Estimation of calcium, phosphorus, alkaline phosphatase and intact parathyroid hormone in various stages of chronic kidney disease

BACKGROUND: CKD is an international public health problem affecting 5–10% of the total population. As kidney function declines, there is a progressive deterioration in mineral homeostasis with alteration in serum concentrations of phosphorus, calcium and hormones like parathyroid hormone and alkaline phosphatase. Derangements of mineral metabolism occur during early stages of CKD. If not diagnosed, these disturbances will lead to progressive decline in renal functions & cause cardiovascular, soft tissue calcification, renal osteodystrophy etc., Very few studies have been done on Indian population, thus this study has been undertaken to know the levels of PTH, calcium and phosphorus in patients with CKD. AIM 1. To correlate serum intact parathyroid hormone, urea, creatinine, calcium, phosphorus and alkaline phosphatase in various stages of CKD and to compare the same with the control group. 2. To find the role of intact parathyroid hormone in the early diagnosis of mineral disturbances in CKD patients. METHODS A case-control study conducted at CMCH & RC, Trichy. It included 50 cases in various stages of CKD and 50 controls. Blood urea, creatinine, intact parathyroid hormone, serum calcium, phosphorus and alkaline phosphatase levels where measured in both cases and controls. RESULTS: The values of PTH in cases was 136.80±92.70, and controls was 52.47±16.34 (p<0.001). The levels of calcium in cases was 8.35±1.07 and controls was 8.98±1.07 (p<0.001), phosphorus values in cases was 4.40±1.70 and controls was 3.47±0.62 (p<0.001). Thus statistically significant increase in PTH levels and significant alteration in calcium and phosphorus levels were seen in patients. CONCLUSION: The levels of PTH increased as the kidney disease progresses. This is associated with increase in levels of phosphorus and fall in calcium. The PTH levels starts increasing with stage III CKD, while calcium and phosphorus are still within range. Thus PTH levels can be used as marker for diagnosis of mineral disturbances in early stages of CKD.