eGFR not accurate enough for QOF
GPs may mistakenly identify large numbers of patients with chronic kidney disease using the diagnostic algorithm in the quality and outcomes framework.
A new study reveals that using the MDRD formula for estimating glomerular filtration rate becomes progressively less accurate with milder forms of CKD. Below the cut-off of 60ml/min/1.73m2 for stage 3 CKD, the algorithm identifies only 79 per cent of patients with the correct stage of illness.
In milder disease, accuracy is even worse with only 59 per cent of patients correctly staged in the 60-90 range.
The research, to be presented at the British Renal Society and Renal Association conference in Harrogate in May, raises doubts over the wisdom of including eGFR in the QOF.
Study leader Dr Pei Kao, specialist registrar in nephrology at Ninewells Hospital, Dundee, told Pulse: 'It has a negative bias some of the results you get as less than 60 could be an underestimation, they could be 80.'
A second study to be presented to the conference warned the MDRD algorithm 'may need to be modified before being used for targeted screening' after using it in nearly 700 patients.
Study leader Dr Colin Geddes, consultant nephrologist at the Western Infirmary, Glasgow, said: 'It was developed in patients with renal failure it doesn't perform well in patients with normal renal function.'
Professor Mike Kirby, professor in health and human sciences at the University of Hertfordshire and a GP in Letch- worth, said: 'People need to remember it's only an estimate.'