Metabolic Acidosis in CKD: How Bicarbonate Therapy Slows Kidney Decline

What Is Metabolic Acidosis in Chronic Kidney Disease?

Metabolic acidosis happens when your blood becomes too acidic because your kidneys can’t remove enough acid or make enough bicarbonate to balance it. In people with chronic kidney disease (CKD), this isn’t rare-it’s common. By stage 3, about 15% of patients have it. By stage 5, nearly half do. Your kidneys normally filter out acid and keep bicarbonate levels steady. But when kidney function drops below 30%, that system breaks down. The result? Blood bicarbonate falls below 22 mEq/L, and pH dips under 7.35. Left untreated, this doesn’t just cause fatigue or muscle weakness-it speeds up kidney damage, weakens bones, and increases heart risks.

Why Bicarbonate Matters More Than You Think

Bicarbonate isn’t just a number on a lab report. It’s your body’s main buffer against acid. When levels drop, your body starts breaking down muscle to make ammonia, which neutralizes acid. That’s why people with untreated metabolic acidosis lose muscle mass fast-even if they’re eating enough protein. Bones also start dissolving to release calcium carbonate, which fights acid. Over time, this leads to osteoporosis and fractures. Studies show that keeping bicarbonate above 22 mEq/L cuts the risk of kidney function dropping by half. The chronic kidney disease community now treats this like a core part of care, not an afterthought.

The Go-To Treatment: Sodium Bicarbonate

Sodium bicarbonate tablets (650 mg each, giving about 7.6 mEq of bicarbonate) are the most common fix. A major 3-year trial with 740 CKD patients found that taking 0.5-1.0 mEq/kg/day slowed the decline of kidney function by nearly 6 mL/min/1.73m² compared to placebo. That’s the difference between needing dialysis in 8 years versus 5. But there’s a catch: each 500 mg tablet has 610 mg of sodium. For someone with high blood pressure or heart failure, that’s dangerous. Many patients see their blood pressure jump from 130/80 to 160/95 within weeks. That’s why doctors don’t just prescribe it blindly-they check fluid status, heart health, and sodium intake first.

Alternatives to Sodium Bicarbonate

If you can’t tolerate sodium bicarbonate, there are other options. Calcium citrate is one. It gives alkali without the sodium, but each pill adds calcium. Long-term use raises the risk of kidney stones by 27%. Potassium citrate sounds good-no sodium, good for bones-but it’s risky in CKD. About 18% of patients on potassium supplements develop dangerous high potassium levels. In fact, 22% of stage 4 CKD patients on potassium citrate hit potassium above 5.0 mEq/L. That’s a heart rhythm threat. Sodium citrate (Shohl’s solution) is another option, but it’s often too salty or tastes awful. Many patients mix it with orange juice, adding sugar they shouldn’t have.

Diet Can Help-If You Stick With It

Food plays a bigger role than most realize. Meat, cheese, and processed grains are acid factories. A 100g serving of beef adds +9.5 mEq of acid. A slice of cheddar? +8.0 mEq. Fruits and vegetables? They’re acid fighters. Apples, broccoli, spinach-they each subtract 2-3 mEq per 100g. Studies show that shifting 50% of your plate to plant-based foods can slash your daily acid load by 40-60 mEq. One patient in Cleveland Clinic’s CKD clinic raised their bicarbonate by 3.5 mEq/L in six months just by swapping burgers for lentils and chicken for tofu. But it’s hard. Most people don’t know which foods are acidic. A renal dietitian usually needs to walk you through it. And even then, only 35% of patients hit the target of a neutral or negative PRAL score.

The New Kid on the Block: Veverimer and Beyond

Veverimer was supposed to be the game-changer. It’s a pill that traps acid in your gut without being absorbed-so no sodium, no potassium, no calcium. Phase 2 trials showed a 4.3 mEq/L bicarbonate boost in 12 weeks. But the phase 3 trial in 2021 missed its goal. The difference from placebo was just 2.07 mEq/L-not enough to get FDA approval. The company is trying again in 2024 with new data. Meanwhile, a new citrate-free alkali supplement called TRC001 is showing promise in early trials: a 4.1 mEq/L rise in bicarbonate with half the stomach upset of traditional options. It’s not out yet, but it’s one to watch.

Who Gets Treated-and Who Doesn’t

Here’s the uncomfortable truth: only 43% of CKD patients with low bicarbonate get any treatment. And it’s worse for Black patients (38%) and those in rural areas (35%). Many doctors still don’t test bicarbonate regularly. Some think it’s not urgent. But KDIGO guidelines say clearly: if your bicarbonate is below 22 mEq/L, start alkali therapy. The evidence is strong. Yet, in practice, it’s still missed. Partly because there’s no branded drug approved just for this. Everything used is off-label. Partly because patients can’t handle the pill burden. On average, people take 4.2 pills a day. That’s a lot when you’re already taking meds for blood pressure, diabetes, and cholesterol.

How to Monitor Progress

Don’t just start treatment and forget it. Check bicarbonate levels every month when you begin. Once you’re stable, every 3-6 months is fine. Target? 23-29 mEq/L, per KDIGO. But experts are shifting. The 2024 draft guidelines suggest 22-29 mEq/L, recognizing that even 22 mEq/L protects your kidneys. For someone with heart failure, aim for 24-26 mEq/L. For an older, frail patient, 22-24 mEq/L may be safer. It’s not one-size-fits-all. Your doctor should adjust based on your age, heart health, and nutrition. And always track your potassium and calcium levels if you’re on citrate or calcium-based therapies.

What Patients Are Saying

On forums like Reddit and the American Kidney Fund’s community, patients are honest. One person wrote: “I switched from sodium bicarbonate to calcium citrate, but now I have to swallow six pills a day and still get leg cramps.” Another said: “The baking soda powder tastes like chalk. I mix it in orange juice, but I know I shouldn’t be drinking that much sugar.” Adherence is the biggest hurdle. Taste, pill count, side effects like bloating and nausea-all these stop people from sticking with treatment. But those who do? They report feeling less tired, less muscle loss, and fewer hospital visits. One woman said her eGFR held steady for three years after switching to diet + low-dose bicarbonate. She’s still not on dialysis.

The Big Picture: Why This Matters

Correcting metabolic acidosis isn’t about feeling better today. It’s about keeping your kidneys working longer. The National Institute of Diabetes and Digestive and Kidney Diseases estimates that if every eligible CKD patient got proper treatment, we could prevent 28,000 cases of kidney failure each year in the U.S. That’s $1.4 billion in saved healthcare costs. But we won’t get there until doctors start testing bicarbonate routinely, patients get better support for diet changes, and we have safer, easier-to-take medications. Right now, we’re treating a treatable condition like it’s inevitable. It’s not.

What You Can Do Right Now

• Ask your doctor for a serum bicarbonate test if you have CKD stage 3 or higher.
• If your level is below 22 mEq/L, ask about starting alkali therapy-and discuss your options: sodium bicarbonate, calcium citrate, or diet first.
• Get a referral to a renal dietitian. Learn which foods add acid and which fight it.
• Track your blood pressure and swelling if you’re on sodium bicarbonate.
• Don’t take potassium citrate unless your potassium is low and your doctor specifically recommends it.
• Keep your pill count manageable. If you’re taking more than 4 tablets a day, ask if there’s a simpler way.