Acid-Base Compensation in Chronic Kidney Disease

Duke University14 enrolled

Overview

The purpose of this study is to evaluate changes in urine net acid excretion, blood pressure and body chemistry that occur when the dietary acid load is lowered by using a drug/dietary supplement similar to baking soda. This may be important for patients with kidney disease because they may have difficulty removing all of the dietary acid load from the body in the urine. Participants with and without kidney disease will be recruited. Each participant will be fed a controlled diet for one week with sodium bicarbonate and for one week without sodium bicarbonate to evaluate these changes. The investigators will also determine if the effect of dietary acid load reduction is different in patients with kidney disease compared to those without kidney disease.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Enrollment

Conditions

Chronic Kidney Disease

Interventions

Eligibility

Sex: ALLMin age: 22 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * estimated glomerular filtration rate ≥30 ml/min/1.73m2 * serum bicarbonate 20-28 mEq/L Exclusion Criteria: * diabetes mellitus * uncontrolled hypertension or recent (\<3 weeks) titration of blood pressure medications * clinically significant volume overload on screening physical examination * selected medical conditions other than kidney disease and hypertension (active cancer, chronic liver failure, moderate to severe COPD, New York Heart Association class 2 or greater congestive heart failure, obstructive sleep apnea requiring nightly continuous positive airway pressure, solid organ transplant) * use of alkali supplementation * body mass index \<18.5 or \>40 kg/m2 * ideal body weight \<45.5 kg * anemia at screening (hematocrit \<29% in participants with kidney disease or \<33% in healthy participants) * pregnancy or breastfeeding * allergies, intolerance or unwillingness to consume foods or supplement provided in feeding menu * serum calcium less than 8.6 mg/dl on screening laboratories

Outcomes

Primary Outcomes

Change in ambulatory blood pressure

Change in mean 24 hour systolic and diastolic blood pressure comparing the end of the controlled feeding plus sodium bicarbonate period to the end of the controlled feeding plus table salt period.

Time frame: Measured at the end of each week of intervention (i.e. one week apart)

Change in urine net acid excretion

Change in urine net acid excretion comparing the end of the controlled feeding plus sodium bicarbonate period to the end of the controlled feeding plus table salt period.

Time frame: Urine net acid excretion will be measured at three timepoints over approximately 3 weeks (i.e. 2 weeks of intervention plus one week baseline data collection/run-in)

Secondary Outcomes

Change in clinic blood pressure

Change in average of three readings of systolic and diastolic blood pressure will be evaluated comparing the end of the controlled feeding plus sodium bicarbonate period to the end of the controlled feeding plus table salt period.

Time frame: Clinic blood pressure will be measured at multiple timepoints over approximately 3 weeks (i.e. 2 weeks of intervention plus one week baseline data collection/run-in)

Change in plasma nitric oxide metabolites

Change in nitric oxide metabolites comparing the end of the controlled feeding plus sodium bicarbonate period to the end of the controlled feeding plus table salt period.

Time frame: Measured at the end of each week of intervention (i.e. one week apart) up to 3 weeks