Evaluation of bone mineral density in CAPD patients with dual energy X-ray absorptiometry

In this study bone mineralization was evaluated using dual energy x-ray absorptiometry (DEXA), which measured regional bone mineral density [BMD (g/cm2)] at two skeletal sites, the lumbar spine and the femur, in 33 patients (15 male, 18 female) undergoing continuous ambulatory peritoneal dialysis (CAPD) with no history of chronic disease or medications affecting bone. The biochemical profile included measurements of plasma levels of calcium, phosphorus, alkaline phosphatase, and intact parathyroid hormone (iPTH). We did not find any statistically significant difference or correlation between BMD and the examined parameters, except for the lower BMD values in the female population. Because of the reported findings of significantly lower PTH levels in CAPD patients with low turnover bone disease (adynamic bone disease) and the higher prevalence in CAPD than in hemodialysis patients, we tried to evaluate any correlation between BMD and iPTH levels in CAPD patients that were separated into two groups: group A (iPTH < 200 pg/mL), 13 patients, and group B (iPTH > 200 pg/mL), 20 patients. Data analysis revealed a negative correlation between PTH levels and BMD values (r = -0.66, p = 0.014) as PTH and serum calcium (r = -0.77, p = 0.002) only in group A. No other statistically significant changes were observed. These findings suggest that there is a favorable influence of CAPD modality on bone mineralization, while no special DEXA findings are representative of the possible appearance of adynamic bone disease.