Low-calcium dialysate as a risk factor for decline in bone mineral density in peritoneal dialysis patients.

Objective: Few studies have linked changes in bone mineral density (BMD) in peritoneal dialysis (PD) patients to the calcium concentration in peritoneal dialysate.

Material and methods: In total, 236 incident patients who underwent an annual BMD determination for 2 years were enrolled. The patients were divided into two groups: the standard calcium dialysate (SCD) group (n = 190; 1.75 mmol/l) and the low-calcium dialysate (LCD) group (n = 46; 1.25 mmol/l).

Results: There were no significant differences between the baseline demographics of the two groups, such as age, diabetes, calcium, phosphorus, alkaline phosphatase (ALP), intact parathyroid hormone (i-PTH) levels or variables related to BMD. Univariate and multivariate analyses [adjusted for age, gender and time-averaged 25(OH)-vitamin D] determined that the LCD group had higher time-averaged i-PTH and ALP and a greater decrease in bone mineral content, lumbar spine BMD, subtotal BMD and total BMD compared to the SCD group.

Conclusion: LCD is associated with a more rapid decline in BMD, higher i-PTH and higher ALP in PD patients. It is suggested that LCD be avoided for PD patients at risk of osteoporosis and hyperparathyroidism.