Degree and Course of Skeletal Demineralization in Patients with Chronic Renal Insufficiency

Abstract

To Study the degree and course of skeletal demineralization in patients with chronic renal failure gamma-ray bone densitometry of the radius was performed (1) in a cross-sectional study of 88 uremic patients and (2) in a longitudinal study over 13.5 months in 26 of these patients. The results were compared to measurements of bone mineral content/width (BMC/W) in 191 normal adults. Furthermore to evaluate the importance of calcium-metabolic changes in skeletal demineralization of uremic patients measurements of serum ionized calcium (Ca⁺⁺), phosphate, alkaline phosphatase, immunoreactive parathyroid hormone (i-PTH), intestinal calcium absorption, skeletal X-ray and ^99mTechnetium-polyphosphate bone scintigraphy were performed in the majority of the patients. An accelerated bone loss (mean 3.1% per year) was demonstrated in uremic patients together with a significant reduction in BMC/W. The duration of uremia was correlated with the BMC/W values, whereas dialysis treatment as such did not affect BMC/W. The most rapid demineralization occurred in patients with severe hypocalcemia and increased levels of alkaline phosphatase and i-PTH. The presence of bone pain and generalized scintigraphic bone changes of renal osteodystrophy were correlated with BMC/W while radiographic bone changes were not correlated with the degree of skeletal demineralization. It is concluded that osteopenia develops and deteriorates during the course of chronic renal failure. The most severe bone loss is predominantly found in uremic patients with clinical symptoms, generalized scintigraphic bone changes and major disturbances in calcium metabolism.