[CA-P control in haemodialysis and K/DOQI guidelines]

BACKGROUND: The publication in 2003 of the K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease recommended targets levels for serum iPTH, Ca, P, and CaxP product. However, many patients do not achieved these target ranges. It is necessary to known the percentage of patients out of range in order to prevent the development of bone disease and to reduce mortality and morbidity.

OBJECTIVES: To know the degree of control of Ca-P metabolism in haemodialysis patients in our haemodilalysis facilities and the achievement of target levels recommended by K/DOQI Guidelines.

PATIENTS AND METHODS: We have retrospectively investigated in 190 prevalent haemodialysis patients (males 58.2%, ratio M/F 1.4, mean age 70 years, range 17-87 years, at least 3 months in haemodialysis) the serum levels of Ca, albumin-corrected serum Ca, P, CaxP product and iPTH in all analitycal determinations performed in 2004. In each patient we have obtained the average (and median) of these serum markers. Cut-off levels were carried out following the recommendations of the K/DOQI Guidelines.

RESULTS: The average of serum Ca and albumin-corrected serum Ca is normal (means +/- SD = 8.9 +/- 0.6 mg/dL and 9.2 +/- 0.7 mg/dL, respectively); however, 53.7% has normal values, 9.1% hypocalcemia and 37.1% hypercalcemia. The average of serum P is also normal (mean +/- SD = 5.0 +/- 1.3 mg/dL); however, only 57.2% has normal values, and 11.7% has hypophosphoremia and the remaining 31, 1% hyperphosphoremia. The CaxP product is normal (mean +/- SD = 46.3 +/- 13.3 mg2/mL2), 4.9% with low values and 23.4% with high values. The median of serum iPTH is 253 pg/mL, but only 31.1% of them have normal values, 25.1% low range values and 43.7% has hyperparathyroidism; 9.3% with iPTH higher than 800 pg/mL. The percentage of patients with hyperphosphoremia is higher in the group with iPTH higher than 300 pg/mL (23.3% vs. 40%, chi2, p= 0.006). In patients with PTHi in normal range, 3.6% have low CaxP product and the remaining 17.8% high CaxP product. Overall, only 25% of patients falls within recommended ranges for all indicators of mineral metabolism and 17% has all serum markers outside these recommendations.

CONCLUSIONS: The degree of control of mineral metabolism in haemodyalisis patients if clearly insufficient and a large percentage of them do not achieved the recommended serum targets recommended by K/DOQI Guidelines. This groups of patients are exposed to a increased risk for oseous and cardiovascular morbimortality. The analysis of adequacy must be performed with percentage of patients out of range in order to apply new therapeutical strategies.