RENAL OSTEODYSTROPHY IN DIABETIC-PATIENTS

To assess the effects of diabetes mellitus on renal osteodystrophy, we examined the database of 256 patients (45% on hemodialysis and 55% on peritoneal dialysis) who were prospectively studied in three Toronto dialysis centers between October of 1987 and 1989. All patients had se rial documentation of their clinical, laboratory and risk parameters o f bone disease, and completed a series of investigations that included the deferoxamine test, measurement of intact 1-84 PTH levels, and an iliac crest bone biopsy. Twenty-five percent of these patients were di abetic. When compared to non-diabetic patients, they were on dialysis for a shorter duration (2.4 +/- 0.3 vs. 4.7 +/- 0.3 years; P < 0.0002) , used calcium carbonate as the only phosphate binder more frequently (40 vs. 25%; P < 0.007), and had lower parathyroid hormone levels (12 +/- 1.4 vs. 24 +/- 2.3 pmol/liter; P < 0.002). High-turnover bone diso rders (that is, osteitis fibrosa and mixed disorder) were distinctly u ncommon (8 vs. 33%; P < 0.01 by Fisher's exact test), while the mild ( 19 vs. 9%; P = NS) and the aplastic disorders (with mean stainable bon e surface aluminum of 6.5 +/- 0.7%) (46 vs. 31%; P = NS) tended to be more common in diabetic patients. The prevalence of aluminum bone dise ase was the same in both groups (27%). Diabetic patients ingested a sm aller cumulative dose of aluminum gels (3.7 +/- 0.6 vs. 9.3 +/- 1. 1 k g; P < 0.005), yet had a higher rate of aluminum accumulation on bone surfaces than non-diabetic patients (1.5 +/- 0.19 vs. 0.96 +/- 0.10% p er month on dialysis; P < 0.015). Although the cumulative exposure to aluminum gels remained the major risk factor for aluminum bone disease (P < 0.0001), a positive interaction was noted for diabetic mellitus to increase this risk (P < 0.05). Thus, diabetes mellitus appears to p redispose dialysis patients to low bone-turnover states. In addition, it appears to increase aluminum accumulation on bone surfaces and pred isposes to aluminum bone disease. The clinical significance of the apl astic disorder remains to be defined.