Parathyroid and bone response of the diabetic patient to uremia

Biochemical and radiologic indices of bone disease were assessed in 26 insulin-dependent diabetic patients and 28 nondiabetic patients with endstage kidney disease. The two groups were comparable in age, sex, duration of renal failure, and length of time on dialysis. Diabetic patients showed significantly lower serum calcium and immunoreactive parathyroid hormone (iPTH) levels than nondiabetic patients. iPTH was not related to total serum calcium, but was positively correlated with serum phosphorous (r = 0.37, P less than 0.05 and r = 0.54, P less than 0.005, in nondiabetic and diabetic patients, respectively). iPTH correlated with alkaline phosphatase (r = 0.59, P less than 0.0009) and calcitonin (r = 0.51, P less than 0.05) only in nondiabetic patients. Osteitis fibrosa was noted radiologically in 30% of nondiabetic patients and in none of the diabetic patients (P less than 0.03). Bone morphology in eight diabetic patients who underwent iliac bone biopsy was characterized by reduced trabecular and osteoid bone volume, no woven bone, and marked reduction in indices of bone formation and resorption. The small amount of bone and lack of osteomalacia are a unique feature of the diabetic patient with chronic renal disease. The long-term sequelae of low bone turnover and reduced circulating iPTH may present a special problem to the long term diabetic survivor on the current therapies of uremia.