Blog entry by Meguid El Nahas
TEXT of the MEDSCAPE VIDEO BLOG by Jeff Berns, MD
Hello. This is Jeffrey Berns, Editor-in-Chief of Medscape Nephrology. The American College of Physicians (ACP) recently released a clinical practice guideline on the screening, monitoring, and treatment of stage 1-3 chronic kidney disease (CKD). Four recommendations were provided, some generating a fair amount of disagreement with the American Society of Nephrology (ASN), the National Kidney Foundation (NKF), and the Renal Physicians Association (RPA). First, the ACP document affirms the asymptomatic nature of stage 1-3 CKD, and that having CKD has health implications, including mortality, cardiovascular disease, fractures, bone loss, cognitive dysfunction, infection, and frailty. They also comment on the common co-occurrence of hypertension, cardiovascular disease, and diabetes. Furthermore, they state that the diagnosis of CKD, regardless of stage, requires laboratory testing.
Before getting to the ACP recommendations, I find it extremely difficult to understand the rationale for lumping together stages 1, 2, 3A, and 3B CKD without specific reference to the prevailing level of albuminuria. This is a rather disparate group of patients to consider under a single guideline, and I'm not sure that I would have set out to lump all of these diverse patient groups together.
Let's look at the ACP recommendations. First there was a weak recommendation based on low-quality evidence against screening for CKD in asymptomatic adults without risk factors for CKD. The text of the article in the Annals of Internal Medicine  cites as risk factors diabetes, hypertension, older age, obesity, and family history of CKD in African American, Native American, and Hispanic patients. That seems to include a huge proportion of the US adult population. Very few people are left potentially unscreened.
Another weak recommendation based on low-quality evidence was that patients who are already on angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB) for hypertension do not need to be tested for proteinuria. It's not specified whether this recommendation applies to patients with known CKD. I cannot imagine that many in the nephrology community don't routinely use some measure of proteinuria or albuminuria to guide ACE inhibitor or ARB treatment of patients with CKD, and I suspect that few, if any, will change their practice on the basis of these guidelines.
Two guidelines address treatment, and both are strong recommendations. One recommendation is to use an ACE inhibitor or an ARB as treatment for hypertension in patients with stage 1-3 CKD, and the other is to use statins to treat high low-density lipoprotein (LDL) levels in these patients. This confuses me a little bit. We should use these treatments in patients with CKD stage 1-3 because they improve patient outcomes, but don't look for patients who might benefit from such therapies? I must be missing something.
An ASN press release urges screening for CKD regardless of risk factors and otherwise pretty much disagrees with the ACP guidelines. The NKF and the RPA are screening for early CKD in patients with risk factors but not in the general population without risk conditions -- again, seemingly a pretty small slice of adults living in this country.
Why look for CKD? You will find poorly controlled hypertension, poorly controlled diabetes, poorly controlled lipid disorders, people who need changes in medications, those who need to avoid certain medications, and people who should be referred for early transplant evaluation. You will find opportunities to educate patients about sodium restriction and weight loss. Our testing tools for estimating glomerular filtration rate (GFR) aren't perfect. They just estimate GFR, but using imperfect tests wisely is probably better than not using them at all.
Finally, let's be clear that screening (which is not really defined in the ACP guideline) is not the same as testing for the presence and severity of CKD in the scope of a patient encounter for general health assessment or management of diabetes, hypertension, and so forth.
Nephrologists shouldn't tell the primary care physicians that they work with to stop looking for CKD. It is still an important health measure, and finding it creates the opportunity to improve patient health.
Thanks for listening. This is Jeff Berns, Editor-in-Chief of Medscape Nephrology, from the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.
Jeff Berns voices the confusion many physicians and nephrologists have faced since the release by the ACP of its clinical practice guidelines relating to CKD screening and management and the subsequent contradictory statements made by representatives of the ASN and NKF.
A number of issues warrant clarification:
1. Are all CKD the same?
CKD has become and all encompassing term covering a very heterogeneous group of people and patients, hence the confusion when physicians are faced with guidelines and recommendations for CKD.
A distinction has to be made between CKD in the community (cCKD) and those seen by physicians and nephrologists who are referred (rCKD) because they suffer from an intrinsic kidney disease such as glomerulonephritis, vasculitis or polycystic kidney disease.
cCKD is mostly a reflection of age-related decline in kidney function, with otherwise healthy older individuals mislabeled as suffering from a disease (CKD), when in reality they merely have a lower GFR commensurate with their age and possibly underlying age-related cardiovascular disease; hypertension and diabetes, mostly type2.
2. To Screen or Not to Screen?
Community screening of asymptomatic individuals for cCKD is not warranted and is not cost effective. Testing for abnormal kidney function in individuals with known disease predisposing to CKD such as hypertension and diabetes is good medical practice. Therefore, in cCKD there is little justification for screening asymptomatic individuals but there is full indication of testing for CKD those with known predisposing conditions such as hypertension and diabetes; both poorly detected, treated and controlled in the US. It is these two conditions that warrant screening for; thus effecting early detection and management.
Screening for rCKD is seldom an issue as these patients often present acutely with a glomerulonephritis, vasculitis, pyelonephritis or other clinical manifestation of intrinsic kidney disease; proteinuria or hematuria. Those with ADPKD often have a family history that justifies the screening.
3. To Treat or Not to Treat?
There’s another legitimate confusion; treat with RAS inhibitors and statins but don't screen? Well, the distinction between cCKD and rCKD should shed some light on such apparent contradiction. Asymptomatic cCKD, older individuals within the community, should be left alone neither screened nor treated, as there is no evidence for benefit from neither; screening or primary prevention.
By contrast, those in the community with cCKD accompanied byas hypertension and/ot diabetes, should be treated appropriately and according to established guidelines that recommend renin-angiotensin system (RAS) inhibition or other drugs to lower blood pressure and reduce the magnitude of overt proteinuria (>1+ by dipstick) inhibition and statin therapy if dys-lipidemia is present. Such treatments should impact favorably on the complications of these conditions including secondary CKD.
Finally, all would agree that rCKD often suffer from hypertension and overt proteinuria justifying treatment with RAS inhibition as recommended by most management guidelines.
I hope that this clarification and distinction between cCKD and rCKD makes some sense of the disparate recommendations and conflicting arguments made by bodies that overlook the heterogeneity of CKD and consequently fail to make coherent recommendations.