February 2007: Tackling the QOF2 indicators for CKD
Symposium: Renal medicine
Symposium: Renal medicine
How is eGFR determined?
In some parts of the UK, GPs still do not have access to laboratory-issued eGFR measurements, and currently calculate eGFR using online calculators.
There are different ways to calculate or measure GFR, but from April 2006 all UK laboratories have been instructed to report eGFR values derived from the four-variable MDRD formula (see box 2, attached).
When is eGFR unreliable?
There are several confounding factors that can affect the accuracy and validity of eGFR. It should only be used in situations where renal function is stable, or not changing quickly. It should not be used in patients under 18 years. It is not validated in pregnant women, the terminally ill or patients requiring intensive care. It may be inaccurate in patients with unusual body types, such as bodybuilders, amputees and the morbidly obese.
It is not known if or how eGFR should be adjusted for race, except for Afro-Caribbeans. It is least accurate in the range of 60-90ml/min (CKD stages one and two). Drug dosing should be performed using Cockcroft-Gault creatinine clearance.
Which patients should be on the register?
The QOF guidance states that staging can only be applied if eGFR is maintained at less than 60ml/min/1.73m2 for three months.
Patients should then be classed as having CKD stage three, four or five as appropriate. At least one clinical system supplier provides a software tool to facilitate this.
Although not all CKD stage four patients will progress to stage five, such patients should be carefully considered and normally are discussed with, and referred to, a nephrologist. Patients in CKD stage three need to be codified once it is established that they are consistently at this level (more than three months). The initial stratification using eGFR then needs to be refined by context and risk factors (for example, a diabetes patient with significant proteinuria is a CKD stage three patient at great cardiac and renal risk). Many older, well patients fall into this category; possibly 25 per cent or more of the population >80 years. These patients should also be stratified for cardiac and renal risk – those with low or normal BP and little or no proteinuria do not need more than monitoring and exclusion of anaemia.
A high proportion of patients identified as having CKD will already be on the diabetes and/or CHD registers, and will be in a recall system.
When should exception codes be used?
Many patients on the register will already be seen by secondary care. It can be argued that these patients can be excepted from the CKD4 indicator as ‘not clinically indicated', if specialists do not feel that treatment with an ACEI or ARB is appropriate. It is worth seeking the approval of the PCT assessor if it is planned to except more than a few patients, and it is good practice to record the reason for any exception code in the patient's notes.
Which patients should GPs follow up?
Patients with stages four and five CKD could justifiably be referred to secondary care, whereas patients in stage three can be followed up in primary care.
It is very useful to open a dialogue with renal consultant colleagues. Many renal units are developing referral guidance to streamline patient assessment and management.
Strictly, BP monitoring is only required once every 15 months. However, most GPs would probably wish to see patients more frequently than once a year, especially if BP control was difficult.
Renal function should probably be monitored every six months. Patients could be recalled to see the practice nurse every six months for BP and U&E measurements, with a protocol in place to direct patients to see the doctor if BP is above target.Table 1: QOF2 CKD indicators Box 2: The four variable MDRD formula to calculate GFR Authors
Dr Nigel Kendall
Dr David Goldsmith
consultant nephrologist, Guy's Hospital