Vitamin D Status in Children with Chronic Kidney Disease

BACKGROUND: Vitamin D deficiency is a major contributor to secondary hyperparathyroidism in patients with chronic kidney disease (CKD). The objective of this study was to determine the vitamin D status in children with CKD. METHODS: This cross-sectional study was conducted in the Department of Pediatric Nephrology, National Institute of Child Health (NICH), Karachi from January 2013 to December 2013. Ninety patients aged 3 months to 17 years with CKD were included. CKD was categorized into 5 stages based on glomerular filtration rate (GFR) and stage 4 and 5 were labeled as advanced CKD. Patients on 25-hyroxy vitamin D (25OHD) therapy were excluded. Radioimmunoassay was used to measure 25OHD level and it was defined as sufficient (>30-80 ng/ml), insufficient (16-30), mild to moderate deficiency (5-15 ng/ml) and severe deficiency (<5ng/ml). Data including age, gender, blood urea (U), serum creatinine (Cr), GFR, CKD-stage, etiology, serum calcium (Ca), serum phosphorus (P) , serum alkaline phosphatase (ALP), serum parathyroid hormone (PTH) and serum 25OHD level were collected and analyzed by SPSS using descriptive statistics. RESULTS: Of the 90 patients, 55 (61.1%) were males. Mean age was 7.4+ 4.6 years. Mean U, Cr and GFR were 113.5+ 82.0 mg/dL, 3.9+3.4 mg/dL and 28.8+28.3 mL/min/1.73 m 2 respectively. Majority (66.7%) had advanced CKD and 44.4 % were undergoing dialysis. Etiologies of CKD were renal hypoplasia–dysplasia (36.6%), stone-disease (18.9%), posterior-urethral valves (16.7%) and juvenilenephronophthisis (12. 2%). Mean ± standard deviation of serum Ca was 8.3 + 1.6 mg/dL, P 5.2+1.7 mg/dL, ALP 418.3+298 U/L and PTH 370.6+320.7 pg/ml. Mean 25OHD level was 18.9+16.8 ng/ml and its levels in males (17.73+10.63) and females (16.91 + 9.74) were similar (p=0.79). Mean 25OHD level was suboptimal in 79 patients (87.8%); 37 (41.1%) had insufficiency, 33 (36.7%) had mild to moderate deficiency whereas 9 (10%) had severe 25OHD deficiency. CONCLUSION: Vitamin D status was suboptimal in 87.8% of cases and 25OHD deficiency was severe in advanced CKD. Conflict of Interest: None declared This article has been peer reviewed. Article Submitted on: 3 February 2015 Article Accepted on: 20 May 2015 Funding Sources: None declared Correspondence to: Dr Khemchand N. Moorani Address: National Institute of Child Health, Karachi, Pakistan Email:khemchandn@hot mail.com Cite this article: Moorani KN, Asim S, Iqbal S. Vitamin D Status in Children with Chronic Kidney Disease. J Pioneer Med Sci 2015; 5(3):94-98 attributed to deficiency of 1,25 dihydroxycholecalciferol {1, 25(OH) 2 D}, and combined with hyperphosphatemia, leads to disordered bone turnover and mineralization, known as mineral bone disorder (MBD). The dysregulated calcium (Ca), phosphorus (P), parathyroid hormone (PTH), and 25hydroxyvitamin D (25OHD) along with increased fibroblast growth factor – 23 (FGF-23) result in vascular calcification which may contribute to high cardiovascular diseases and mortality both in children and adults[1,6-8]. INTRODUCTION Chronic kidney disease (CKD) is defined as an irreversible progressive renal damage lasting for three or more months [1, 2]. Reported prevalence of CKD in Pakistan varies from 1229% of renal diseases in pediatric tertiary care centers [3, 4]. Patients with long standing CKD are at high risk of vitamin D deficiency (VDD) and it is a major contributor in the pathogenesis of secondary hyperparathyroidism (SHPT). SHPT in advanced stages of CKD is chiefly