CGM May Work Better Than HbA1c for Kidney Disease

What This Study Found

A 2024 editorial published in the World Journal of Diabetes reviewed how well different tools track blood sugar in people with diabetic kidney disease (DKD). It found that the standard HbA1c test — the one most people with diabetes get every few months — can give inaccurate readings in people with kidney disease. Continuous glucose monitoring (CGM), on the other hand, showed real promise as a more reliable option for this group.

Why HbA1c Falls Short for Kidney Disease Patients

HbA1c measures the average amount of sugar attached to your red blood cells over roughly three months. But in people with kidney disease, two common problems throw off the results:

• Anaemia (low red blood cell count) — Fewer red blood cells means fewer cells to carry sugar, which can make HbA1c look artificially low.
• Kidney dysfunction itself — Damaged kidneys change the lifespan of red blood cells, which distorts the average reading.

This means a doctor could look at an HbA1c result and think blood sugar is under control — when it actually isn't. For someone on dialysis or who has had a kidney transplant, that kind of false reassurance can be genuinely dangerous.

How CGM Helps Fill the Gap

A CGM device uses a small sensor worn on the skin to measure glucose levels throughout the day and night — sometimes every few minutes. Unlike HbA1c, it does not rely on red blood cells at all. This makes it much less affected by anaemia or kidney problems.

The review looked at studies covering three groups of kidney disease patients:

• People on hemodialysis (a machine filters their blood)
• People on peritoneal dialysis (a fluid-based home dialysis method)
• People who have had a kidney transplant

In all three groups, CGM was able to catch dangerous blood sugar swings — both high spikes and low dips — that HbA1c would have missed entirely. People with kidney disease are especially prone to low blood sugar (hypoglycemia), which can cause dizziness, confusion, or even loss of consciousness.

Are There Any Limitations?

The review is honest that CGM is not perfect for kidney disease patients either. Sensor accuracy can fluctuate — particularly during dialysis sessions — and more research is still needed to fine-tune how CGM should be used in clinical practice. Cost and access can also be barriers. Even so, the author concludes that CGM's benefits clearly outweigh its limitations for this population.

What This Means for You

If you have diabetes and kidney disease — especially if you are on dialysis or post-transplant — it is worth asking your doctor whether a CGM device might give a clearer picture of your blood sugar than your HbA1c alone. Catching hidden highs and lows early can help protect both your kidneys and your overall health.

MDS Diabetes stocks a range of CGM devices and diabetes monitoring supplies. If you are considering CGM, visit mdsdiabetes.com to explore your options or speak with your healthcare team about what is right for you.

Citation: Veeranki, Prasad (2024). Utilising continuous glucose monitoring for glycemic control in diabetic kidney disease. World Journal of Diabetes. PMID: 39493559. DOI: 10.4239/wjd.v15.i10.2006