Achieving K/DOQI laboratory target values for bone and mineral metabolism: an uphill battle

The National Kidney Foundation has recently published the Kidney Disease Outcomes Quality Initiative (K/DOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease (CKD). According to these guidelines, in patients with stage 5 CKD, the adjusted calcium level should be 8.4- 9.5 mg/dl, the serum phosphate should be 3.5-5.5 mg/dl, the calcium phosphorous product should be <55 mg(2)/dl(2) and the intact parathyroid hormone (PTH) level should be 150-300 pg/ml.

In order to evaluate our ability to meet these targets, we reviewed laboratory parameters of bone and mineral metabolism of 140 patients over a 6-month period in an inner city hemodialysis unit. Serum calcium and phosphate levels were determined using standard assays and PTH levels were determined using the Nichols Intact PTH assay.

We found that the levels of serum calcium and serum phosphorus fell within the range recommended by the K/DOQI guidelines 49 and 36% of the time respectively. 57% of the determinations for calcium x phosphorus product were <55 mg(2)/dl(2). PTH levels were within the recommended values in 20% of the determinations. Only 7% of the determinations met all four criteria simultaneously in spite of meeting other K/DOQI targets such as hematocrit and dialysis adequacy.

These data indicate that current practice for the management of bone and mineral metabolism in hemodialysis falls far short of meeting the K/DOQI guidelines.