Monthly Monitoring of Parathyroid Hormone May Be Optimal
Suneeta Gadde, MD
Because secondary hyperparathyroidism is a common manifestation of CKD, guidelines from the Kidney Disease Outcomes Quality Initiative (KDOQI) suggest monitoring PTH levels in HD patients every three months. Many dialysis centers, however, routinely monitor PTH levels monthly without any data to support this protocol.
Suneeta Gadde, MD, and her colleagues conducted a study to determine the optimum frequency of monitoring PTH levels in 150 patients on maintenance HD. All the patients were from a single center (Maimonides Medical Center in Brooklyn, N.Y.) and were treated between February 2008 and March 2009. In phase 1 of the study, the researchers measured PTH levels every three months. In phase 2, the monitoring was done monthly. When PTH levels were out of the target range, clinicians appropriately adjusted diet, phosphorus binders, vitamin D analogues, and calcimimetics as per standard protocols.
For this study, the primary end point was the percentage of patients achieving PTH levels within the KDOQI target range of 150-300 pg/mL. The secondary endpoints were calcium (Ca) and phosphorus (P) levels in target range (8.4-9.5 mg/dL for Ca and 3.5-5.5 mg/dL for P).
The percentage of patients with PTH in target range increased significantly from phase 1 to phase 2 of the study (from 25.4% to 40.3%). Additionally, researchers observed a significant drop in the percentage of patients with PTH levels greater than 300 pg/mL in phase 2 compared with the national average (37% vs. 47%). The percentage of patients with Ca and P levels in normal range were similar in phase 1 and 2.