A longitudinal study of the natural history of growth post-transplantation

We have evaluated 587 patients with a functioning renal allograft for at least 54 months in whom baseline and continuous bi-annual height measurements were available. All height data were converted into SD score (SDS) or Z-score using normative tables. The results obtained in these patients were compared to our previous data collected at two years (N = 300) and three years (N = 412) post-transplantation. The demography of the study groups in the three time periods was similar. The height deficit in the first study was -2.41; it was -2.46 at the end of the second study period and was -2.29 at the end of the third study period. Children in the first study period had an improvement in height SDS (delta Z) of +0.18, of +0.16 in the second period, and of +0.11 at the end of the third study period. When improvement in height SD was evaluated by donor source, no differences were noted between living related and cadaver donor transplants. Analysis of height SDS by race revealed that, whereas for Caucasian children a steady improvement of 0.18 was noted during both second and third study periods, there was actual deceleration of growth for the African-American and Hispanic children at the end of the third study period (P < 0.02). Multivariate analysis showed that only initial height deficit and recipient age were independent predictors of improved height post-transplantation. Catch up growth, defined as an improvement of 1 SDS, was seen only in those with the greatest deficit or in children 0 to 1 year of age. Overall, catch up growth was seen in only 47% of 2 to 5 year olds. For children over the age of six years who form 72% of the total study cohort, little catch up growth was noted. Our long-term studies reveal that in the first years post-transplantation, when renal function is still stable, height acceleration does not occur in most of the children over the age of six years, and alternative strategies are necessary to improve the quality of life of these children.