关键词:

输血依赖型地中海贫血, 铁过载, 血清铁蛋白, 骨代谢, 儿童

Abstract:

Objective　To investigate and analyze the iron overload and bone metabolism in children with transfusion-dependent thalassemia (TDT). Methods　A total of 93 children with TDT admitted to Dongguan Eighth People's Hospital from January 2021 to August 2023 were selected as the research subjects. The severity of iron overload was determined based on the serum ferritin (SF) level and the children were divided into three groups: children without iron overload (SF ≤1 000 μg/L, 14 cases), children with mild to moderate iron overload (1 000 μg/L < SF < 2 500 μg/L, 32 cases), and children with severe iron overload (SF ≥2 500 μg/L, 47 cases). There were 7 boys and 7 girls in the non-iron overload group, with an age of (7.14±1.29) years old. In the mild to moderate iron overload group, there were 17 boys and 15 girls, with an age of (7.10±1.12) years old. In the severe iron overload group, there were 19 boys and 28 girls, with an age of (7.44±1.45) years old. All children with iron overload received iron removal treatment. The levels of SF, bone metabolism indicators {parathyroid hormone (PTH) and serum 25-hydroxyvitamin D₃ [25(OH)D₃]}, and liver function indicators [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)] in children with mild to moderate and severe iron overload were compared before and 3 months after medication. Pearson correlation analysis was used to investigate the correlations between the SF level and bone metabolism indicators in children with iron overload. Multivariate logistic regression analysis was conducted to identify the independent risk factors for severe iron overload in children with TDT. Statistical analysis was conducted using the χ² test, Fisher's exact probability method, independent sample t test, and one-way analysis of variance. Results　The levels of SF, PTH, ALT, and AST before medication and SF after medication in the severe iron overload group were (5 410.74±930.15) μg/L, (9.57±1.79) pmol/L, (45.50±8.47) U/L, (65.88±8.19) U/L, and (3 197.13±629.49) μg/L, which were all higher than those in the mild to moderate iron overload group [(1 801.53±388.21) μg/L, (6.17±1.23) pmol/L, (37.45±8.80) U/L, (54.74±6.75) U/L, and (1 225.62±199.48) μg/L] (all P<0.05); the level of 25(OH)D₃ before medication in the severe iron overload group was (18.22±4.48) μg/L, which was lower than that in the mild to moderate iron overload group [(24.86±5.48) μg/L] (P<0.05). The Pearson correlation analysis results showed that before treatment, the SF level was negatively correlated with the 25(OH)D₃ level (r = -0.561, P<0.05), and positively correlated with the PTH, ALT, and AST levels (r = 0.646, 0.392, and 0.544, all P<0.05); after treatment, the SF level was negatively correlated with the 25(OH)D₃ level (r = -0.484, P<0.05), and positively correlated with the PTH, ALT, and AST levels (r = 0.623, 0.342, and 0.448, all P<0.05). The logistic regression analysis results showed that pre-medication high PTH (OR = 3.914, 95%CI = 2.168 - 7.065), low 25(OH)D₃ (OR = 0.755, 95%CI = 0.659 - 0.864), high ALT (OR = 1.114, 95%CI = 1.048 - 1.184), and high AST (OR = 1.203, 95%CI = 1.108 - 1.307) were all independent risk factors for severe iron overload in children with TDT (all P<0.05). Conclusions　Iron overload is common in children with TDT in Dongguan, and the severity of iron overload is correlated with bone metabolism disorders. It is recommended to include bone metabolism markers in routine monitoring of TDT children and initiate early combined iron removal therapy for those with SF >2 500 μg/L.

Key words:

Transfusion-dependent thalassemia, Iron overload, Serum ferritin, Bone metabolism, Children