Dietary Acid Reduction and Progression of Chronic Kidney Disease
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 153
- 主要终点
- Difference in the rate of eGFR change during 5 years follow up
研究概览
简要总结
Upon completion, this project will determine if dietary acid reduction done with either fruits and vegetables (F+V) or the medication sodium bicarbonate (NaHCO3) in study participants with high blood pressure (hypertension) and initially normal kidney function but with signs of kidney injury 1) slows progression of chronic kidney disease (CKD); 2) improves indices of cardiovascular risk; and 3) better preserves acid-base status. These studies are designed to determine if the simple and comparatively inexpensive intervention of dietary acid reduction can prevent or reduce adverse outcomes in individuals with early-stage CKD.
详细描述
The long-term objective of this study is to determine if the simple and comparatively inexpensive intervention of dietary acid reduction can prevent or reduce adverse outcomes in individuals with hypertension and early-stage chronic kidney disease (CKD). The specific aims of this study are to determine if dietary acid reduction done with either base-producing fruits and vegetables (F+V) in amounts calculated to reduce participant dietary acid content by half or with sodium bicarbonate (NaHCO3, 0.4 milliequivalents (mEq)/kg body weight (bw), an amount designed to match the alkali content of the prescribed F+V) in participants with initially normal kidney function but with signs of kidney injury 1) slows progression of CKD; 2) improves indices of cardiovascular risk; and 3) better preserves acid-base status. The incidence and prevalence of CKD is increasing along with increased incidence and prevalence of its adverse outcomes, including heart attack and stroke, the latter for which patients with CKD are at increased risk. Most modern diets produce acid when metabolized in the body and some studies suggest that the small amount of acid produced causes progressive and long-term injury to blood vessels in kidneys, heart, and brain, thereby increasing risk for kidney disease and its progression, heart attack and stroke. This study will recruit participants with hypertension and macroalbuminuria (urine albumin [mg]-to-creatinine [g] ratio > 200 mg/g) but with normal estimated glomerular filtration rate (eGFR) greater than or equal to 90 ml/min/1.73 m2) to be randomized to receive dietary acid reduction done with F+V or oral NaHCO3 or to no dietary acid reduction (Usual Care). At study entry and yearly for 5 years, all participants will have 10 milliliters (ml) of blood drawn from an antecubital vein for measurement of pH, partial pressure of carbon dioxide (PCO2), total CO2 (TCO2), creatinine, cystatin-C, low-density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, Lp(a) cholesterol, sodium, potassium, chloride, and citrate. They will also have 20 ml of urine collected for measurement of creatinine, pH, TCO2, ammonium, titratable acidity, albumin, N-acetyl-D-glucosaminidase, angiotensinogen, isoprostane 8-isoprostaglandin F2 alpha (8-iso), and citrate. Body acid will be measured in participants at baseline and at 5 years during an 8-hour protocol conducted in a Texas Tech University Health Sciences Center (TTUHSC) clinic. They will be told to fast after midnight and report to the TTUHSC clinic the following morning at which time they will be given a single oral dose of sodium bicarbonate (NaHCO3, 0.5 mEq/kg) and have 1 ml of blood drawn from a needle maintained in an arm vein for protocol duration for TCO2 before and at 2, 4, and 6 hours after the dose of NaHCO3 was given and urine collected over 8 hours for TCO2, pH, ammonium, and titratable acidity. The change in blood TCO2 in response to the amount of bicarbonate retained the body (dose minus urine bicarbonate excretion) will be used to calculate participant body acid. The course of serum and urine parameters over the 5 years of follow up in those randomized to F+V or NaHCO3 compared to Usual Care will help determine the effect of dietary acid reduction on CKD progression (change in eGFR and in urine indices of kidney injury), indices of cardiovascular disease risk (change in LDL, HDL, and Lp(a) cholesterol, and change in 8-iso), and on participant acid-base status (serum acid-base parameters (pH, PCO2, bicarbonate concentration [HCO3], TCO2, urine citrate excretion, and body acid measurement). These studies will also determine differences in these outcomes with dietary acid reduction done with F+V or NaHCO3.
The investigators hypothesize that dietary acid reduction will 1) reduce kidney injury indicated by lower urine indices of kidney injury and slow kidney function decline indicated by slower eGFR decline rate; 2) improve indices of cardiovascular risk indicated by lower LDL, higher HDL, lower Lp(a) cholesterol, and lower 8-iso; and 3) improve acid-base status indicated by higher serum TCO2, higher urine citrate excretion, and lower body acid. The investigators additionally hypothesize that F+V will have greater benefits on indicators of parameters of cardiovascular risk than NaHCO3. Excretion of urine acid-base parameters will help determine effects of dietary acid reduction on urine acid excretion. Blood pH and PCO2 will be measured using a blood gas analysis system and blood and urine concentrations of albumin and creatinine will be measured with standard techniques. Blood and urine TCO2 will be measured as done previously using fluorimetry techniques in the PI's laboratory. Urine ammonium, titratable acidity, N-Acetyl-beta-D-glucosaminidase, angiotensinogen, isoprostane 8-isoprostaglandin F2 alpha and citrate will be measured as done previously in the laboratory of the Co-PI.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 70 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Non-malignant high blood pressure or hypertension
- •18-70 years old
- •Urine albumin-to-creatine ratio > 200 mg/g creatinine
- •Estimated glomerular filtration rate (eGFR) greater than or equal to 90 ml/min/1.73 m2
- •Serum total CO2 (TCO2) > 22 mmol/l
- •Greater than or equal to 2 primary care visits in the preceding year
- •Able to provide informed consent
排除标准
- •Malignant hypertension or history thereof
- •Primary kidney disease or findings consistent thereof such as > 3 red blood cells per high powered field of urine or urine cellular casts
- •History of diabetes or fasting glucose greater than or equal to 110 mg/dl
- •History of hematologic disorders, malignancies, chronic infections, current pregnancy, history or clinical evidence of cardiovascular disease
- •Peripheral edema or diagnosis associated with edema such as heart/liver failure or nephrotic syndrome
- •Unable to provide consent
研究组 & 干预措施
NaHCO3 (HCO3)
51 participants with hypertension, normal estimated glomerular filtration rate (eGFR) (>90 ml/min/m2) and macroalbuminuria (albumin [mg] to creatinine [g] ratio > 200 mg/g) will receive 0.4 mEq/kg/bw oral tablet dose of sodium bicarbonate (NaHCO3) designed to match the alkali intake of F+V. They will otherwise receive standard care for their medical concerns including angiotensin converting enzyme inhibitor therapy for albuminuria and followed annually for 5 years.
干预措施: NaHCO3 Tablets (Drug)
Fruits and vegetables (F+V)
51 participants with hypertension, normal estimated glomerular filtration rate (eGFR) (>90 ml/min/m2) and macroalbuminuria (albumin [mg] to creatinine [g] ratio > 200 mg/g) will receive a prescribed amount of base-producing fruits and vegetables (F+V) designed to reduce their dietary acid intake by half. Depending on the particular foods used, this amounts to 2-4 cups daily of fruits and vegetables given in weekly allotments. They will otherwise receive standard care for their medical concerns including angiotensin converting enzyme inhibitor therapy for albuminuria and followed annually for 5 years.
干预措施: Fruits and vegetables (F+V) (Other)
Usual Care (UC)
51 participants with hypertension, normal estimated glomerular filtration rate (eGFR) (>90 ml/min/m2) and macroalbuminuria (albumin [mg] to creatinine [g] ratio > 200 mg/g) will receive no additional alkali (neither F+V or NaHCO3) and will receive standard care for their medical concerns, including angiotensin converting enzyme inhibitor therapy for albuminuria and followed annually for 5 years.
干预措施: Usual Care (Other)
结局指标
主要结局
Difference in the rate of eGFR change during 5 years follow up
时间窗: eGFR will be measured at baseline and yearly for 5 years.
The rate of eGFR change (ml/min/1.73 m2/year) will assess CKD progression and will be calculated by dividing the net change in eGFR over 5 years (5-year value minus baseline value) and dividing by 5 years. The investigators hypothesize that dietary acid reduction will lead to a slower rate of eGFR change, indicative of less CKD progression.
Difference in estimated glomerular filtration rate (eGFR) at 5 years follow up
时间窗: eGFR will be measured at baseline and yearly for 5 years.
eGFR (ml/min/1.73 m2) will be calculated using measured serum creatinine and cystatin-C concentrations, age, sex, and whether or not of African American ethnicity using a standard accepted formula. eGFR will be compared among the three groups at 5 years follow up to assess chronic kidney disease (CKD) progression. Higher eGFR is indicative of better-preserved kidney function. The investigators hypothesize that dietary acid reduction will lead to better preserved (higher) eGFR at 5 years.
Difference in the net eGFR change during 5 years follow up
时间窗: eGFR will be measured at baseline and yearly for 5 years.
The net eGFR change (ml/min/1.73 m2) will assess CKD progression and will be calculated by subtracting the 5-year value from the baseline value. The investigators hypothesize that dietary acid reduction will lead to a smaller net eGFR change, indicative of less CKD progression.
Difference in change in urine albumin excretion during 5 years follow up
时间窗: ACR will be measured at baseline and yearly for 5 years.
CKD progression will be assessed by change in the albumin (mg)-to-creatinine (g) ratio (ACR) in a "spot" urine. An increased ACR is indicative of kidney injury and risk for subsequent decrease of kidney function with time. A decrease in ACR is indicative of reduced kidney injury and a lower risk for decreased kidney function with time. The investigators hypothesize that dietary acid reduction will lead to a lower ACR. • ACR will be compared among the three groups as follows: * 5 year value * Net change (5 year value minus baseline value) at five years
Difference in change in urine angiotensinogen (ATG) excretion during 5 years follow up
时间窗: ATG/creatinine will be measured at baseline and yearly for 5 years.
CKD progression will be assessed by change in the ATG (ug)-to-creatinine (g) ratio in a "spot" urine. An increased ATG/creatinine ratio is an indirect measure of kidney levels of angiotensin II and is indicative of increased kidney injury. The investigators hypothesize that dietary acid reduction will lead to a lower ATG/creatinine ratio. • ATG/creatinine will be compared among the three groups as follows: * 5 year value * Net change (5 year value minus baseline value) at five years
Difference in change in urine N-acetyl-D -glucosaminidase (NAG) excretion during 5 years follow up
时间窗: NAG/creatinine will be measured at baseline and yearly for 5 years.
CKD progression will be assessed by change in the NAG (Units)-to-creatinine (g) ratio in a "spot" urine. An increased NAG/creatinine ratio is indicative of increased kidney injury. The investigators hypothesize that dietary acid reduction will lead to a lower NAG/creatinine. • NAG/creatinine will be compared among the three groups as follows: * 5 year value * Net change (5 year value minus baseline value) at five years
次要结局
- Difference in change in serum LDL cholesterol level during 5 years follow up(Serum LDL cholesterol will be measured at baseline and yearly for 5 years.)
- Difference in change in urine Isoprostane 8-isoprostaglandin F2α excretion during 5 years follow up(Urine Isoprostane 8-isoprostaglandin F2α to creatinine ratio will be measured at baseline and yearly for 5 years.)
- Difference in change in serum bicarbonate concentration (HCO3-]) during 5 years follow up(Serum [HCO3-] will be measured at baseline and yearly for 5 years.)
- Difference in change in serum HDL cholesterol level during 5 years follow up(Serum HDL cholesterol will be measured at baseline and yearly for 5 years.)
- Difference in change in serum partial pressure of carbon dioxide gas (PCO2) during 5 years follow up(Serum PCO2 will be measured at baseline and yearly for 5 years.)
- Difference in change in urine citrate excretion during 5 years follow up(Urine citrate excretion will be measured at baseline and yearly for 5 years.)
- Difference in change in serum Lp(a) cholesterol level during 5 years follow up(Serum Lp(a) cholesterol will be measured at baseline and yearly for 5 years.)
- Difference in change in serum total CO2 (TCO2) during 5 years follow up(Serum TCO2 will be measured at baseline and at 5 years.)
- Difference in change in serum pH during 5 years follow up(Serum pH will be measured at baseline and yearly for 5 years.)
- Difference in change in serum citrate concentration during 5 years follow up(Serum citrate will be measured at baseline and yearly for 5 years.)
- Difference in change in body acid retention during 5 years follow up(Acid retention will be measured at baseline and at 5 years.)
研究者
Donald Wesson
Principal Investigator
University of Texas at Austin