Secondary hyperparathyroidism and calcium phosphate control in a hemodialysis population

To evaluate the prevalence of secondary hyperparathyroidism and calcium phosphate control in the hemodialysis Asian population.

We evaluated 36 patients at Tan Tock Seng Hospital in Singapore, who were receiving thrice weekly maintenance hemodialysis for at least 6 months. Patients with history of previous parathyroidectomy were excluded from the study. Patient's weight, length of dialysis per week, duration of dialysis, serum calcium, phosphate, albumin, bicarbonate, intact parathyroid hormone (iPTH), and single pool Kt/V were retrieved from patient's medical records.

The mean length of weekly dialysis session and single pool Kt/V was 13.5 hours and 1.73 respectively. The majority of patients achieved the target range of serum phosphorus (67%), corrected calcium (58%) and calcium times phosphate (Ca ' P) product (81%). Only 25% of patients had levels of iPTH within the target range (150-300 pg/mL). Ninety four percent of the patients were on calcium-based phosphate binder and 42% on vitamin D therapy. A significant number of patients still fell out of the recommended guideline range for serum concentrations of phosphorus (11% of patients below lower target range, 22% of patients above upper target range), corrected calcium (3% below, 39% above), calcium-phosphorus product (19% above), and iPTH (58% below, 17% above). Thirty percent of the patients had levels of iPTH < 100 pg/mL.

Compared to data reported from the USA, Europe and Japan, mean levels of phosphate, corrected calcium and Ca ' P product seem better controlled in this hemodialysis Asian population. However, more than half of the patients may have oversuppression of iPTH levels and a third of patients are at increased risk of developing a dynamic bone disease.