New study findings suggest that maintaining low levels of parathyroid hormone (PTH) in hemodialysis (HD) patients who underwent parathyroidectomy may decrease the risk of dying from cardiovascular causes.

A team led by Noriyuki Iwamoto, MD, of Tojinkai Hospital in Kyoto, Japan, studied 295 HD patients who underwent parathyroidectomy without autotransplantation. They divided patients into high and low PTH groups using a median intact PTH (iPTH) value after surgery of 16.6 pg/mL. The high PTH group (iPTH levels of 16.6 pg/mL or higher) included 147 patients, and the low PTH group (iPTH levels below 16.6 pg/mL) included 148 patients. Investigators followed up patients for 5 years.

The overall survival rate was lower in the high PTH group than the low PTH group (54.9% and 74.2%, respectively), but the difference was not significant; the cardiovascular survival rate, however, was significantly lower in the high PTH group (71.6% vs. 94.4%), Dr. Iwamoto and colleagues reported online in Clinical and Experimental Nephrology. In adjusted analyses, an iPTH of 16.6 pg/mL or higher was associated with a significant 3-fold increased likelihood of cardiovascular death compared with lower iPTH values.

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The researchers noted that the rate of extirpation of more than 4 parathyroid glands was significantly lower in the high PTH than low PTH group (58.5% vs. 92.6%).

The high and low groups did not differ significantly in mean age (59.3 vs. 58.3 years, respectively), gender composition (51.7% and 53.4% male, respectively), and dialysis vintage (158.4 and 154.5 months, respectively).