The high prevalence of chronic kidney disease-mineral bone disorders: A hospital-based cross-sectional study

Abstract

Mineral bone disorder (MBD) is an important complication of chronic kidney disease (CKD). However, there are limited data on the pattern of MBD in Indian CKD population. The aim of this study was to describe spectrum of MBD in patients with CKD in our center. This was a hospital-based cross-sectional observational study. Patients with stage 4 and 5 CKD were included in this study. Those receiving calcium supplement, vitamin D or its analogues, and calcimimetic were excluded. Serum/plasma levels of creatinine, albumin, calcium, phosphate, total alkaline phosphatase (TAP), intact parathormone (iPTH), and 25-OH vitaminD (25-vitD) were measured. Radiological survey of bones was carried out in all cases, and echocardiography done in selected patients. Statistical analysis was done using Sigmaplot 10.0 software. A total of 150 patients (114 males, 36 females) were included in this study. Mean age was 45.67±16.96 years. CKD stage 4 and 5D were found in 26% (n=39) and 74% (n=111) of study population, respectively. The most common underlying native kidney diseases in patients of CKD 4 and 5D were diabetic nephropathy (41.03%) and CGN (41.44%), respectively. Median (first quartile, third quartile) values for serum levels of corrected calcium (cCa), phosphate, cCaXPO4 product, TAP, plasma iPTH, and 25-vitD in stage 4 CKD were 8.36 (7.79, 8.91) mg/dL, 4.9 (3.92, 6.4) mg/dL, 41.11 (34.01, 53.81) mg(2)/dL(2), 97 (76.5, 184.25) IU/L, 231 (124.5, 430.75) pg/mL, and 12 (6.98, 23.55) ng/mL, respectively; and in stage 5D CKD were 8.36 (7.66, 8.95) mg/dL, 5.7 (4.23, 6.95) mg/dL, 46.5 (37.16, 54.47) mg(2)/dL(2), 180 (114.5, 276.25) IU/L, 288 (169.75, 625.0) pg/mL, and 18.4 (10.0, 26.4) ng/mL, respectively. Prevalence of hypocalcemia (56.41% vs. 54.95%), hyperphosphatemia (64.10% vs. 70.27%), and hyperparathyroidism (84.62% vs. 88.29%) was not different between patients with CKD 4 and 5D. However, iPTH level outside the target range and increased TAP level were significantly (P<0.001) more common in CKD stage 5D. Multiple logistic regression analysis for hyperparathyroidism revealed significant inverse correlation with cCa in CKD 5D. There were no significant differences in vitamin D status and prevalence of valvular calcification between CKD stage 4 and 5D. X-ray revealed renal osteodystrophy in 8 (5.33%) patients, while it was normal in 118 (78.67%) patients. Secondary hyperparathyroidism, hyperphosphatemia, hypocalcemia, increased TAP, and 25-OH vitamin D deficiency and insufficiency were quite common in CKD 4 and 5 patients. The commonest type of MBD in CKD 4 and 5D was secondary hyperparathyroidism.

Keywords: Chronic kidney disease; hyperparathyroidism; hyperphosphatemia; hypocalcemia; mineral bone disorder.