This comprehensive review attempts to address whether the syndrome 1) is a useful marker of cardiovascular risk beyond the risk associated with its individual components (central obesity, elevated serum triglycerides, low HDL, elevated blood pressure,, and glucose intolerance), 2) is the result of a well defined pathology explaining the cluster of the risk factors, and 3) should be treated/managed differently than treating the individual risk factors. After an extensive review of the literature, the authors report that 1) the cardiovascular disease risk associated with the “metabolic syndrome” appears to be no greater than the sum of the risks associated with the individual components, 2) at this time, it is uncertain whether insulin resistance or hyperinsulinemia represent the unifying pathophysiology explaining the cluster of the risk factors, and 3) there is no evidence that the treatment of the metabolic syndrome differs from the treatment of the individual risk factors or that the attempt to treat the “core defect” of metabolic syndrome would result in a different outcome than treating the individual risk factors. Finally, the authors questioned the value of diagnosing the syndrome.--Robert J. Chilton, DO
This joint statement from the ADA & EASD addresses a number of concerns regarding the identification of Metabolic Syndrome (MS) using the current NCEP ATPIII or WHO criteria.
The authors appear to forget that ATPIII proposed a definition of MS to identify people who are at risk for CVD at any given LDL cholesterol level. The purpose of identifying these individuals is to reduce the underlying causes in people who do not meet standard criteria for intensive LDL lowering. These criteria include a combination of categorical and borderline risk factors that can be readily measured in clinical practice.
The authors remind us that medical science usually defines a syndrome as an “aggregate of symptoms and signs associated with any morbid process, and constituting together the picture of the disease”. They suggest that the MS requires more study before its designation as a “syndrome” is truly warranted. However, they must keep in mind that someone must propose a definition to allow it to be tested and validated. They do highlight studies with discordant results regarding the predictability of CVD from the ATPIII definition; these studies can be used to further refine the definition rather than refute its existence. The value of having an ICD-9 code is that it supports testing for the multiple components of the MS.
The authors also appear concerned that doctors will neglect diabetes management if they are focused on the MS. They seem to ignore the fact that ATPIII emphasized that DM is a CHD equivalent; the criteria for identifying the MS is meant to be applied for people at risk for DM or CVD not those who have already been identified with either or both. It draws attention to the fact that some CVD risk factors tend to cluster in patients so predisposed. Kittie Wyne, MD, PhD, FACE
Question: There were two major and rather glaring inaccuracies in the ADA/EASD joint statement. The first was their description of type 2 as of being of equal CVD in risk in all such patients. In fact, a small but significant fraction (~10%) of type 2 DM patients who do NOT meet ATP 3 or WHO criteria for MS are clearly NOT as a CVD risk as those who do not. This was published in Diabetes Care. They also incorrectly stated that no particular feature of either criteria for MS has been found to be of particular risk over any other. In fact again, microalbuminuria (WHO criteria) has impressively been shown to be the most predictive of CVD events versus the other criteria. And again, this data has been published in Diabetes Care. I understand the legitimate gripe over standardization of definition. But the almost irrational and palpable disdain thrown up the metabolic syndrome concept in the statement sapped it of any credibility. We needed constructive, not destructive, criticism of MS.
Answer: I agree. Perhaps we could add your comments on to the website to see if other people agree with us.
In this article, the ability of metabolic syndrome to predict diabetes was
intentionally left out of the discussion. I believe this is a grave
omission since the metabolic syndrome appears to be even a greater predictor
for diabetes than for CHD.(Sattar et al,Circulation 2003;108:414-419) In
addition since diabetes is considered a CHD equivalent, a syndrome that
predicts diabetes is not only relevant for diabetes but also for CHD.
Addtionally, it is suggested in the article that the excess risk for CVD in
diabetics was entirely driven by diabetes, and the presence of metabolic
syndrome conferred no additional risk.(Stern et al,Atheroscler Suppl 2005
6:3-6) This argument is refuted by an analysis of NHANES III; in which
those with diabetes but without metabolic syndrome did not appear to have
the CHD risk of a non-diabetic with metabolic syndrome. Also, in the same
NHANES analysis, those with both diabetes and metabolic syndrome conferred
the highest CHD risk profile.(Alexander et al, Diabetes Care
There are many relevant issues discussed in this article; but perhaps the
most relevant is the concept of a metabolic disorder that portends an
adverse outcome, and is growing at an alarming rate in this country. One
might think that the enormity of the public health impact relative to the
apparent predictive cardiovascular risk should be enough to ensure metabolic
syndrome a place as a diagnostic entity. Until more data are available,
the current definition of the metabolic syndrome has added a valuable tool
to the clinical practice of the everyday practitioner. It would be a great
disservice to patients and clinicians alike to remove this tool from their
diagnostic and therapeutic armamentarium. We need to remember that the
concept of a metabolic syndrome is still in its infancy and we should not
throw this baby out with the bath water. --Michael Clearfield, DO, FACOI
This is a provocative article. It would be best if metabolic syndrome referred onto to those with a glucose of 100-125 + 2 additional risk factors. We know diabetics are at very high risk. We need to treat all the individual risk factors. We may want to aim for secondary prevention targets in those met syndrome patients with advanced subclinical atherosclerosis.
We all also need to help people prevent risk factor development in the first place. As Lew Kuller of Pittsburgh once said at an NCEP meeting, the metabolic syndrome refers to pudgy folks who need to walk more and eat less.
-Roger Blumenthal, MD