Incidence of deferasirox-associated renal tubular dysfunction in children and young adults with beta-thalassemia

Abstract

Renal tubular dysfunction has been reported in patients on deferasirox therapy but no systematic study has been performed. This study aimed to determine the cumulative incidence of renal tubular dysfunction and serum electrolyte imbalances among children and young adults with transfusion-dependent beta-thalassaemia on deferasirox and study their intermediate term outcomes. Mean age was 15.89 years (range: 2.6-24.10 years). Nine (50.0%) patients were on deferasirox, three (16.7%) were on deferoxamine, two (11.1%) were on deferiprone, and four (22.2%) were on combination deferiprone and deferoxamine. Twelve (66.7%) patients had renal tubular dysfunction, defined by elevated urine -2 microglobulin, of whom nine were on deferasirox. Eight patients (44.4%) had concomitant serum electrolyte imbalance, all of whom were on deferasirox. Compared to those on other chelation regimens, patients on deferasirox were more likely to develop renal tubular dysfunction (OR 35.3, p=0.009), hypokalaemia (OR 23.2, p=0.015), hypophosphataemia (OR 57.0, p=0.001), hypocalcaemia (OR 23.2, p=0.015), and Fanconi syndrome (OR 15.6, p=0.004). Cumulative incidence of renal tubular dysfunction was estimated to be 89% at 6 years of deferasirox therapy. These effects were reversible with suspension or dose reduction of deferasirox. Vigilant monitoring of renal tubular dysfunction and serum electrolyte is recommended in patients who receive deferasirox.