"The metabolic syndrome... is dead": these reports are an exaggeration.
The debates continue over the validity of the metabolic syndrome concept. The continuous increment of the obesity pandemic is almost worldwide paralleled by rising rates of metabolic syndrome prevalence. Then, it seems obvious that these debates drove the need for further investigations as well as a deeper cooperation between relevant national and international organizations regarding the issue. Instead, part of the scientific community elected to totally "dismiss" the concept of the metabolic syndrome. Meanwhile, the best available evidence from three consecutive large meta-analyses has systematically shown that people with metabolic syndrome are at increased risk of cardiovascular events. The most recent and largest of them included near one million patients (total n = 951,083). The investigators concluded that the metabolic syndrome is associated with a 2-fold increase in cardiovascular outcomes and a 1.5-fold increase in all-cause mortality rates. One of the ways to hit the metabolic syndrome is an utterly simplistic view on this concept as a predictive tool only. Of course, the presence of the metabolic syndrome possesses a definite predictive value, but first of all it is a widely accepted concept regarding a biological condition based on the complex and interrelated pathophysiological mechanisms starting from excess central adiposity and insulin resistance. Therefore, it is completely unfair to compare it with statistically constructed predictive tools, including stronger prognostic variables even unrelated to each other from the biological point of view. For example, in the criteria for metabolic syndrome (in contrast to Framingham score) age and cholesterol--presumably low density lipoprotein-cholesterol (LDL-C)--levels are not included, as well as a variety of strong predictors used in other risk-stratification scores: previous myocardial infarction, heart failure, smoking, family history, etc. However, the metabolic syndrome identifies additional important residual vascular risk mainly associated with insulin resistance and atherogenic dyslipidemia (low high density lipoprotein-cholesterol (HDL-C), high triglycerides, small, dense LDL-C). Therefore, the metabolic syndrome could be a useful additional contributor in estimation of global cardiovascular risk beyond age, high LDL-C or other standard risk factors. The components of the metabolic syndrome have partially overlapping mechanisms of pathogenic actions mediated through common metabolic pathways. Therefore their total combined effect could be less than the summed of the individual effects. The concept that the metabolic syndrome is a consequence of obesity and insulin resistance, provides a useful "life-style changes" approach for prevention and treatment: caloric restriction, weight-loss and increased physical activity. The next step could theoretically be pharmacological interventions such as metformin, acarbose, fibrates, weight-loss drugs (currently only orlistat is practically available) and perhaps glucagon-like peptide-1 agonists. A third step should probably be kept for bariatric surgery.
Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel. altenen@yahoo.com
Alexander
A
Tenenbaum
Enrique Z
EZ
Fisman
D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000517:prevention & control; D019317:Evidence-Based Medicine; D006801:Humans; D024821:Metabolic Syndrome / Q000145:classification / Q000453:epidemiology* / Q000628:therapy; D009765:Obesity / Q000453:epidemiology* / Q000628:therapy; D018570:Risk Assessment; D012307:Risk Factors; D009626:Terminology as Topic
J Am Coll Cardiol. 2007 Jan 30;49(4):403-14
17258085
Mt Sinai J Med. 2010 Sep-Oct;77(5):524-32
20960554
Cardiovasc Diabetol. 2009 Jul 20;8:37
19619292
Hum Biol. 2007 Apr;79(2):191-200
18027814
Cardiovasc Diabetol. 2009 Sep 15;8:51
19754934
Curr Diab Rep. 2011 Apr;11(2):91-8
21207204
Am Heart J. 2007 Apr;153(4):559-65
17383294
Int J Cardiol. 2004 Nov;97(2):167-72
15458679
Hypertens Res. 2008 Feb;31(2):235-41
18360042
Lancet. 2010 Jan 16;375(9710):181-3
20109902
Circ J. 2009 Aug;73(8):1454-8
19531901
Arterioscler Thromb Vasc Biol. 2007 Mar;27(3):635-41
17194889
Diabetes Care. 2009 Mar;32(3):493-8
18984774
Circulation. 2004 May 11;109(18):2197-202
15123532
Eur Heart J. 2005 Oct;26(19):2032-8
15872029
Cardiovasc Diabetol. 2011 Jan 20;10:7
21251281
Arch Intern Med. 2006 Apr 10;166(7):737-41
16606809
Lancet. 2008 Jun 7;371(9628):1927-35
18501419
Arch Intern Med. 2006 Apr 10;166(7):743-8
16606810
Endocr Rev. 2008 Dec;29(7):777-822
18971485
Diabetologia. 2005 Sep;48(9):1684-99
16079964
J Am Coll Cardiol. 2010 Sep 28;56(14):1113-32
20863953
Curr Opin Lipidol. 2009 Apr;20(2):127-34
19276891
Diabetologia. 2006 Jan;49(1):49-55
16341841
Circulation. 2009 Oct 20;120(16):1640-5
19805654
Med J Aust. 2007 Apr 16;186(8):400-3
17437393
BMJ. 2006 Apr 15;332(7546):878-82
16510492
Am J Med. 2006 Oct;119(10):812-9
17000207
Cardiovasc Diabetol. 2010 Jun 15;9:24
20550659
Heart. 2004 Dec;90(12):1379-83
15547007
Curr Hypertens Rep. 2008 Feb;10(1):32-8
18367024
Diabetes. 2001 Feb;50 Suppl 1:S160-3
11272181
Annu Rev Med. 1993;44:121-31
8476236
Am J Med. 2004 Mar 8;116 Suppl 5A:11S-22S
15019859
J Nutr. 2009 May;139(5):842-8
19321583
Cardiovasc Diabetol. 2010 Mar 23;9:11
20331890
Am J Cardiol. 2007 Mar 1;99(5):667-72
17317369
Curr Diabetes Rev. 2006 Nov;2(4):397-407
18220644
Cardiovasc Diabetol. 2002 Sep 27;1:3
12392600
Exp Clin Endocrinol Diabetes. 2010 Nov;118(10):685-91
20625974
Curr Hypertens Rep. 2010 Apr;12(2):113-9
20424936
Circulation. 2004 Sep 7;110(10):1251-7
15326061
Gend Med. 2007;4 Suppl B:S162-77
18156101
Atherosclerosis. 2007 Sep;194(1):265-71
16970952
Cardiovasc Diabetol. 2010 Aug 09;9:34
20696055
Lancet. 2008 Jun 7;371(9628):1892-3
18501420
Cardiovasc Diabetol. 2010 Oct 11;9:62
20937099
Cardiovasc Diabetol. 2003 Mar 23;2:4
12834541
Hypertension. 2000 Jan;35(1 Pt 2):507-11
10642350
Cardiovasc Diabetol. 2010 Dec 09;9:87
21143879
Curr Opin Clin Nutr Metab Care. 2010 Jul;13(4):391-6
20473151
Cardiovasc Diabetol. 2010 Jul 15;9:30
20633271
Arch Intern Med. 2005 May 23;165(10):1154-60
15911729