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.

Growth impairment shows an age-dependent pattern in boys with chronic kidney disease.

The impact of chronological age on longitudinal body growth from early childhood through adolescence using detailed anthropometric methods has not yet been studied in children with chronic kidney disease (CKD). We have evaluated growth failure by measuring four components of linear growth: body height (HT), sitting height (SHT), arm length (AL) and leg length (LL). Data were prospectively collected for up to 7 years on 190 boys (3-21 years old) with congenital or hereditary CKD (all had developed at least stage 2 CKD by the age of 10 years). Patients showed the most severe growth failure in early childhood, followed by an acceleration in growth in pre-puberty, a slowing-down of growth at puberty, as expected, and thereafter a late speeding-up of growth until early adulthood. This pattern was observed irrespective of the degree of CKD and different treatment modalities, such as conservative treatment, recombinant human growth hormone (rhGH) therapy or transplantation. LL showed the most dynamic growth changes of all the parameters evaluated and emerged as the best indicator of statural growth in children with CKD. A specific age-dependent pattern of physical growth was identified in pediatric male CKD patients. This growth pattern should be considered in the evaluation of individual growth and the assessment of treatment efficacy such as rhGH therapy.