Renal Insufficiency and Secondary Hyperparathyroidism in Elderly Patients

Abstract

Glomerular filtration rate (GFR) is frequently reduced in elderly people. However, the effect of this on mineral metabolism in this population has received little attention. GFR, serum intact parathyroid hormone (PTH) and vitamin D metabolites were measured in 37 patients admitted to hospital for various reasons. In 20 patients with GFR > 50 mL/min, an elevated serum intact PTH concentration (> 5 · 4 pmol/L) was found in two, while in 17 patients with GFR < 50 mL/min PTH was elevated in 13. One of this group was hypercalcaemic and presumed to have primary hyperparathyroidism. Adjusted calcium was normal in all other patients. Two patients had a low serum 25-hydroxyvitamin D concentration (<9 nmol/L) suggesting vitamin D insufficiency while a further five had a reduced 1,25-dihydroxyvitamin D concentration, four of these having a GFR < 50 mL/min. We conclude that hyperparathyroidism is common in hospitalized elderly patients, particularly in those with mild to moderate renal insufficiency. This may contribute to bone mineral loss in such patients.