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

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

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).

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.

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.