Adherence to K/DOQI guidelines for calcium-based phosphate binders in clinical practice.

Objective: The Kidney Disease Outcomes Quality Initiative (K/DOQI) clinical practice guidelines for bone metabolism in chronic kidney disease recommend that calcium-based phosphate binders (CBPBs) be used in limited doses and be reduced or withheld when albumin-adjusted serum calcium exceeds target values, or when parathyroid hormone is below the target range. We sought to assess the pattern of CBPB use in a clinical practice setting.

Design: This was a retrospective review.

Patients: We reviewed 283 patients at three hemodialysis units in New York and New Jersey in which 39 physicians practice.

Methods: Data collected included intact parathyroid hormone levels (from February and May, 2006), blood chemistries (from April and May, 2006), and the use of CBPBs, vitamin D, and cinacalcet. The use of CBPBs was classified as "consistent" or "inconsistent" with the guidelines 1 month after the blood tests of May 2006 (to allow time for dosing adjustments). Because cinacalcet was not available when the K/DOQI guidelines were published, a failure to reduce or stop CBPBs in the presence of elevated calcium levels was still considered to be "consistent" use if cinacalcet was initiated in the appropriate time frame (5 patients).

Results: CBPBs were used in 172 of 283 patients (61%). In 10% (17 patients), doses exceeded the 1500-mg limit for calcium. Adjusted serum calcium levels exceeded 2.5 mmol/L (10.2 mg/dL) in 8 cases; CBPBs were not reduced or stopped in any of these. Similarly, CBPBs were reduced in only 2 of 27 patients on vitamin D, with an adjusted serum calcium level of 2.38 to 255 mmol/L (9.5 to 10.2 mg/dL). In all 10 patients with consecutive intact parathyroid hormone values of less than 150 ng/L (150 pg/mL), CBPBs were not discontinued or reduced.

Conclusions: Overall, 50 of 172 patients (29%) receiving CBPBs did so in a manner inconsistent with K/DOQI guidelines. The reasons for this inconsistency are speculative, and may include disagreement with the opinion-based recommendations, insufficient knowledge of the guidelines, or individual patient considerations (including cost, tolerance, and effectiveness).