Investigations of the Optimum Serum Bicarbonate Level in Renal Disease.

The purpose of this study is to see if treatment with sodium bicarbonate will lower urine levels of proteins that are indicators of kidney damage in people with diabetes who also have chronic kidney disease.

Diabetic chronic kidney disease (CKD) is a common problem in Veterans and progresses to end-stage renal disease in many people. It is important to identify treatment strategies that will help prevent the progression of CKD to overt kidney failure. The purpose of this study is to see if sodium bicarbonate reduces urinary markers of kidney damage in Veterans with diabetic CKD and normal serum bicarbonate levels.

• Chronic Renal Insufficiency
• Diabetes Mellitus

• Drug: Sodium bicarbonate
  Participants will receive 0.5 meq of sodium bicarbonate per 1 kilogram of lean body weight daily. The total amount will be divided into twice daily doses.
• Drug: Placebo
  Participants will receive an identical number of placebo tablets had they been assigned to the intervention. Placebo will be divided into twice daily doses and receive this for six months.

• Active Comparator: Arm 1
  Sodium bicarbonate
  Intervention: Drug: Sodium bicarbonate
• Placebo Comparator: Arm 2
  Placebo
  Intervention: Drug: Placebo

Inclusion Criteria:

1. Veteran
2. Age older than 18 years
3. Type II diabetes mellitus
4. Serum bicarbonate 22 - 28 mmol/L on the most recent measurement within the past six months
5. Stage 2, 3, or 4 CKD (defined as eGFR 15 - 89 ml/min/1.73m2 using the CKD-EPI equation)
6. Urinary albumin:creatinine ratio > 30 mg/gm on the most recent sample within the past 12 months.

Exclusion Criteria:

1. Lean body weight > 100 kg
2. Use of oral medications typically prescribed to raise serum low serum bicarbonate levels (i.e. sodium bicarbonate, sodium citrate, potassium citrate).
3. Serum potassium < 3.5 meq/L at enrollment visit
4. Use of 5 or more antihypertensive agents, regardless of the indications of each agent
5. Systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg at the enrollment or baseline visit
6. Diagnosis of congestive heart failure with current, active Class III or IV New York Heart Association symptoms.
7. Significant fluid overload such that it is unsafe in the opinion of the PI for the patient to participate in the trial
8. chronic gastrointestinal disorder or any other factors judged to be likely to limit adherence to interventions (i.e. alcoholism, a history of missing clinic visits)
9. Chronic immunosuppressive therapy for transplanted organs or other indications
10. Individuals who are currently a member of a vulnerable population (I.e. incarcerated, pregnant).
11. Currently participating in another interventional research study