Risk factors for reduced bone density in haemodialysis patients

Renal osteodystrophy may result in considerable morbidity for patients with end-stage renal disease. Secondary hyperparathyroidism, adynamic bone disease and osteomalacia, the main bony problems in chronic renal failure, may all be responsible for a reduction in bone mineral density (BMD). This can result in an increased fracture risk. By virtue of their age, post-menopausal status (in women), sedentary life-style and treatment (including previous corticosteroids), haemodialysis patients may be expected also to be at risk for developing osteoporosis, but little is known about the relative importance of these factors.

We report a prospective study examining the prevalence of reduced bone mineral density (BMD) and its association with a wide range of factors, in a heterogenous group of 88 chronic haemodialysis patients. Femoral neck and lumbar BMD were measured by dual-energy X-ray absorptiometry (DXA). Stepwise multiple linear regression analysis was used to identify risk factors associated with low bone mass.

Forty three patients (48.9%) had reduced BMD, and in 17 (19.3%) BMD was below the fracture threshold as defined on DXA measurements by the World Health Organization (WHO). The BMD had significant negative associations with age, serum parathyroid hormone (PTH) levels, current gastric acid suppression therapy, female gender, age at menarche and history of previous fracture. Positive associations were found with weight, haemoglobin concentration, average serum phosphate, weekly heparin dose, oral calcium supplementation and history of parathyroidectomy.

We have confirmed the importance of PTH-related bone disease in affecting BMD in haemodialysis patients, but have found that some other factors, which are known to be risk factors for osteoporosis, are also important.