Serum uric acid of patients with beta-thalassemia major (b-MA), despite the hyperuricosuria observed in these patients, is usually in the upper normal levels or increased due to excessive catabolism of the red blood cells (ineffective erythropoiesis). Deferasirox a new oral iron chelator with potential nephrotoxicity is recently used as iron overload treatment in patients with b-MA.
Aim of the study is to investigate the effect of deferasirox on uric acid levels of patients with homozygous b-MA.
53 patients were enrolled to the present study with b-MA major, (aged 22.4 ± 14.7 years, range 4–12 years) 36 adults and 17 children, 32 females and 21 male. All the patients were transfusion-dependent with pretransfusional haemoglobin 9gr/dl and treated with iron chelation. The comparison was made between two different time points' measurements of uric acid and ferritin, at the beginning before Deferasirox, and one year later. The blood was taken from the patients early at mornings before the transfusion. Also uric acid was measured in 24 hour urine of patients under deferasirox, or other iron chelation therapy or after weekly discontinuation of deferasirox. Patients taken allopurinol or thiazide or with abnormal kidney function were excluded.
There is statistically significant difference (p< 0.001) between the mean annual value of serum uric acid (before 5.2 ± 1.3mg/dl) and ferritin (before 1653,4 ± 1026,3 ng/dl) before and after the start of deferasirox (uric acid after 4.2 ± 1.3 mg/dl and ferritin after 1529,07 ± 1137,44 ng/dl). Also, statistically significant positive correlation between the levels of serum uric acid and ferritin was found during the treatment with deferasirox. However, comparing the uric acid in urine of patients, it was not reported any statistically significant difference between treatment with deferasirox (859,75 ± 122), other iron chelators or without iron chelation for one week (844,32 ± 146).
The mechanism of uric acid reduction in patients with b-MA major treated with deferasirox is not clear. However, it does not seem to be associated with excess of excretion by urine. The positive correlation between uric acid level and ferritin, allow us to consider uric acid as a predictor factor of the response to deferasirox therapy.
Vlachaki:Novartis Hellas S.A.C.I.: Research Funding. Oikonomou:Novartis Hellas S.A.C.I.: Research Funding.
Asterisk with author names denotes non-ASH members.