroid hormone are the important factors in the process. The capacity to regulate calcium and phosphorus metabolism homeostasis becomes compromised progressively as renal function declines, so mineral metabolism homeostasis is disturbed, which is hyperphosphatemia and hypocalcemia. High phosphorus can increase the levels of PTH by the way of stimulating the PTH secretion in parathyroid glands directly, and reducing the calcium concentration and reduce the synthesis of active vitamin D indirectly. PTH is synthesized in parathyroid tissue and stored in secretory granules with parathyroid cells, from which it is secreted.Recently, in more literature, hyperphosphatemia was associated with cardiovascular events and mortality in CKD patients. What is the relationship between high phosphorus levels with renal function and renal pathological damage relationship in the end? So far, the relationship is unclear.In this study, we collected683cases of clinical data and597cases of renal pathological report in patients with chronic kidney disease from renal biopsy-proven nephrology. Our aim is to investigate the relationship between the levels of serum calcium, phosphorus, PTH and renal function; to approach the association of serum calcium, phosphorus, PTH values with renal pathological injury. Part I:The relationship between serum calcium, phosphorus, PTH and clinical parameters in patients with CKD from renal biopsy-proven nephrologyAimTo investigate the clinical features according the stages of CKD and the relationship between serum calcium, phosphorus, PTH and clinical parameters in patients with CKD from renal biopsy-proven nephrology, in providing evidence of clinical care in CKD patients.MethodsCollect clinical and laboratory data from693biopsy-proven nephrology cases between January2010and December2011. All data include age, sex, height, weight, albumin, serum creatinine, blood urea nitrogen, serum uric acid, MDRD-GFR, hemoglobin and serum calcium, phosphorus, PTH. All renal-biopsy samples were obtained by percutaneous method using a tricot needle under ultrasound guidance and stained by IgG、IgA、IgM、C3、C4and C1q for immunofluorescence microscopy and by hematocylin-eosin, periodic acid Schiff and Masson’s trichrome stain for light microscopy.Results1. Male to female ratio was1.03:1in683patients with CKD, average age in renal biopsy was44.42±15.35(12-83) years.311patients (45.53%) have hypertension,63cases (9.22%) have diabetes mellitus.2. The percentages of CKD1-5stages were221cases (32.26%),160cases (23.43%)172cases (25.18%),68cases (9.96%),62cases (9.08%).3. The mean value of serum calcium is2.1±0.18mmol/L. The minimum and maximum levels serum calcium are0.92mmol/L,2.75mmol/L.361patients (52.9%) have hypocalcemia (<2.15mmol/L). In the group of older age (>50years), the rate of hypocalcemia increased,61.6%patients in older age have hypocalcemia. With the descending of serum albumin levels, the rate of hypocalcemia in the group step-up. When serum album levels<30g/L, above90%patients have hypocalcaemia.4. The mean value of serum phosphorus is1.34±0.32mmol/L. The minimum and maximum levels of serum phosphorus are0.52mmol/L,3.55mmol/L.287cases (42%) have hyperphosphatemia (>1.34mmol/L). There is no significant in the distribution of hyperphosphatemia among the groups of serum albumin and in the sex group. But the rate of hyperphosphatemia in older age group becomes lower. When patients age<30years,68.8%have hyperphosphatemia.5. There is169cases (24.7%) with elevated PTH levels (65pg/ml), of which57.4%patients were in CKD4-5stages,29%in CKD3stage,13.6%in CKD1-2stages. Overall, when serum PTH values is>100pg/ml, renal function have dropped to low levels, serum calcium levels have decreased apparently, and serum phosphorus levels have descended significantly. There is no significant difference in the groups of age, sex, hypertension, diabetes mellitus, and serum albumin.6. When MDRD-GFR<30ml/min/1.73m2,69.2%patients have hypocalcemia,77.8%hyperphosphatemia,74.6%serum elevated PTH levels. In CKD3stage,53.5%patients were hypocalcemia, with serum calcium levels<0.95mmol/L in20.9%. In CKD5stages,82.9patients performed hypocalcemia, with serum calcium levels<0.95mmol/L in30.6%. In CKD1-3stages, the phenomenon about serum elevated phosphorus levels in patients are common, almost with the levels from1.34mmol/L to1.53mmol/L; in CKD4stage,67.7%patients have hyperphosphatemia; however, in CKD5stage,67.7%patients performed elevated serum phosphorus levels (>1.64mmol/L) and90.4%patients were hyperphosphatemia (>1.34mmol/L). In patients with CKD3stages,49cases (28.5%) were serum increased PTH levels, with the levels are from65pg/ml to100pg/ml in32cases (18.6%) and above100pg/ml in17cases (9.9%).7. With the deterioration of renal function, serum PTH level increased serum phosphorus level elevated and serum calcium value decreased. When serum creatinine level was in90-115μmol/L, only serum PTH value increased significantly than the level in≤90μmol/L and the rate of serum PTH level in50-65pg/ml is elevated in the group of creatinine level in90-115μmol/L.ConclusionsThis study demonstrates the high prevalence of hypocalcemia, hyperphosphatemia and elevated PTH levels in patients with chronic kidney disease. Serum elevated PTH levels are more sensitivity than serum calcium and phosphorus in assessing the aggravation of renal function. When the level of serum PTH was in50-100pg/ml, eGFR values may be below60ml/min/1.73m2. PART Ⅱ: Association of serum calcium, phosphorus and PTH levels with kidney pathological lesion in chronic kidney diseaseAimTo investigate association of serum calcium, phosphorus, PTH and renal pathological injury in patients with CKD from renal biopsy-proven nephrology, for the purpose of providing evidence of clinical care in CKD patients.MethodsCollect clinical and laboratory data from597biopsy-proven nephrology cases between January2010and December2011. All data include age, sex, height, weight, albumin, serum creatinine, blood urea nitrogen, serum uric acid, MDRD-GFR, hemoglobin and serum calcium, phosphorus, PTH. Renal pathological lesions were evaluated according to Katafuchi semi-quantative standards, including glomerular, tubulointerstitial damage.Result1. Male to female ratio was1:1in597patients with CKD, average age in renal biopsy was43.75±15.33(13-83) years.270patients have hypertension,59cases (9.22%) have diabetes mellitus. IgAN is the most frequent type, accouting for39.87%.16.75%patients have MN, and6.87%patients have minimal change disease.2. With the aggravation of glomerulosclerosis, serum PTH value and the rate of patients with serum elevated PTH value increased significantly than that of serum calcium and phosphorus value. However, serum phosphorus value did not step up until glomerulosclerosis in patents increased seriously. Increases in serum PTH began to occur at moderate glomerular sclerosis, and appear earlier than elevated serum phosphorus and decline in serum corrected calcium.3. When patients happened to severe renal tubulointerstitial lesion, the level of serum phosphorus increased more significantly than that of the other groups and the value of serum calcium decreased, compared to that in patients with mild tubulointerstitial lesion. Serum PTH values began to increase in patents with moderate renal tubulointerstitial injury, and occur earlier than elevated serum phosphorus and decline in serum corrected calcium.ConclusionWhen the patients represented moderate glomerulosclerosis and tubulointerstitial damage, serum PTH values elevated apparently and gradually. However, serum phosphorus values did not increased until patients have severe glomerulosclerosis and tubulointerstitial lesions. Serum corrected calcium levels did not decline apparently. |
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