Inclusion criteria: |
Participant is willing and able to give informed consent for participation in the study |
Male or female aged 60 years or above |
Last known estimated glomerular filtration rate (eGFR) <30 ml/min/1.73 m2 by MDRD4 equation |
Serum bicarbonate <22 mmol/L |
Able (in the investigator’s opinion) and willing to comply with all study requirements. |
Exclusion criteria: |
Severe cognitive impairment precluding written informed consent |
Already taking bicarbonate therapy unless a 3-month washout period is planned |
Documented renal tubular acidosis (likely to require bicarbonate, often in very large doses) |
On renal replacement therapy (haemodialysis or peritoneal dialysis) |
Anticipated to start renal replacement therapy within 3 months |
Participant who is terminally ill, as defined as less than 3-months expected survival |
Decompensated chronic heart failure (to ensure that fluid overload is not exacerbated by the additional sodium load from the intervention) |
Bisphosphonate therapy (to avoid obscuring bone turnover effects; patients with eGFR <30 mL/min/1.73 m2 should not usually be taking bisphosphonates as this is a listed contraindication) |
Uncontrolled hypertension at screening visit (BP >150/90 mmHg despite use of four agents), unless evidence from home or 24-hour blood pressure monitoring that blood pressure is usually controlled. |
Subject participated in another clinical trial (other than observational studies and registries) concurrently or within 30 days prior to screening for entry into this study |
Participant has a known allergy to sodium bicarbonate or lactose |