SA JOURNAL OF DIABETES & VASCULAR DISEASE
EDITORIAL
VOLUME 7 NUMBER 1 • MARCH 2010
3
Screening for chronic kidney disease (CKD) and
practical issues related to diabetic nephropathy
BRIAN RAYNER
S
outh Africa, similar to the rest of the world, is facing
an epidemic of chronic kidney disease (CKD), with
death rates from end-stage renal disease (ESRD) rising
by 67% from 1999 to 2006.
1,2
The major drivers of this
epidemic are type 2 diabetes and/or hypertension in the rest
of the world, but in South Africa, HIV-associated nephropathy
(HIVAN) is an important contributory factor. Increasingly,
HIV infection may occur in the context of both diabetes and
hypertension, and both articles reprinted in this edition of the
South African Journal of Diabetes and Vascular Disease
must
be read in this context.
3,4
Because of the critical shortage of nephrologists in South
Africa, it is essential for endocrinologists and specialist
physicians to be cognisant of the basics of screening,
monitoring and treatment of CKD, as it is not possible for all
patients to be evaluated by a nephrologist.
Screening for CKD in South Africa
The South African Renal Society (SARS) has published
guidelines for the early detection and management of CKD,
which are published on their website.
5
The SARS guidelines
and the article by Lewis are in broad agreement and differ
mostly in the detail. Definitions for CKD and recommendations
for screening are similar, with the major exception related
to HIV, where it is mandatory to screen for CKD in all HIV-
infected persons. Conversely it is also essential that all patients
with CKD undergo HIV testing, even in patients with known
risk factors such as hypertension and diabetes, as these may
co-exist in high-risk populations. The SARS recommendations
for screening at-risk patients are shown in Table 1.
A common misconception is that CKD is defined by
estimated glomerular filtration rate (eGFR) only. It is important
to note that it is not only defined by eGFR
<
60 ml/min over
a three-month period but also by abnormalities in the urine
(proteinuria and/or haematuria) and the structure of the
kidney.
5
An issue which is not clear in the Lewis article and
the SARS guidelines is whether the eGFR in the classification
should be corrected for 1.73 m
2
body surface area.
3,5
The most cost-effective test for screening for CKD is
the urine dipstick and a case can be made for mandatory
screening of all individuals even without risk factors for CKD.
It is inexpensive and simple to perform in consulting rooms,
and most forms of overt renal disease will have urinary dipstick
abnormalities present. If so, then further testing is warranted.
A creatinine (with eGFR) test and a urinary protein/creatinine
ratio are the minimum investigations needed to stage or
determine the severity of the CKD. An ultrasound of the kidney
is also recommended to exclude structural abnormalities and
superimposed obstructive uropathy, especially in older males,
due to prostatic obstruction.
The urinary protein/creatinine ratio is preferred over
the urinary albumin/creatinine ratio as it is less expensive
and easier to perform. However, the latter ratio is more
accurate, particularly for the detection of microalbuminuria
and should be reserved for early detection of diabetic and
probably hypertensive nephropathy. A comparison of
urinary screening tests and their relative usefulness is nicely
summarised by Lewis.
3
From a practical perspective, the
Correspondence to: Brian Rayner
Division of Nephrology and Hypertension, Groote Schuur Hospital and
University of Cape Town, Cape Town
Tel: +27 (0)21 404-3495
e-mail:
S Afr J Diabetes Vasc Dis
2010;
7
: 3–6
Brian Rayner
Table 1.
Risk factors for CKD
Diabetes mellitus
•
Hypertension/cardiovascular disease
•
Age over 50 years
•
Family history of CKD
•
HIV/AIDS
•
