One in three people over the age of 75 have chronic kidney disease – and I’m one of them. It naturally becomes more common as we age, rising from one in seven cases in adults generally.
My classification as a CKD sufferer depends on a measurement of kidney function called the glomerular filtration rate (GFR), which measures the speed at which your kidneys can filter and clean your blood, described as the number of millilitres a minute. It’s also related to your size and height.
Performing a full GFR test is long and laborious so we’ve come up with an ‘estimated’ GFR. The eGFR is calculated using the levels of certain chemicals in the blood like creatinine.
The higher they are the more slowly your kidneys are cleaning your blood, the lower your eGFR and the greater the risk of needing some kind of replacement therapy.
And this is the nub. The eGFR can be an indication of future deterioration in kidney function over the next five years, so you can plan ahead.
My eGFR hovers around 50 which is the cut-off point of what’s considered normal. So what should an eGFR be? A normal rating is 60 or more. If your eGFR is less than 60 for eight months, your kidneys may not be working well.
As eGFR drops with age, at 50-59 it’s 93, at 60-69 it’s 85 but over 70 years of age, 60 or below could be considered normal, which is how I view mine.
To my mind an estimated figure for a measurement as important as GFR always seemed second best, especially as questions have been raised over the legitimacy of creatinine as a biomarker for renal function.
Therefore, NICE has come up with a more comprehensive calculation to assess renal function – Kidney Failure Risk Equation (KFRE) based on age, gender, eGFR and ARC (augmented renal clearance).
This value can be used as a indicator of future needs as it’s more sensitive and more specific than the eGFR on its own. Patients who are going to need kidney replacement therapy can therefore be identified earlier and receive proper care sooner.
An impressive team of nephrologists headed up by Rouvick M Gama of King’s College Hospital, London, believe the KFRE can provide people with their own risk assessment, and so help them proactively manage their condition and draw up management plans for future care.
You can help keep your eGFR healthy by keeping your blood pressure normal, exercising, limiting alcohol and eating a balanced diet.