AC/DC Study: Acidification Test in Patients With Chronic Kidney Disease and Healthy Controls

Patients with CKD:

• Male or female adults (≥18 years)
• Chronic kidney disease stage 4 (eGFR: 15-30 ml/min/1.73 m2, calculated using the CKD-EPI equation)

Healthy controls:

• Healthy male or female adults (≥ 18 years)
• Normal kidney function (eGFR > 90 ml/min/1.73 m2, calculated using the CKD-EPI equation)

Exclusion Criteria:

• CKD patients
• Plasma bicarbonate level \< 20.0 mmol/l
• Serum potassium >5.5 mmol/l
• Sodium bicarbonate use in the month preceding the test
• Heart failure (NYHA III or IV)
• Liver cirrhosis (Child Pugh B or C)
• Blood pressure >140/90 mmHg despite the use of 3 different anti-hypertensive drugs
• Kidney transplantation
• Use of calcineurin inhibitors (these immunosuppressive drugs affect acid-base balance)
• Known urea cycle disorder
• Alcoholism or drug use
• Pregnancy
• Current use of antibiotics, NSAIDS or alkalizing drugs (sodium-bicarbonate, citric acid, potassium citrate, acetazolamide)
• Inability to adhere to the study protocol (due to language barrier or intellectual disability)

Healthy controls:

• eGFR \< 90 ml/min/1.73 m2 (calculated using the CKD-EPI equation)
• Plasma bicarbonate \< 20 mmol/l
• History of, or drugs for, diabetes mellitus
• History of chronic diarrheal disease
• Ileostomy/colostomy
• Known urea cycle disorder
• Alcoholism or drug use
• Pregnancy
• Current use of antibiotics, antihypertensive drugs, NSAIDS or alkalizing drugs (sodium-bicarbonate, citric acid, potassium citrate, acetazolamide)
• Inability to adhere to the study protocol (due to language barrier or intellectual disability)