Blog entry by Meguid El Nahas
In this month Lancet, Zhang et al report a cross-sectional analysis of CKD in China and conclude that 10.8% of the population has CKD; eGFR<60 = 1.7% and Albuminuria (ACR) = 9.4%.
As it is published in the Lancet, I assumed it was a well conducted analysis and became concerned that 119.5 million chinese suffer from CKD!
I was totally wrong on two accounts:
1. Publishing in the Lancet does not garantee quality
2. The study is badly conducted.
1. A cross-sectional survey of a chronic disease is a contradiction in terms; testing 1x does NOT define CKD according to the current KDOQI definition requiring 2 of 3 positive tests over a period of 3 months....the authors and reviewers seem to have overlook this small fact, although it is mentioned in the discussion....!
2. Urine ACR is as much a marker of raised albuminuria than low creatininuria; malnourished rural chinese are likely to suffer from the latter rathen than the former...
3. A number of studies including our own show that repeat albuminuria testing leads to a steady decline in prevalence; the authors should have re-tested! They should also b eaware that microalbuminuria is an acute phase abnormality that regresses with an infection or inflammation subsides! Re-testing is essential!
3. Hypertension is common in China 27-43% and poorly controlled and is a major cause of albuminuria in that study...
4. So what we have is a publication on the high prevalence of hypertension in China with consequent albuminuria if albuminuria exists at all in this sample size... and the answer is:
Perhaps the CKD epidemic in China is easily reversible and curable as one expects albuminuria to regress with control of hypertension.
This article should have been entitled: Uncontroilled hypertension in China as a cause of albuminuria!
This article will be undoubtedly quoted repeatedly byu those on the bandwagon of the "CKD epidemic..."; here in OLA we got off this bandwagon a long time ago when we realised how poor research in this field was. This recent publication reinfoces our conviction!
Zhang et al. Prevalence of chronic kidney disease in China: a cross-sectional analysis. Lancet 2012;379:815-822.