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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.