Hyperparathyroid bone disease in diabetic renal failure.

Hyperparathyroid bone disease is a common complication of end stage renal failure, particularly in patients on maintenance haemodialysis. Several studies have, however, shown a near absence of hyperparathyroid bone disease in diabetic patients who have been receiving haemodialysis for periods of up to 4 years. We have studied biochemical indices of mineral metabolism in 54 consecutive pre-dialysis patients with moderate to severe renal impairment. Deteriorating renal function was associated with developing hypocalcaemia and hyperphosphataemia. Hypocalcaemia was strongly related to increased severe alkaline phosphatase activity (p less than 0.001), suggesting the development of hyperparathyroidism. Five patients with hypocalcaemia and increased alkaline phosphatase were studied in detail. All had elevated serum concentrations of parathyroid hormone and histological signs of hyperparathyroidism on bone biopsy. Three of the patients had low serum 25 hydroxyvitamin D levels with associated osteomalacia, the other 2 patients were notable for their long duration of renal failure. In the long-term (greater than 4 years) we also observed the development of hyperparathyroidism in a small group of diabetic patients maintained on haemodialysis. We conclude that diabetic patients are not uniquely protected against renal osteodystrophy. Although the prevalence of hyperparathyroidism may be lower in diabetic patients than in those with other types of renal disease, the same factors which predispose to bone disease in non-diabetic patients (long duration of renal failure, low serum 25 hydroxyvitamin D and long periods on haemodialysis) also operate in the diabetic population.