Risk Factors for Hyperaluminemia in Continuous Ambulatory Peritoneal Dialysis

Abstract

The authors evaluated risk factors for hyperaluminemia and aluminum toxicity in 51 CAPD patients, who received aluminum-containing phosphate binders. Serum aluminum correlated with total intake of elemental aluminum after starting CAPD (p = 0.001), with aluminum intake in the previous six months (p = 0.001), with duration of CAPD (p = 0.003), and with serum phosphate (p = 0.05). Eight patients had elevated serum aluminum, but only one had clincial evidence of aluminum toxicity (he had been on hemodialysis with untreated water until he was changed to CAPD 30 months before the study). Although the incidence of clinical aluminum toxicity appears to be low, we conclude that the aluminum intake from aluminum-containing phosphate binders is a major factor in the evolution of hyperaluminemia and, potentially, aluminum toxicity in CAPD patients. We believe that alternative effective, phosphate binders are much needed. It has been shown that tissue accumulation of aluminum in brain, bone and blood in uremic patients causes encephalopathy (I. 2), osteomalacia (3, 4), and anemia (5, 6). Clinically aluminum toxicity has been observed mainly in hemodialysis patients (1–6), although it has been reported in few cases before dialysis (7–9) and in those on continuous ambulatory peritoneal dialysis (10. II). The major cause of aluminum toxicity during hemodialysis has been transfer of aluminum from untreated water in the dialysate (1–5); this mechanism has tended to obscure the contribution of other factors, such as diet and drugs. Peritoneal dialysate contains a low concentration of aluminum (less than 15 μg/L) and there is a net removal of aluminum in the dialysate in those with serum aluminum levels within the reference range for dialysed uremics (11–13). Serial aluminum levels in CAPD patients not receiving aluminum -containing phosphate binders (ACPB) showed no significant change during a two-year follow-up (12, 14); this suggests that aluminum removal in the dialysate compensates for the failure of the kidney to excrete absorbed dietary aluminum in end-stage renal disease. Since the combination of CAPD and diet appears to have minimal influence on serum aluminum, this study was done to identify those factors which determine serum aluminum levels in CAPD patients, receiving aluminum-containing phosphate binders.