Dietary and pharmacotherapeutic considerations in the management of renal osteodystrophy

Academy of Nutrition and Dietetics Commentary on the Phosphorus Recommendation in the KDOQI Clinical Practice Guidelines for Nutrition in CKD: 2020 Update

The Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Nutrition in Chronic Kidney Disease: 2020 Update recommends adjusting dietary phosphorus to maintain a serum phosphate goal for hemodialysis patients in the normal range (0.81 to 1.45 mmol/L [2.5 to 4.5 mg/dL]). This is lower than the serum phosphate goal used by many dialysis centers (0.97 to 1.78 mmol/L [3.0 and 5.5 mg/dL]). Although context and clinical judgment must always be considered when providing individualized care to patients, a guideline implementation study conducted from December 2020 to December 2022 found that, based on their documentation, registered dietitian nutritionists from two national dialysis chains are almost universally using dialysis center goals instead of the lower phosphate goal recommended by the guideline. This commentary discusses the possible barriers to implementing the Kidney Disease Outcomes Quality Initiative 2020 nutrition guideline's phosphorus recommendation and proposes a systems level approach to promote and support adoption of the recommendation. Calls to action for potential changes in clinician practices, organizational/institutional culture, and government regulations are put forth.

Relationship between serum phosphorus levels and various outcome measures in adult hemodialysis patients

OBJECTIVE

To compare three different mean serum phosphorus ranges on outcomes related to the control and treatment of hyperparathyroidism (HPTH), to nutritional status, and to quality of life (QOL) in adult hemodialysis (HD) patients.

DESIGN

Patients were grouped based on the mean of five monthly phosphorus levels achieved during the study period. Group 1 included patients whose mean phosphorus levels over the period was <6.0 mg/dL (n = 24); group 2 averaged between 6.0 and 6.9 mg/dL (n = 14); and group 3 averaged >7.0 mg/dL (n = 16). Descriptive comparisons were made between phosphorus groups.

PATIENTS

Fifty-four stable, adult HD patients participated voluntarily.

MAIN OUTCOME MEASURES

Intact-parathyroid hormone (iPTH), calcium x phosphorus product (Ca x P), and change in iPTH, albumin (alb), total protein (tpro), weight (wt) and body mass index (BMI), and scores on a QOL survey. Baseline physical and lab characteristics.

RESULTS

No difference was found between phosphorus levels of <6.0 mg/dL and levels of 6.0 to 6.9 mg/dL in iPTH, Ca x P levels allowing safe calcitriol therapy, nor response to calcitriol treatment. Patients with phosphorus levels >7.0 mg/dL had midstudy iPTH greater than phosphorus levels <6.0 mg/dL. Otherwise the three groups did not differ significantly in iPTH levels. Phosphorus levels 6.0 to 6.9 mg/dL was associated with lowest wt and BMI, but alb and tpro did not differ between the phosphorus groups. Phosphorus levels of >7.0 was associated with highest creatinine levels and youngest age. Subjects in the phosphorus levels of <6.0 mg/dL gp were more likely than the 6.0 to 6.9 mg/dL gp to describe their diet as sufficient and, at baseline, were more likely to relate diet to QOL.

CONCLUSION

Comparison of three levels of serum phosphorus on indicators of outcome in the control and treatment of secondary hyperparathyroidism showed no significant difference in outcome between phosphorus levels of <6.0 mg/dL and phosphorus levels 6.0 to 6.9 mg/dL. However, the data suggests that phosphorus levels of >7.0 mg/dL may relate to significantly higher iPTH and unacceptable Ca x P levels. There were no differences between the groups, suggesting less favorable outcome at any of the three phosphorus levels regarding nutritional status or QOL in this small group of stable, adult HD patients.