Urinary iron excretion for evaluating iron chelation efficacy in children with thalassemia major.

Background: In patients with thalassemia major, examination routinely used for the evaluation of iron load in Indonesia is serum ferritin, but it is strongly influenced by other factors such as infections, inflammation and vitamin C levels. Evaluation of urinary iron excretion is an important and easy method to indicate iron chelation efficacy.

Objective: To determine the efficacy of iron chelation therapy by urinary iron examination and to evaluate its correlation with the time of transfusion, serum ferritin level, transferrin saturation and T2* MRI.

Methods: Prospective cohort study was conducted in children with thalassemia major aged 7-<18 years old who received DFP therapy. Twenty-four-hour urine collections were examined through inductively coupled plasma - mass spectrometry (ICP-MS). Patient's serum ferritin, transferrin saturation, peripheral blood, differential count and T2* MRI was documented during the study. Data analysis is based on urine iron level, body iron balance and the correlation between urine iron level, serum ferritin, transferrin saturation and T2* MRI and dosage of DFP.

Results: Thirty (55%) subjects showed a higher urine iron level on the day prior to transfusion (mean: 12,828 SD ±12,801 μg/24 h) in comparison to post transfusion (mean: 10,985 SD ±10,023 μg/24 h). All subjects had positive iron balance (mean 524 SD ±230 mg). There were positive correlation between urine iron level and transferrin saturation (r = 0.559, p = 0.01) and serum ferritin (r = 0.291, p = 0.03), no correlation found with T2* MRI results.

Conclusions: There is a relationship to urinary iron excretion in response to chelation therapy and the degree of iron load.