Aluminium-containing agents may be toxic in predialysis chronic renal insufficiency patients

Objective. To investigate the possible toxic effects of long-term low dose aluminium (Al) exposure in predialysis chronic renal insufficiency (CRI) patients (serum creatinine > 1.4 mg dL^-1). Design. An open, random, and prospective clinical study. Setting. The study was carried out at Chang Gung Memorial Hospital, a medical centre of Chang Gung Medical College. Subjects. Seventy CRI patients who have regularly attended a nephrology out-patient department participated in this study. After a 3-month wash-out period 50 were given an Al loading test and 20 received no Al-containing agents. Interventions. We used a low dose of AI(OH)₃ (one tablet three times day^-1, about 302 mg aluminium day^-1) for 3 months as an Al loading test. Main outcome measures. The study was divided into two phases: phase 1, a basal study to measure serum Al, iron, ferritin, daily urinary Al excretion and renal function status: and phase 2, in which an Al loading test was performed. The phase 1 parameters were measured again after the Al loading test to compare the differences between pre- and post-study in the two groups. Results. We found significant increments of serum Al and daily urinary Al excretion in all study group patients after the Al loading test. The increments of serum Al correlated with basal creatinine clearance (Ccr: r = -0.352, P < 0.05) and basal serum ferritin (r = -0.302, P < 0.05). Serum ferritin was significantly reduced after the Al loading tests, and the reduction (r = 0.357, P < 0.05) positively correlated with the increments of daily urinary Al excretion in the study group patients. However, no significant changes of serum Al, ferritin, and daily urinary Al excretion were noted in the control group patients. Conclusions. A long-term low dose Al exposure can cause significant Al accumulation and iron store depletion in CRI patients. Therefore, Al-containing agents should be used with caution in patients with CRI.