Miroslav Živičnjak

Patterns of Growth after Kidney Transplantation among Children with ESRD

BACKGROUND AND OBJECTIVES Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2-18 years with a median follow-up of 3.4 years (interquartile range, 1.9-5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments. RESULTS During early childhood, patients showed lower mean SD scores (SDS) for height (-1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2-4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05). CONCLUSIONS Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome.

Three-Year Growth Hormone Treatment in Short Children with X-Linked Hypophosphatemic Rickets: Effects on Linear Growth and Body Disproportion

CONTEXT Children with X-linked hypophosphatemic rickets (XLH) are prone to progressive disproportionate stunting despite oral phosphate and vitamin D treatment. OBJECTIVE Our objective was to analyze the effects of GH treatment on stature and lengths of linear body segments in short children with XLH. DESIGN, SETTINGS, AND PATIENTS A 3-yr randomized controlled open-label GH study in short prepubertal children with XLH (n = 16) on phosphate and calcitriol treatment was conducted. A cohort of XLH patients (n = 76) on conservative treatment served as an XLH reference population. MAIN OUTCOME MEASURES Changes in SD scores (SDS) of stature and linear body segments, i.e. sitting height, leg and arm length, and sitting height index (i.e. ratio between sitting height and stature) were the main outcome measures. RESULTS XLH patients presented at time of enrollment with significant impairments of stature (-3.3 SDS) and linear body segments compared with healthy children. Leg length (-3.8 SDS) was most impaired, whereas sitting height (-1.7 SDS) was best preserved. The markedly elevated mean sitting height index (+3.3 SDS) reflected severe body disproportion. GH resulted in a sustained increase in linear growth (stature, +1.1 SDS; sitting height, +1.3 SDS; leg length, +0.8 SDS; arm length, +1.1 SDS; each P < 0.05 vs. baseline), whereas no significant changes were observed in controls. Mean height SDS at 3 yr did not significantly differ between groups. Sitting height index remained stable in both the GH-treated patients and in study controls but increased further in the XLH-reference population. CONCLUSIONS The 3-yr GH treatment improved linear growth without progression of body disproportion in short children with XLH.

Prematurity, small for gestational age and perinatal parameters in children with congenital, hereditary and acquired chronic kidney disease

BACKGROUND Low birth weight has been identified as a risk factor for chronic kidney disease (CKD). METHODS We analysed perinatal parameters taken from the National Birth Certificates of 435 children with CKD stages 3-5 of different aetiology and time of onset of CKD. Diseases were classified as congenital with onset of renal disease during fetal life (n = 260; 60%), hereditary as genetically determined with onset after 3 months of life (n = 93; 21%) and acquired CKD (n = 82; 19%). RESULTS The rates of prematurity and small for gestational age (SGA) were elevated in children with congenital (39.3% and 29.2%), hereditary (24.7% and 22.6%) and acquired CKD (15.5% and 29.3%); these compared to 8% (for both) in the normal population. Newborns with congenital CKD had a significantly lower gestational age [median 38 weeks, interquartile range (IQR) 36-40 weeks] than those with hereditary (39.9 weeks, IQR 37.5-40 weeks) or acquired CKD (40 weeks, IQR 38-40 weeks; P < 0.001). Median birth weight and length were lower in newborns with congenital than in hereditary and acquired diseases [2975 g (IQR 2460-3420 g) versus 3250 g (IQR 2740-3580 g) and 3260 g (IQR 2858-3685 g) (P < 0.01); 49 cm (IQR 47-52) versus 50 cm (IQR 48-52.8) and 51 cm (IQR 49-53) (P < 0.01)]. Head circumference was smaller (P < 0.05), and Apgar scores were lower (P < 0.005) in newborns with congenital diseases than in hereditary and acquired diseases. CONCLUSIONS Children with congenital CKD had the highest rate of prematurity, a significantly lower birth weight, length, head circumference and Apgar score than newborns with hereditary or acquired CKD. Irrespective of the aetiology of CKD, all of the children had a significantly higher rate of SGA and prematurity than the reference population. We conclude that both SGA and prematurity predispose for advanced renal disease in childhood and that fetal kidney disease impairs fetal growth.