The Prevalence of Osteopenia in Pediatric Renal Allograft Recipients Varies with the Method of Analysis

Background: Pediatric renal allograft recipients often suffer from osteopenia and the potential for increased fractures. Although modern densitometers are widely available, their use in children is complicated by lack of optimal interpretive criteria. Methods: We reviewed dual energy X-ray absorptiometry (DEXA) studies in 33 patients with functional renal allografts 4.4±3.6 years after transplantation. We interpreted our data using three previously described methods of assigning bone mineral density (BMD) Z scores. Results: BMD was directly related to age, height, weight, body surface area, and pubertal status (p <0.001). Using gender-mixed reference data matched by chronological age, the mean BMD Z score was -0.9±1.3 vs. 0.4±1.4 when matched by height-age (p <0.001). Height-age adjustment particularly increased the BMD Z score of pubertal adolescents. In a subset of 22 patients, gender-matched reference data led to different results from the gender-mixed reference population (mean BMD Z score 0.0±1.7 vs. -0.8±1.4, p <0.001). Conclusions: The perceived prevalence of osteopenia among pediatric kidney transplant recipients differs using analysis based on chronological age, height-age, or gender-matched reference data. Further studies are necessary to determine the clinical significance of measured bone density in this population.