Chronic Kidney Disease-Mineral and Bone Disorder in Asia

Mineral bone disorder in children with chronic kidney disease: Data from the KNOW-Ped CKD (Korean cohort study for outcome in patients with pediatric chronic kidney disease) study

BACKGROUND

Children with chronic kidney disease (CKD) are at high risk of mineral bone disorder (MBD), which leads to fractures, growth retardation, and cardiovascular disease. We aimed to comprehensively understand the relationship between renal function and factors related to MBD and evaluate the prevalence and distribution characteristics of MBD, specifically among Korean patients from the KNOW-PedCKD cohort.

METHODS

From the baseline data of the KNOW-PedCKD cohort, we examined the prevalence and distribution of MBD in 431 Korean pediatric CKD patients, including the level of corrected total calcium, serum phosphate, serum alkaline phosphatase, serum intact parathyroid hormone (iPTH), fibroblast growth factor 23 (FGF-23), serum vitamin D, fractional excretion of phosphate (FEP), and bone densitometry Z-scores.

RESULTS

The median serum calcium level remained relatively normal regardless of the CKD stage. The levels of 1,25-dihydroxy vitamin D, urine calcium-to-creatinine ratio, and bone densitometry Z-score significantly decreased with advancing CKD stage, while those of serum phosphate, FGF-23, and FEP significantly increased with CKD stage. The prevalence of hyperphosphatemia (17.4%, 23.7%, and 41.2% from CKD stages 3b, 4, and 5, respectively) and hyperparathyroidism (37.3%, 57.4%, 55.3%, and 52.9% from CKD stages 3a, 3b, 4, and 5, respectively) significantly increased with the CKD stage. Prescriptions of medications, such as calcium supplements (39.1%, 42.1%, 82.4%), phosphate binders (39.1%, 43.4%, 82.4%), and active vitamin D (21.7%, 44.7%, and 64.7%) significantly increased with CKD stage 3b, 4, and 5, respectively.

CONCLUSIONS

The results demonstrated the prevalence and relationship of abnormal mineral metabolism and bone growth according to CKD stage in Korean pediatric CKD patients for the first time.

Effect of lanthanum carbonate on the progression of coronary artery calcification in hemodialysis patients: A meta-analysis of randomized controlled trials

INTRODUCTION

Coronary artery calcification and cardiac abnormalities are common in hemodialysis patients. The value of lanthanum carbonate over calcium-based phosphate binders in managing the progression of coronary artery calcification is debated. We reviewed all randomized controlled trials (RCTs) comparing the two strategies in these patients.

METHODS

RCTs comparing lanthanum carbonate with calcium-based phosphate binders used in adult hemodialysis patients were identified in the PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, China Science and Technology Journal, and Wanfang databases.

FINDINGS

Ten RCTs involving 687 patients were suitable for inclusion. Compared with calcium-based phosphate binders, lanthanum carbonate yielded lower coronary artery calcium scores (weighted mean difference, WMD: -74.28, 95% CI: -149.89, 1.33), change in coronary artery calcium scores (WMD: -105.18, 95% CI: -113.83, -96.53), and left ventricular mass index (WMD: -29.95, 95% CI: -54.25, -7.45). Lanthanum carbonate was significantly associated with lower levels of serum phosphate (WMD: -0.18, 95% CI: -0.26, -0.10), calcium (WMD: -0.22, 95% CI: -0.25, -0.20), and fibroblast growth factor 23 (FGF23) (standard mean difference: -3.78, 95% CI: -5.60, -1.96) but not intact parathyroid hormone (WMD: -4.23, 95% CI: -64.12, 55.65). Moreover, a reduced risk of nonfatal cardiovascular events (OR: 0.31, 95% CI: 0.10-0.97) but not all-cause mortality (OR: 1.08, 95% CI: 0.39-3.01) in lanthanum carbonate therapy was observed.

DISCUSSION

In hemodialysis patients, lanthanum carbonate therapy may impede the progression of coronary artery calcification and left ventricular mass index and lead to reduced serum phosphate, calcium, FGF23, and nonfatal cardiovascular events compared with calcium-based phosphate binders. However, more well-designed RCTs are required for confirmation.

Being elderly is not a contraindication of parathyroidectomy for renal hyperparathyroidism and chronic kidney disease-mineral and bone disorder

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) has more influence in the elderly. Parathyroidectomy remains the golden standard for this situation but has tended to be excluded for older patients for many reasons. This study aimed to evaluate the efficacy and safety of the surgery in the elderly population.

METHODS

156 patients were included and arranged into younger (≦65 years of age, n = 139) and elderly (>65 years of age, n = 17) groups. The change of bone mineral density (BMD) data, recovery potential {[(postoperative BMD) - (preoperative BMD)]/(preoperative BMD) ∗ 100%}, surgical successful rate and related complications were collected.

RESULTS

Both groups exhibited significant postoperative improvement on the BMD results. The recovery potential of the elderly was not lower than the younger group. High success rate and none of persistent vocal palsy, hypocalcemia or any sequela were also observed in the elderly.

CONCLUSIONS

Parathyroidectomy is an effective and safe intervention for the CKD-MBD in the elderly.

Associations among Geriatric Nutrition Risk Index, bone mineral density, body composition and handgrip strength in patients receiving hemodialysis

OBJECTIVES

Malnutrition occurs as a complication of hemodialysis (HD) and has been identified as a risk factor for osteoporosis, sarcopenia, and low physical performance. The aim of this study was to assess the associations among nutrition, bone mineral density (BMD), body composition, and handgrip strength (HGS) in patients receiving HD.

METHODS

We enrolled 164 patients receiving HD who have undergone the dual energy x-ray absorptiometry (DXA) examination, categorized according to baseline Geriatric Nutritional Risk Index (GNRI) values calculated by serum albumin levels and body weight index. GNRI was used to evaluate nutritional status, and DXA to investigate BMD and body composition. Additionally, HGS test was performed. Multiple stepwise linear regression analysis was used to identify the factors associated with BMD, T-score, and HGS.

RESULTS

Compared with patients with tertile 1 of GNRI, those with tertile 3 of GNRI tend to have higher lumbar spine BMD and T-score, higher femoral neck BMD, higher total hip BMD, higher left distal mid-third radius BMD and T-score, higher fat mass index, higher android-to-gynoid ratio, higher lean mass index, and higher HGS. An increase in GNRI tertile was associated with an increase of BMD and a decrease of osteoporosis prevalence. The GNRI was positively correlated with BMD and T-score, body composition, and HGS. Low lean mass index and high parathyroid hormone were significantly associated with low BMD and T-score. Additionally, high GNRI and high left distal mid-third radius BMD were significantly associated with high HGS.

CONCLUSIONS

The present study demonstrated that good nutrition, indicated as high GNRI, resulted in higher BMD and T-score, lean mass index, and HGS in patients receiving HD. Using GNRI to evaluate nutritional status and using DXA to investigate BMD and body composition in patients receiving HD is important to bone health and physical performance.

Mineral bone disorders in chronic kidney disease

As the GFR loss aggravates, the disturbed mineral metabolism worsens the bone microstructure and remodelling - scenario, which is known as CKD-mineral bone disease (MBD). CKD-MBD is characterized by : (i) abnormal metabolism of calcium, phosphorus, parathyroid hormone (PTH), or vitamin D; (ii) abnormalities in bone turnover, mineralization, volume linear growth or strength; (iii) soft-tissue calcifications, either vascular or extra-osseous. Uremic vascular calcification and osteoporosis are the most common complications related to CKD-MBD. Disregulated bone turnover by uremic toxin or secondary hyperparathyroidism disturbed bone mineralization and makes it difficult for calcium and inorganic phosphate to enter into bone, resulting in increased serum calcium and inorganic phosphate. Vascular calcification worsens by hyperphosphatemia and systemic inflammation. Since vitamin D deficiency plays an important role in renal osteodystrophy, supplement of nutritional vitamin D is important in treating uremic osteoporosis and vascular calcification at the same time. Its pleotropic effect improves the bone remodeling initiated by osteoblast and alleviates the risk factors for vascular calcification with less hypercalcemia than vitamin D receptor analogs. Therefore, nutritional vitamin D should be considered in managing CKDMBD.