Effects of Dietary Phosphorus on Phosphorus and Calcium Whole-Body Balance and Kinetics in Moderate CKD
概览
- 阶段
- 不适用
- 干预措施
- LP then HP
- 疾病 / 适应症
- CKD
- 发起方
- University of Minnesota
- 入组人数
- 14
- 主要终点
- Phosphorus Balance
- 状态
- 尚未招募
- 最后更新
- 上个月
概览
简要总结
The aim of the study is to look at the effects of dietary phosphorus on phosphorous and calcium whole-body balance and kinetics in moderate chronic kidney disease (CKD). N = 14 enrolled subjects will be randomly assigned to a cross-over order of (A) Low P Diet, High P Diet. Each cross-over phase will be 19 days and consist of a 7-day outpatient, controlled diet period, followed by a 5- day inpatient, controlled diet, balance, and kinetic study period, followed by a second 7-day outpatient, controlled diet period.
详细描述
Chronic kidney disease (CKD) affects approximately 37 million (1 in 7) U.S. adults, most of whom experience mineral and bone disorders (CKD-MBD) that increase risk for cardiovascular events, bone fractures, and death. Dietary and pharmaceutical treatments for CKD-MBD have diverse effects on serum calcium and phosphorus levels, but their effects on the underlying physiological processes of calcium and phosphorus balance are largely unknown. This study aims to determine the effects of a low versus high phosphorus bioaccessibility diet on whole-body calcium and phosphorus balance and kinetics, including measures such as estimated intestinal absorption. This study will be a randomized two-phase cross-over design trial that will include a controlled study diet, a phosphorus isotope as a tracer for kinetic modeling, stool and urine collections, and blood draws. After screening, eligible participants who choose to enroll in the study will be asked to participate in two cross-over sessions, each of approximately 3 weeks (19 days) duration during which time all food will be provided according to the randomized diet intervention assignment. After the first week on the study diet, participants will be asked to stay at the clinical research center when they will be given oral and intravenous doses of phosphorus isotope. Serial blood draws and complete urine and fecal collections will be made for 5 days, then the final week will only include blood draws. Between cross-over sessions, there will be a washout period of 1-3 weeks. Participants will then switch diets and repeat the same study process as the first session. Calcium and phosphorus whole-body balance, intestinal absorption, renal excretion, and movement to and from bone will be determined for both minerals. This project will provide foundational knowledge of calcium and phosphorus physiology in CKD that will support progress towards preventing morbidity and mortality associated with CKD-MBD.
研究者
入排标准
入选标准
- •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
排除标准
- •) 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
研究组 & 干预措施
CKD patients group 1
assigned to Low P Diet (LP) then High P Diet (HP),
干预措施: LP then HP
CKD patients group 2
assigned to HP, then LP.
干预措施: HP then LP
结局指标
主要结局
Phosphorus Balance
时间窗: 5 days
Determined by analysis of phosphorus content in complete 24-hour urine and stool collections, subtracted from the diet phosphorus content consumed
Calcium Balance
时间窗: 5 days
Determined by analysis of calcium content in complete 24-hour urine and stool collections, subtracted from the diet calcium content consumed
次要结局
- Urine calcium(1 week)
- Fractional phosphorus absorption(12 days)
- Bone phosphorus balance(12 days)
- Bone calcium balance(5 days and 12 days)
- Urine phosphorus(1 week)
- Net phosphorus absorption(1 week)
- Net calcium absorption(1 week)
- Creatinine clearance(2hours, day 8)
- Serum Fibroblast growth factor-23(Day1, Day8)
- Serum Parathyroid hormone(Day1, Day8)
- Serum 1,25-dihydroxyvitamin D(Day1, Day8)
- Serum phosphate(Day1, Day8)
- Serum calcium(Day1, Day8)