An eGFR That Has Been Falling Year on Year
No single report can show this, which is why it is one of the most commonly missed findings on a blood test. Each individual result may have been unremarkable and none of them flagged. The rate of change is the finding, and it carries more information about what happens next than any single value does. That includes whether anything needs doing at all, because a slow drift through later life is expected.
The pattern on your report
- eGFR Low · mild Key
- Creatinine High-normal Key
- Urine ACR High Key
- Hemoglobin Low-normal Supporting
Printed as: Creatinine in umol/Lor mg/dL— Often still inside its range while the eGFR built from it has been falling for years.eGFR in mL/min/1.73m2— Varies between tests in the same person, so two points are not a trend.Hemoglobin in g/Lor g/dL— Drifts down as kidney function falls, because the kidney makes the hormone that drives red cell production.Urine ACR in mg/mmolor mg/g— Two scales differing by roughly ninefold; check which your report uses.
Why the numbers look like this
Filtration declines gradually through adult life in most people as the number of working filtering units falls. That decline is slow, and someone following it will still have adequate function at the end of a normal lifespan.
Progressive kidney disease follows a different slope. Damage to the filters, most often from diabetes or long-standing high blood pressure, causes the remaining units to take on more work. Filtering under higher pressure damages them in turn, so each loss makes the next one more likely and the decline accelerates rather than settling.
Treatment works by interrupting that self-reinforcing loop. Blood pressure control, renin-angiotensin blockade and SGLT2 inhibitors all reduce the pressure across the remaining filters, and that is why they change the slope and not merely the number.
The slope then determines the outcome that matters. Whether someone reaches kidney failure in their lifetime depends far more on how fast they are declining than on where they stand today.
Not being flagged is not the same as normal
Two cautions before reading a slope. The eGFR varies between tests in the same person even with no change in kidney function, so two points are not a trend and a fall between consecutive results may be noise. Illness, dehydration and a new medicine each pull a single value down temporarily, so a dip that recovers is not part of the line. A trend needs several results taken when well, spread across years.
What else on the report can hide this
The urine albumin-to-creatinine ratio is the most useful companion, because protein leak and filtration rate together predict progression far better than either alone. Someone with a modestly reduced eGFR and no protein is in a very different position from someone with the same eGFR and heavy proteinuria.
Blood pressure over time matters as much as the blood results, since it is both a cause and a consequence, and it is the lever with the most evidence behind it.
HbA1c belongs here for the same reason. Diabetes is the leading cause of kidney failure, and the kidney damage begins long before the eGFR moves.
The medication list deserves attention in both directions: which drugs are contributing to the decline, and which protective ones are missing. Regular anti-inflammatories are worth asking about specifically.
There is a genuinely encouraging thing to know here. The slope is not fixed. The treatments above have been shown to flatten it, and the earlier they start the more filtering units there are left to protect. That is exactly what makes spotting the trend worth the effort of pulling up old results.
What usually causes it
Listed from most to least common — not from most to least serious.
- Very common
Age-related decline
A slow drift with no protein in the urine and stable blood pressure. Expected, and not a diagnosis on its own.
- Very common
Diabetes
The leading cause of kidney failure. Protein appears in the urine years before filtration falls, which is why the ACR is checked annually.
- Very common
Long-standing high blood pressure
Both a cause and a consequence, which is what makes the loop self-reinforcing and what makes controlling it so effective.
- Common
Regular anti-inflammatory use
Frequently bought rather than prescribed, and easily missed. Steady long-term use contributes to a decline that looks unexplained.
- Common
Obesity
Increases the workload on each remaining filter. Contributes independently of diabetes and blood pressure.
- Uncommon
Glomerular disease
Blood and protein together in the urine, sometimes with a faster decline. This combination warrants a kidney opinion.
- Uncommon
Obstruction to urine flow
An enlarged prostate is the common version, and it is reversible if found. Ultrasound answers it.
- Uncommon
Polycystic kidney disease
A family history, and a decline beginning earlier in life. Ultrasound identifies it, and treatment is available.
- Rare
Myeloma
A raised calcium, a high total protein or an unexplained anemia alongside a falling eGFR should prompt a paraprotein screen.
What is usually checked next
- Every eGFR result in your record, plotted in order The slope is the finding, and it is invisible on any single report.
- Urine albumin-to-creatinine ratio Combined with the eGFR, it predicts progression far better than either number alone.
- Blood pressure readings over time, and HbA1c The two commonest drivers, and the two with the most treatment evidence behind them.
- A medication review in both directions Finds what is contributing and what protective treatment is missing.
- Kidney ultrasound Identifies obstruction and structural causes, some of which are reversible.
When to seek care sooner
- Emergency Passing little or no urine
- Emergency Breathlessness with swelling of the legs or face
- Same day A sudden steep drop rather than a gradual decline
- Same day Visible blood in the urine
- Soon Bone pain with a raised calcium
- Soon Increasing protein in the urine on successive tests
Questions worth bringing to your appointment
- Can we look at all my eGFR results together rather than just this one?
- How fast is it falling, and is that faster than expected for my age?
- Has my urine been checked for protein?
- Am I on the treatments that slow this down?
- Is there anything I am taking that is making it worse?