Bone mineral density in pediatric and adolescent renal transplant patients: How to evaluate

Abstract

Reduced bone mass is a common complication of renal transplantation in adults but only few data are present for pediatric transplant patients. Bone mineral status of pediatric renal transplant patients ages ranging from 7.5 to 17.6 years (mean age 14.9 +/- 2.3) who were at least 6 months postrenal transplantation was examined. Bone mineral density (BMD) of lumbar vertebrea and femoral neck was determined by dual energy X-ray absorptiometry (DEXA) and z-scores according to age, puberty, height and bone age were compared to sex and ethnic specific reference data. z-scores were calculated for both areal and volumetric bone density. BMD L1-4 z-scores were more than 2 SD below the mean according to chronological age in 12 patients (63%), pubertal status in six patients (31.5%), bone age in five patients (26.3%) and height in five patients (26.3%). The BMD femoral neck z-scores were more than 2 SD below the mean according to age in 10 patients (55.5%), puberty in five patients (27.7%), bone age in three (16.6%) patients and height in five (26.3%) patients. Correction of the vertebrae and femoral neck for bone size yielded osteoporotic values for seven patients (36.8%) for lumbar BMD and for four patients (22%) for femoral neck BMD. The use of aBMD in growth-retarded children has some restrictions in determining z-scores. Deficits in spinal bone density still persisted after correcting for height, puberty, bone age and volume. In renal transplant patients who have short stature it is reasonable to give values corrected for height, puberty, bone age and bone size and interpret each of these values for each patient.

Bone mineral disorders in pediatric and adolescent renal transplant recipients

“…Gökşen et al. (7) declared that both the height and bone ages of five out of 19 (26.3%) pediatric kidney recipients in Turkey were more than two s.d. below the mean according to their chronological age.…”

“…below the mean according to their chronological age. They were examined at least six months post‐renal transplantation (7). Many studies on pediatric kidney recipients have yielded the same results (13, 19, 24, 27, 28).…”

“…The wide spectrum of factors that are implicated in bone demineralization and their long‐term influences on BMD in children during the course of CKD and after renal transplantation is still not well understood. Many researchers have emphasized that there is currently little data available for pediatric transplant patients, and in many cases these data are not only insufficient but also conflicting (1, 4–14).…”

Reference-Class Problems Are Real: Health-Adjusted Reference Classes and Low Bone Mineral Density

“…Others make similar comments, arguing that “The human body tries to adapt bone mass and bone geometry to body height and weight and not to age” ( Gökşen et al, 2005 , 466). Physicians also point out that muscle mass and bone mass are tightly correlated, supporting the view that bone and muscle act as a functional unit.…”

Ο Ρόλος Της Ποσοτικής Υπερηχοτομογραφίας Στον Οστικό Έλεγχο Παιδιών Με Χρόνια Νεφρική Νόσο Και Μεταμόσχευση Νεφρού

“…που με 18 μήνες και στη συνέχεια, ανάλογα με τη μελέτη, παρουσιάζεται κάποια βελτίωση. Το ίδιο φαίνεται και από μετρήσεις της οστικής πυκνότητας, που είναι παθολογικές σε σχέση με υγιείς πληθυσμούς, ακόμη και 2 χρόνια μετά τη νεφρική μεταμόσχευση, σε ποσοστό που ξεπερνάει το 50% των ασθενών64 .Η εφαρμογή θεραπείας με ασβέστιο και καλσιτριόλη φαίνεται να βελτιώνει την οστική πυκνότητα σε μεταμοσχευμένους ασθενείς. Αντίθετα η χρήση διφωσφονικών έχει αντικρουόμενα αποτελέσματα και σχετίζεται με την εμφάνιση αδυναμικής νόσου80 .3.…”