Diabetes, kidneys and cholesterol: why this panel also checks eGFR and lipids

It is easy to think of diabetes as a problem with sugar. In practice, the reason diabetes matters is what high sugar does over years to the blood vessels. The two places this shows up most on a blood test are the kidneys and cholesterol. That is why the Diabetes Check includes creatinine, eGFR and a full lipid profile alongside HbA1c, glucose and insulin.

Why diabetes affects the kidneys

Each kidney contains around a million tiny filters, each made of a knot of small blood vessels. Years of high blood sugar and high blood pressure damage these vessels, and the filters slowly lose their ability to clean the blood. Diabetes is one of the leading causes of kidney disease worldwide.

Kidney damage is silent in its early stages. You can lose a large part of your kidney function without feeling any different. By the time symptoms such as swelling or tiredness appear, the damage is usually advanced. A blood test is how it is found early.

What creatinine and eGFR tell you

Creatinine is a waste product from muscle that the kidneys clear from the blood. When the kidneys filter less well, creatinine builds up. On its own, creatinine is affected by how much muscle you have, so labs use it together with your age and sex to calculate eGFR, the estimated glomerular filtration rate. eGFR is an estimate of how much blood your kidneys filter each minute.

LifePrint uses the KDIGO 2024 kidney guideline categories:

• 90 or more: normal filtering.
• 60 to 89: mildly decreased. This is common in healthy adults, especially with age, and is not kidney disease without another sign of damage. LifePrint shows it as a grey zone.
• 45 to 59 and 30 to 44: moderately decreased, in the chronic kidney disease range.
• Below 30: severely decreased. LifePrint treats this as a critical result that needs prompt medical attention.

One low eGFR is not enough to diagnose chronic kidney disease. Dehydration, a heavy workout, a high meat meal or some medicines can lower it for a while. KDIGO asks for a reduced eGFR to be confirmed over at least three months, or for another marker of kidney damage to be present.

Why diabetes and cholesterol go together

Heart attack and stroke are the most common serious complications of type 2 diabetes. High sugar damages the lining of the arteries and makes it easier for cholesterol to build up in the walls. Insulin resistance also changes the blood fats themselves, producing a typical pattern:

• High triglycerides.
• Low HDL cholesterol.
• LDL particles that are smaller and more likely to lodge in artery walls, even when the LDL number looks acceptable.

This pattern often appears years before diabetes itself, so it can be an early clue to insulin resistance. It is also why non-HDL cholesterol is useful. It counts all the cholesterol carried by harmful particles and is less affected by high triglycerides than LDL is.

The targets LifePrint uses

LifePrint uses the SA Heart and Lipid and Atherosclerosis Society of Southern Africa 2018 guideline. For people at low to moderate risk, LDL cholesterol should be below 3.0 mmol/L, triglycerides below 1.7 mmol/L fasting, and HDL cholesterol above 1.0 mmol/L in men and 1.2 mmol/L in women. For non-HDL cholesterol, LifePrint uses below 3.8 mmol/L, following the European ESC/EAS 2019 convention.

People with diabetes are usually placed in a higher risk group, where the guideline sets lower LDL targets, such as below 2.5 or below 1.8 mmol/L. Which target applies depends on your age, how long you have had diabetes, and whether you have kidney disease or other risk factors. That is a judgement for your doctor. LifePrint judges your result against the standard target, and your doctor may set a stricter one for you.

Putting it together

Reading sugar, kidneys and lipids side by side gives a much more complete picture than any one of them alone. A slightly raised HbA1c with healthy lipids and normal kidney function is a different situation from the same HbA1c with high triglycerides and a falling eGFR. The good news is that the same changes that improve blood sugar, including more activity, weight loss where needed and stopping smoking, also help the heart and kidneys.

Your LifePrint report flags each result and tells you how urgently to follow up. If your kidney function or cholesterol is flagged, especially together with a raised sugar, discuss it with a registered healthcare practitioner. This is health information, not a diagnosis.