Bone in CKD Alkali Response (BICARb Pilot Trial)

Inclusion Criteria (Pediatric Inclusion):

• Children 5-17 years old

• Estimated eGFR >30 and <90 ml/min/1.73m2 by CKiD U25 equations

• Females of child-bearing potential must have had a menstrual period in the last month

• Levels of PTH and alkaline phosphatase within 2x normal range and phosphorus within the normal range for age (per local laboratory reference assay)

• 25-hydroxy Vitamin D ≥ 20 ng/mL

• Females of child-bearing potential must be willing to use one form of effective contraception over the course of the study

• Proficiency in English or Spanish

• For participants < 18 years, the participant and/or parent/guardian capable of providing informed consent and assent (assessed by the provider)

Inclusion Criteria (Adult Inclusion):

• Adults ≥ 18 years old

• Estimated eGFR >30 and <90 ml/min/1.73m2 by the new CKD-Epi without race

• Pre-menopausal women of childbearing age must have had a menstrual period in the last month

• Levels of PTH and alkaline phosphatase within 2x normal range and phosphorus up to 5.0 mg/dL (per local laboratory reference assay)

• Levels of 25-hydroxy Vitamin D ≥ 20 ng/mL

• Women of childbearing potential must be willing to use one form of effective contraception over the course of the study

• Proficiency in English or Spanish

Exclusion Criteria (Pediatric and Adult):

• Baseline potassium ≥ 5.5 mEq/L or prior history of hyperkalemia in the last 6 months (potassium > 5.5 mEq/L) or currently taking a potassium lowering agent

• Alkali therapy within the prior 12 months

• Baseline ECG with abnormalities associated with increased risk of arrythmia, excluding left ventricular hypertrophy

• Baseline serum bicarbonate levels < 17 or ≥ 30 mEq/L

• Serum calcium < 8.6 mg/dL, adjusted for serum albumin

• Significant comorbidity causing acid-base imbalance (e.g., active cancer requiring chemotherapy, chronic liver failure, moderate or severe chronic obstructive lung disease, New York Heart Association class 2 or greater congestive heart failure, obstructive sleep apnea requiring nightly continuous positive airway pressure, active glomerular disease requiring immunosuppressive therapy, intestinal malabsorption or celiac disease)

• Plans to relocate out of the area in the next 3 months

• Urine pH > 8 or history of nephrolithiasis

• Lower extremity amputations or non-ambulatory

• Metabolic bone disease not related to CKD (e.g., Paget's disease, primary hyperparathyroidism)

• Endocrinopathy: untreated hyper or hypothyroidism, Cushing's syndrome

• Medical diseases that can affect therapy (severe myocardial damage, acute dehydration, delayed gastric emptying, esophageal compression, or intestinal obstruction or stricture)

• Use of bisphosphonates, denosumab, teriparatide, abaloparatide, romosozumab, raloxifene, estrogen or testosterone replacement therapy, or an unstable dose of glucocorticoids within the 12-months prior to enrollment

• Previous bilateral wrist and tibia fractures

• Solid or liquid organ transplant

• On dialysis or with rapidly deteriorating kidney function or expectation for transplantation or initiation of dialysis in less than 3 months

• Pregnancy or breastfeeding

• Prisoners or institutionalized individuals

• Unwillingness to provide informed consent