Do serum aluminum levels reflect underlying skeletal aluminum accumulation and bone histology before or after chelation by deferoxamine?

Patients undergoing dialysis may accumulate tissue aluminum burdens, and are at risk of developing two aluminum-associated syndromes, namely dialysis osteomalacia and encephalopathy. We address the clinical usefulness of serum aluminum levels in the diagnosis of dialysis osteomalacia. Twenty-four patients, 15 with dialysis osteomalacia and nine with clinically apparent secondary hyperparathyroidism, had serum aluminum levels measured before and after a standard infusion of a chelating agent, deferoxamine (DFO). Baseline serum aluminum levels were regarded as "high" (greater than 133 micrograms/L) if they exceeded 1 SD above the mean (74 micrograms/L) for a larger population of 152 patients undergoing routine hemodialysis. All patients had a bone biopsy for assessment of aluminum deposits by a specific histochemical stain. High serum aluminum levels had a diagnostic sensitivity of 60% in predicting those patients ultimately shown to have dialysis osteomalacia associated with histochemical evidence of aluminum accumulation in bone biopsy specimens; however, 40% of patients with histologic evidence of dialysis osteomalacia would have been missed if only serum aluminum had been used as a diagnostic test. Serum aluminum levels (+/- SEM) were 194 +/- 31 micrograms/L in patients with dialysis osteomalacia and 120 +/- 42 micrograms/L in those with secondary hyperparathyroidism (P greater than 0.05). Serum aluminum levels rose in all patients after DFO infusion to peak levels of 664 +/- 110 and 514 +/- 90 micrograms/L in patients with osteomalacia and hyperparathyroidism, respectively. However, neither the peak serum aluminum level nor its increment after DFO infusion distinguished between patients with osteomalacia and secondary hyperparathyroidism more effectively than did the baseline serum aluminum level.(ABSTRACT TRUNCATED AT 250 WORDS)