Effects of Dietary Phosphorus on Phosphorus and Calcium Whole-Body Balance and Kinetics in Moderate CKD

Launched by UNIVERSITY OF MINNESOTA · Nov 26, 2024

Keywords

ClinConnect Summary

This clinical trial is looking at how different levels of dietary phosphorus affect the balance of phosphorus and calcium in people with moderate chronic kidney disease (CKD). The study will involve 22 participants who will follow two different diets—one low in phosphorus and one high in phosphorus—over a period of 21 days each. Participants will spend some time on an outpatient diet and also some time in the hospital for controlled studies to understand how their bodies process these nutrients.

To be eligible for this study, participants must be men or women aged 30 to 75, have moderate CKD, and have specific levels of parathyroid hormone in their blood. They should not be planning to start dialysis soon, and certain health conditions or medications may exclude them from participating. Throughout the trial, participants will follow a controlled diet and monitor their health closely, helping researchers learn more about how phosphorus in our food can impact kidney health.

Gender

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Eligibility criteria

• Inclusion Criteria:
• • Men or women, ages 30-75 years old, any race or ethnicity
• • Moderate CKD, defined by KDIGO as eGFR category 3b (30-44 mL/min) or 4 (16-29 mL/min) with albuminuria categories A1-A3
• • Serum intact parathyroid hormone above assay normal limit
• • Female subjects must be postmenopausal (\>12 months since last menstrual period), surgically sterile, or confirmed not pregnant by pregnancy test
• • Must be on stable doses of medications (except those noted in exclusion criteria) for at least 4 weeks prior to the study
• • Willing to discontinue supplements (e.g., vitamin D, calcium, multivitamin/minerals, or others) upon enrollment until completion of the study
• • Adequate vitamin D status defined as serum 25D \> 20 ng/mL based on National Academy of Medicine (then Institute of Medicine) criteria.
• Exclusion Criteria:
• • Plans to initiate dialysis within 6 months
• • Hypercalcemia defined as corrected serum calcium \>9.8 mg/dL within past 3 months
• • Hyperkalemia defined as serum potassium \>5.5 mg/dL within past 3 months
• • Hyperphosphatemia defined as serum phosphate \>5.5 mg/dL within past 3 months
• • Intestinal disease that alters absorption or normal intestinal function including celiac disease, small bowel resection, bariatric surgery, or chronic diarrhea/malabsorption
• • Serious, uncontrolled underlying systemic disease including diabetes, lupus, hypertension in the opinion of their physician
• • Pregnant or breastfeeding
• • Prescribed and taken a phosphate binder medication, calcitriol, vitamin D analogs, calcimimetics, PTH analogues, and other medications that may alter Ca and P metabolism within past 4 weeks
• • Non-English speaking