title: Bone mineral disorders in pediatric and adolescent renal transplant recipients.
abstract: Incomplete resolution of abnormalities of mineral metabolism associated with CRF results in the relatively high prevalence of ROD in pediatric kidney recipients. This non-randomized, cross-sectional, and analytic-descriptive study on bone density, vitamin D, and mineral metabolism was performed in 57 children and adolescents who had received a total of 60 renal allografts in Shiraz, Iran. The height and weight of the patients were measured; their serum calcium (Ca), phosphorus (P), Alk-P, PTH, 25(OH)-vitamin D(3), BUN, creatinine, and electrolyte levels were analyzed, and a complete blood count was performed. In addition, standard radiologic bone assessments, which included conventional left hand-wrist radiography and bone mineral densitometry by the DXA technique, were carried out. Special pediatric software was used for age-related interpretation of the Z-scores of BMD. SPSS(®) software (version 15) was used for statistical analyses. We studied 57 patients (27 males [47.4%]) with a mean age of 18.7 ± 4.25 (9-27) yr and a mean age at transplantation of 13.1 ± 3.46 (4.5-20) yr. They had a post-transplantation follow-up of 67.1 ± 33.8 (6-132) months, and all had well-functioning allografts at enrollment. The mean height age of the patients was 11.9 ± 1.8 (6-15.5), and the mean bone age was 15.6 ± 3.3 (7-19) yr, which corresponded to mean height-age and bone-age retardations of 5.7 ± 2.3 (0.5-10.5) and 1.22 ± 1.47 (0-7) yr, respectively. Hyperphosphatemia and hypercalcemia were each found in nine patients (15.8%), hypophosphatemia in five (8.8%), and hypocalcemia in none of the patients. Seven out of 57 patients (12.3%) had a (Ca×P) product of more than 55 mg(2)/dL(2). Hyperparathyroidism was found in 27 (47.3%) and vitamin D(3) deficiency in four (7%) of the cases. The serum level of Alk-P was higher than the age-related normal range in 20 patients (35%). Left hand-wrist radiography showed no radiologic sign of ROD in any patient. The mean BMD Z-score was -1.77 ± 1.13 (-4.2-1.1) for the lumbar spine and -1.64 ± 0.89 (-3.9 to 1.9) for the femoral neck. "Stepwise backward regression" revealed a significant inverse correlation between the serum level of PTH and the GFR of the transplanted kidney; this correlation was independent from the influence of other variables such as Ca, P, and Alk-P (p = 0.011, β = -1.556). Bone age and height age both showed significant correlations with age at transplantation and serum levels of P (p < 0.001), but only bone age had a meaningful correlation with Alk-P (p = 0.036). The BMD Z-scores showed statistically meaningful correlations with the serum level of Alk-P, which were independent from the influence of other variables such as Ca, P, and PTH (p ≤ 0.002). Our study revealed a relatively high prevalence of bone mineral disorder in pediatric kidney recipients, which suggests the need for a routine program for periodic screening of these patients to facilitate early diagnosis of either persistent or evolving manifestations of disturbed mineral metabolism, especially ROD.
authors.affiliation: Department of Pediatric Nephrology, Nephro-Urology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Derakhshan
authors.forename: Afshin G
authors.initials: AG
authors.lastname: Behbahan
authors.forename: Mehrzad
authors.initials: M
authors.lastname: Lotfi
authors.forename: Gholam-Hossein
authors.initials: GH
authors.lastname: Omrani
authors.forename: Mohammad-Hossein
authors.initials: MH
authors.lastname: Fallahzadeh
authors.forename: Mitra
authors.initials: M
authors.lastname: Basiratnia
authors.forename: Ghamar H
authors.initials: GH
authors.lastname: Al-Hashemi
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D017677:Age Distribution; D001774:Blood Chemical Analysis; D018488:Bone Demineralization, Pathologic / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016001:Confidence Intervals; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000601:surgery; D007677:Kidney Function Tests; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000379:methods; D008297:Male; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology; D015995:Prevalence; D012044:Regression Analysis; D018570:Risk Assessment; D017678:Sex Distribution; D014184:Transplantation, Homologous
chemical_list: D003404:Creatinine