Prevalence of metabolic syndrome in hypertriglyceridaemic patients: higher than it may appear

Dear Editor,

Metabolic syndrome (MetS) is a disorder comprising three or more of the following characteristics: abdominal obesity, high blood pressure, elevated fasting glucose or triglycerides, and low high density lipoprotein cholesterol (HDL-C), that has been included in the International Classification of Diseases, Ninth Revision (code 277.7)1. MetS confers at least a five-fold increased risk for subsequent diabetes, a two-fold risk of cardiovascular disease2, and is associated with a worse outcome in patients with acute myocardial infarction3. The clinical diagnosis of MetS could also be considered relevant because it affects therapeutic strategy in patients at higher risk2.

In a recent study on the predictive factors for achieving therapeutic goals of hypertriglyceridaemia in a large cohort of patients attending the lipid clinics of the Spanish Atherosclerosis Society we observed that patients that did not reach these goals had a higher prevalence of MetS at baseline, and to a greater extent at the end of follow-up, compared with patients that reached these goals4. In this study the diagnosis of MetS was made according to the judgement of each physician. In a subsequent analysis of this cohort of hypertriglyceridaemic patients, we observe that when the diagnosis of MetS was based on the NCEP ATP-III criteria5 or the Joint Interim Statement criteria6, the prevalence of MetS was markedly higher than when it was based on the judgement of each physician (Table 1). Moreover, the prevalence of MetS was higher when the Joint Interim Statement criteria were considered. This may be because of the less stringent threshold value to define abnormal fasting glucose, ≥100 (5.56) vs ≥110 mg/dL (6.11 mmol/l) in the former definition7.

Table 1. Prevalence of metabolic syndrome according to judgement of each physician or to ATP III or to Joint Interim Statement criteria.

	Patients at TG goals (TG < 2.2 mmol/L) n = 406	Patients not at TG goals (TG ≥ 2.2 mmol/L) n = 523	p^a
Judgement of each physician at baseline	180 (48.9%)	312 (61.9%)	<0.001
ATP-III
Baseline visit	272 (67.0%)	393 (75.1%)	0.006
Final visit	143 (35.2%)	364 (69.6%)	<0.001
Joint Interim Statement
Baseline visit	294 (72.4%)	413 (79.0%)	0.020
Final visit	172 (42.4%)	392 (75.0%)	<0.001

^ap by chi squared test.

TG: triglycerides.

In conclusion, nearly three quarters of hypertriglyceridaemic patients in our study fulfil the diagnostic criteria of MetS, but in a high proportion of them this diagnosis may be neglected. Since the diagnosis of MetS has prognostic and therapeutic implications and may also be related with more difficult management of hypertriglyceridaemia, it seems necessary to bridge this clinical gap by paying more attention to the diagnostic criteria of MetS.

Transparency

Declaration of funding

The authors received no payment in preparation of this manuscript.

Declaration of financial/other relationships

There are no conflicts of interest to be declared for any of the authors.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.