Wednesday, 21 May 2008

Proteinuria is confirmed in the QOF

Many people were disappointed that the original chronic kidney disease domain of the Quality and Outcomes Framework, published in early 2006, did not have proteinuria as a key indicator. In particular, the advice that all people with CKD regardless of their level of urinary protein should be treated with ACE inhibitors or angiotensin receptor blockers was at variance with the UK CKD guidelines.

The way the subsection of the QOF domains is arranged - so that each indicator has a number - has also caused a little bit of confusion. The original CKD domain the QOF had four indicators - CKD 1, CKD 2, CKD 3 and CKD 4. They have no relationship to the stages of CKD but, in reality, I think the confusion has been more in secretary care who are less familiar with the QOF than general practitioners and other primary care and community colleagues. The old CKD 4 has now been replaced by CKD 5 : The percentage of patients on the CKD register with hypertension and proteinuria who are treated with an angiotensin converting enzyme inhibitor (ACE) or angiotensin receptor blocker (ARB) (unless a contraindication or side effects are recorded).

But what is proteinuria? Should we be using albumin as the marker for CKD? The draft NICE Guideline on CKD suggested that all people at risk of or with CKD should have a laboratory measured albumin creatinine ratio rather than relay on sticks alone. This has caused a lot of debate and discussion in the kidney community, primary care and laboratory circles. The classic kidney literature is based on proteinuria - often in the old currency of grams of protein per day. Some have questioned how relevant this literature is to the majority of patients we are now picking up with the move to detect asymptomatic kidney disease, often resulting from or linked with vascular injury. Levels of proteinuria are usually considerably less than in those with primary glomerular disease.

Many have also argued that a single standardised measurement in primary care would make sense and albumin creatinine ratios or albumin excretion rates are universally adopted for diabetic kidney disease. However, albumin based assays are more expensive than protein based assays - certainly in terms of re agents. The draft NICE Guidance provides a helpful discussion and an economic analysis.

Where a wide range of opinions are held one often finds the evidence base is lacking and I think this is true when it comes to the proteinuria versus albuminuria debate - so clear need for research, but until the research has been done it will be important to give clear direction and "speak the same language" between primary and secondary care and across the country. The final NICE CKD Guidelines should provide that clarity.