Correlation between criteria of diagnosis of low bone mineral density in adult and pediatric thalassemic patients: a prospective study.

Abstract

Finding the correlation between criteria for low bone mineral density (BMD) in adulthood and childhood is a matter of interest. This study aimed to find how many of thalassemic patients with Z-Score ≤-2 during childhood, will be found with T-Score ≤-2.5 or Z-Score ≤-2.0 in adulthood. The results of BMDs (one in childhood and one in adulthood) of 30 patients with beta thalassemia major (12 males and 18 females) with mean age of 17.63 y/o in childhood and 20.67 y/o in adulthood were studied, retrospectively. A Norland XR-46 device was used for measuring BMD. Z-Score ≤-2 was found in 33% of children and T-Score ≤-2.5 and Z-Score ≤-2.0 was found in 43 and 66% of adults, respectively. Correlation of pediatric Z-scores was good with adult T-scores and Z-scores (0.699-0.833). Relation of low BMD diagnosis in pediatric and adults was significant, and Kappa showed a moderate to good correlation between criteria for low BMD in childhood and adulthood, both with special significance in femoral region (8.10-14.47 and 0.258-0.703, respectively). Z-score ≤-2 significantly increased risk of low BMD in adulthood only when T-Score ≤-2.5 was used as low BMD criteria in adulthood (6.2-15.7). More patients dropped to poorer diagnosis group when Z-Score ≤-2.0 was used as low BMD criteria in adulthood. There is a moderate to good agreement of these criteria, at least in femoral region but using T-Score ≤-2.5 as low BMD criteria in adulthood caused a better prediction power for Z-Score ≤-2 of childhood.