Introduction: Leptin, is an anorexigenic hormone that's secreted by fat tissue, & affect appetite. Aim of the study: The present study evaluated serum leptin level, & its relation to growth parameters in pediatric patients with different stages of CKD. Methods: a cross-sectional study that was conducted on 87 subjects, who were divided into 3 groups equally; CKD stage 5 on regular hemodialysis (CKD5d), & CKD stage 2-4, & age & gender matched controls. Patient with diabetes, infected with hepatitis C virus, & on growth hormone therapy were excluded. Full history taking, assessment of growth parameters using gender & age specific Z-scores of heights, weight & body mass index were done. Fasting serum leptin, calcium, phosphorus, PTH, albumin, total proteins, iron & hemoglobin were measured.Results: Our patients had significantly lower growth parameters compared to controls. Hypocalcemia, high PTH, iron deficiency anemia & hypoalbuminemia were significant in CKD2-4 groups compared to other groups. Serum leptin was abnormally high in 12.6% of CKD patients. The median leptin level was comparable between the groups (p=0.20). Serum leptin hadn't changed significantly as regards gender, BMI Z-scores, diagnoses, or CKD stage (p= 1.00, 0.379, 0.542, 0.171 respectively). A negative correlation was found between leptin level & CKD duration (r = -0.276, P = 0.036), otherwise, no correlations were found with clinical & laboratory variables. Conclusion & recommendations:Leptin level was not affected by CKD stage & not a useful marker for growth in pediatric CKD patients. Large studies on relationship between leptin & growth are needed.

Objective Vitamin D has many immune benefits and because its deficiency impacts most age groups, it became a nutrient of interest in the coronavirus disease 2019 (COVID-19) era. The objective of this study was to highlight the contribution of vitamin D status to the disease severity of hospitalized pediatric patients suffering from COVID-19 infection. Methods This was a cross-sectional study that was conducted on 42 children with documented positive polymerase chain reaction for COVID-19 infection. Detailed history taking and thorough clinical examination were done for each recruited patient. Besides the laboratory and radiological assessment done for COVID-19 patients, 25 hydroxy vitamin D levels [25(OH) D] in the serum were estimated using enzyme linked immunosorbent assay. Results Using the cutoff level of 10 ng/mL, only 40% of the patients were below this level and 60% had their vitamin D level more than or equal to 10 ng/mL. Significantly more patients of the first group needed oxygen support (denoting more severe COVID-19 infection and lung involvement). The older the patients, the more evident was vitamin D deficiency among them, and 25(OH) D values were not correlated to weight for length nor weight categories in the studied series of patients suffering from COVID-19. Conclusion Vitamin D deficiency affects the severity of pediatric COVID-19 infection in hospitalized patients. It is prudent to advise vitamin D level assessment in such cases and promptly manage the patients accordingly. We recommend further studies to assess the effect of vitamin D supplementation on the clinical outcome of COVID-19 in the pediatric population and other vulnerable groups.