CKD, Electrolyte and Fluid Balance Conditions, Metabolic Acidosis
Conditions
Brief summary
With this research the investigators want to study how patients with chronic kidney disease respond to different sodium- and potassium salts. Potassium salts can prevent kidney damage and cardiovascular disease, however patients with chronic kidney disease can responds differently. Extra potassium can increase the amount of potassium in the blood and extra chloride can cause acidosis. With this study the investigators will gain more insight in how patients with chronic kidney disease respond to sodium and potassium salts and which one is more favorable.This information can then be used to guide the application of salt substitutes and dietary adjustments in patients with chronic kidney disease.
Detailed description
Rationale: Patients with chronic kidney disease (CKD) consume a low potassium diet which is associated with progressive CKD and cardiovascular disease. Increasing dietary potassium intake to recommended levels may therefore improve cardiorenal outcomes, but the response to increased potassium intake in patients with CKD is unclear. Therefore, the investigators recently tested the response to 40 mmol potassium chloride in patients with CKD and showed that this is generally well-tolerated. However, patients did develop mild hyperchloremic metabolic acidosis, which may offset the beneficial effects of potassium. The investigators hypothesize that this is a form of chloride-induced acidosis that may be prevented by giving potassium with a different anion than chloride. To further investigate this, the investigators propose to test the response to five different sodium and potassium salts in patients with CKD. These results should inform us on how to best correct a potassium-deficient diet in patients with CKD. Objective: To test the effects of five different sodium and potassium salts in patients with CKD. Study design: Investigator-initiated, single-center, placebo-controlled double-blind randomized crossover study. Study population: Adult outpatients (age ≥ 18 years) with CKD stage G3b or G4 using renin-angiotensin-aldosterone system inhibitors (RAAS-I). Intervention: Capsules with 40 mmol potassium chloride, potassium bicarbonate, potassium gluconate, sodium bicarbonate, sodium chloride or placebo (3 x 3 capsules per day). Main study parameters/endpoints: Difference in plasma bicarbonate after treatment. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The study lasts 6 weeks and consists of 7 visits that will consist of blood sampling, 24-hour urine collection and spot urine collection. We will also provide an automated blood pressure measuring device for at home blood pressure measurements. Although these procedures are time-consuming and may be experienced as burdensome, they are all routine clinical measurements and safe. Patients may experience a pill-burden. The two risks of the salt supplements are hyperkalemia (with potassium salts) and hypertension (with sodium salts). Based on our previous studies a minority of patients is expected to develop these side-effects (\< 12%). Safety measures to prevent, monitor and treat these side-effects are included in the study protocol. There are no direct benefits for patients participating in this trial, but the results will contribute to a better understanding on the feasibility of dietary modifications and salt substitution in patients with CKD to improve health. Patients will be reimbursed for their participation.
Interventions
DIETARY_SUPPLEMENTDietary supplement consisting of 40 mmol/daily of potassium chloride
The supplements are delivered in plain vegetable 00 caps, stabelizing additives are potatostarch, sunflower lecithine and sunflower oil. The capsuels are free of titanium oxide and suited for human consumption.
DIETARY_SUPPLEMENTDietary supplement consisting of 40 mmol/daily of potassium gluconate
The supplements are delivered in plain vegetable 00 caps, stabelizing additives are potatostarch, sunflower lecithine and sunflower oil. The capsuels are free of titanium oxide and suited for human consumption.
DIETARY_SUPPLEMENTDietary supplement consisting of 40 mmol/daily of potassium bicarbonate
The supplements are delivered in plain vegetable 00 caps, stabelizing additives are potatostarch, sunflower lecithine and sunflower oil. The capsuels are free of titanium oxide and suited for human consumption.
DIETARY_SUPPLEMENTDietary supplement consisting of 40 mmol/daily of sodium chloride
The supplements are delivered in plain vegetable 00 caps, stabelizing additives are potatostarch, sunflower lecithine and sunflower oil. The capsuels are free of titanium oxide and suited for human consumption.
DIETARY_SUPPLEMENTDietary supplement consisting of 40 mmol/daily of sodium bicarbonate
The supplements are delivered in plain vegetable 00 caps, stabelizing additives are potatostarch, sunflower lecithine and sunflower oil. The capsuels are free of titanium oxide and suited for human consumption.
DIETARY_SUPPLEMENTPlacebo caps
The supplements are delivered in plain vegetable 00 caps, stabelizing additives are potatostarch, sunflower lecithine and sunflower oil. The capsuels are free of titanium oxide and suited for human consumption.
Sponsors
Erasmus Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Investigator)
Intervention model description
Single-center, placebo-controlled double-blind randomized crossover study.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Adult patients (≥ 18 years) * CKD G3b or G4 (44 - 15 ml/min/1.73 m2) * Use of RAAS-I (ACE-inhibitor or angiotensin receptor blocker, ARB)
Exclusion criteria
* Use of any of the following drugs or supplements: mineralocorticoid receptor antagonists, potassium-sparing diuretics, oral potassium binders, immunosuppressive medication, tolvaptan, acetazolamide, topiramate, sodium bicarbonate. * Patients using double RAAS blockade (i.e., ACE-inhibitor + ARB). * Metabolic alkalosis (plasma bicarbonate \>27 mmol/L) at last outpatient visit * Kidney transplant recipients * Patients with an active gastro-intestinal ulcer * Patients with previous history of ventricular cardiac arrhythmia * Patients with a life expectancy \< 6 months * Incapacitated subjects or subjects who are deemed unfit to adequately adhere to instructions from the research team * Women who are pregnant, breastfeeding or consider pregnancy in the coming 7 weeks * Patients with chronic respiratory acidosis in previous medical history * Hyperkalemia (plasma potassium \>5.5 mmol/L) at V0
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Plasma bicarbonate by blood draw | After 5 days of intervention | The absolute difference per treatment group in measured plasma bicarbonate after treatment. After each treatment of 5 days, plasma bicarbonate will be measured by blood sampling. The difference between the groups (treatments) will be the main outcome and comparator. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Urinary citrate | After 5 days of intervention | Urinary citrate in mmol/24h |
| Urinary ammonia | After 5 days of intervention | urinary ammonia in mmol/24, calculated using the Berthelot method |
| Titratable acid | After 5 days of intervention | Titratable acid = (0.067) × (mLs NaOH (sample titration) - mLs NaOH (blank titration)) × 75/ mLs of sample |
| Plasma electrolyte levels | After 5 days of intervention | Na, Cl, K, Mg, Ca, Phosphate (all in mmol/L) |
| Potential renal acid load | After 5 days of intervention | PRAL (mEq/d) = 0.49 × protein (g/d) + 0.037 × phosphate (mg/d) - 0.021 × potassium (mg/d) - 0.026 × magnesium (mg/d) - 0.013 × calcium (mg/d). |
| Body weight | After 5 days of intervention | Weight measured by a scale in kilograms |
| Blood pressure | 2 measurements in the morning and evening for 5 days per treatment repeated for 6 treatments in total | Systolic and diastolic blood pressure measured 2 times daily during the study, so 20 times during the 5 days of supplement usage. Measurements will be done in the morning and evening measured twice in seated position with an automatic blood pressure monitor. |
| Net acid excretion | After 5 days of intervention | Net acid excretion unit/24h, formula = sum of the titratable acid and concentration of ammonia minus the concentration of bicarbonate. |
Countries
Netherlands
Outcome results
None listed