AUTHOR=Karava Vasiliki , Kondou Antonia , Dotis John , Christoforidis Athanasios , Taparkou Anna , Tsioni Konstantina , Farmaki Evangelia , Kollios Konstantinos , Siomou Ekaterini , Liakopoulos Vassilios , Printza Nikoleta 

TITLE=Association Between Secondary Hyperparathyroidism and Body Composition in Pediatric Patients With Moderate and Advanced Chronic Kidney Disease

JOURNAL=Frontiers in Pediatrics

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2021.702778

DOI=10.3389/fped.2021.702778

ISSN=2296-2360

ABSTRACT=<p><bold>Objective:</bold> This single center cross-sectional study aims to investigate the association between secondary hyperparathyroidism and body composition in pediatric patients with moderate (stage 3) and advanced (stage 4–5) chronic kidney disease (CKD).</p><p><bold>Methods:</bold> 61 patients (median age: 13.4 years) were included. Body composition indices, including lean tissue index (LTI) and fat tissue index (FTI), were measured using multi-frequency bio-impedance spectroscopy. Muscle wasting was defined as LTI adjusted to height-age (HA) z-score &lt; −1.65 SD and high adiposity as FTI z-score &gt; 1.65 SD. Serum mineral metabolism parameters, including serum intact parathormone (iPTH), calcium, phosphorus and 25-hydroxyvitamin D, as well as serum leptin were measured in each patient. In advanced CKD patients, the mean values of serum mineral laboratory parameters of the 6 months prior to body composition assessment were recorded, and alfacalcidol index, defined as weekly alfacalcidol dose (mcg/week) per pg/ml of iPTH × 1,000, was calculated.</p><p><bold>Results:</bold> In moderate CKD (31 patients), high iPTH (&gt;90 ng/ml) was observed in 10 (32.3%) patients and was associated with higher FTI z-score (<italic>p</italic> = 0.022). Moreover, serum iPTH was negatively correlated to LTI HA z-score (rs = −0.486, <italic>p</italic> = 0.006), and positively correlated to serum leptin levels (rs = 0.369, <italic>p</italic> = 0.041). The positive correlation between FTI z-score and iPTH (rs = 0.393, <italic>p</italic> = 0.039) lost significance after adjustment for serum leptin. iPTH was positively associated with high adiposity (12 patients, 38.7%) after adjustment for the other mineral metabolism parameters (OR 1.023, 95% CI 1.002–1.045, <italic>p</italic> = 0.028). In advanced CKD (30 patients), no significant correlation was observed between iPTH and body composition indices and serum leptin levels. Eleven (36.7%) patients with muscle wasting presented lower alfacalcidol index (<italic>p</italic> = 0.017). Alfacalcidol index ≤ 24 was strongly associated with muscle wasting after adjustment for CKD stage and other mineral metabolism parameters (OR 7.226, 95% CI 1.150–45.384, <italic>p</italic> = 0.035).</p><p><bold>Conclusion:</bold> Secondary hyperparathyroidism is associated with high adiposity in moderate but not in advanced CKD, with leptin acting as a potential contributive factor. In advanced CKD, targeting higher alfacalcidol weekly dose per each unit of serum PTH seems beneficial for preventing muscle wasting.</p>