Chronic kidney disease diagnostic criteria ‘must be reviewed’
Experts have called for a review of criteria for diagnosing chronic kidney disease (CKD), warning that significant numbers of patients – particularly elderly ones – are being labelled with the disease, and potentially treated, unnecessarily.
According to the researchers, current definitions used in international guidelines including those from NICE label as many as one in eight adults and around half of people aged over 70 years as having CKD. Yet low rates of kidney failure suggest many of these will never progress to severe disease.
GPs in the UK have previously expressed concern at labelling elderly patients unnecessarily with CKD. One study from the University of Cardiff found referrals for CKD went up 60% at an NHS Trust after expanded criteria for CKD came in, although a more recent study indicated that elderly patients were being referred appropriately.
Now an editorial in the BMJ, part of a series on the risks and harms of overdiagnosis in a range of conditions, has suggested the definition for stage 3 CKD – an estimated glomerular filtration rate (eGFR) of less than 60 ml/min per 1.73 m2 irrespective of age or sex and whether or not there are signs of kidney damage – should be revised.
The authors noted that currently one in eight adults in the USA meet criteria for stage 3 or higher CKD, yet only one in 3,000 to 5,000 patients are being newly treated for end-stage renal disease. Another study showed less than 1% of patients with stage 3A CKD (45– 59 ml/min per 1.73 m2) in Norway went on to develop end-stage disease.
They concluded that more research is needed to find markers of early renal impairment that identify patients most at risk of severe disease, and call for CKD guidance to be reviewed ‘by a panel with broad representation from specialty and primary care, population health, patient organisations, and civil society with minimal conflicts of interest’.
‘Until better methods are available, we suggest that clinicians consider the age of the patient and the trajectory of eGFR or urinary albumin test results, and acknowledge to patients that at the moment it is uncertain whether mildly reduced renal function in the absence of other risk factors should be treated or not,’ the team recommended.
Professor Roger Gadsby, a GP in Warwickshire and NHS diabetes primary care lead, commented: ‘I completely agree with the conclusions of the article.
‘In my clinical experience I had many older people “labelled” as having CKD stage 3 through having a blood test who in fact had stable renal function with little or no risk of progression to end stage renal failure. They became very anxious and worried when the laboratory result labelled them as having “chronic kidney disease”.
‘In my opinion, we should in the UK follow the Kaiser model and use a formula that takes age into account, so explicitly attempting to avoid labelling low risk elderly people as having the meaningless diagnosis of stage 3 CKD.’