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1 July 2009
High prevalence of low HDL cholesterol and hypertriglyceridemia in treated dyslipidemic patients

Only half of dyslipidemic patients reach a normal lipid profile while being on treatment, a French study reports. Persisting lipid abnormalities include LDL cholesterol, HDL cholesterol, and triglycerides levels.

Laforest L, Souchet T, Moulin P, Ritleng C, Desamericq G, Le Jeunne P, Schwalm MS, Van Ganse E.
Summary
Comments & References
STUDY SUMMARY
Methods
To assess the prevalence of low high-density lipoprotein cholesterol (HDL-C) levels and elevated triglycerides (TG) levels in treated dyslipidemic patients, Laforest et al. conducted a cross-sectional study in 2727 French patients (mean age 64.7 years, 46.7% women) who were on lipid-lowering therapy. All patients were followed by GPs affiliated to a national network (Cegedim France). Levels of low-density lipoprotein cholesterol (LDL-C), HDL-C, and TG were compared with target levels recommended by French guidelines. Lipid abnormalities were defined in both genders as fasting triglycerides greater than 150 mg/dL, HDL-C less than 40 mg/dL and LDL-C above the recommended concentration according to French guidelines released in 2005 (Table 1).1
 

Table 1. Target LDL-C level according to French Guidelines

no other risk factor

1 additional risk factor

2 additional risk factors

>2 additional risk factors

CHD history or CHD risk equivalent

<2,20 g/l (5,7 mmol/l)

<1,90 g/l (4,9 mmol/l)

<1,60 g/l (4,1 mmol/l)

<1,30 g/l (3,4 mmol/l)

1 g/l (2,6 mmol/l)

Patients were classified into four groups:

  • group 1: no lipid disorders
  • group 2: low HDL-C and/or high triglycerides concentration with normal LDL-C
  • group 3: isolated elevated LDL-C
group 4: elevated LDL-C and low HDL-C and/or high triglycerides concentration
Main results The prevalence rates of elevated LDL-C, low HDL-C, and elevated TG were 28.0% 10.3%, and 27.2%, respectively. The distribution of lipid disorders is shown in Figure 1.
Among patients meeting target LDL-C, those with high triglycerides and/or low HDL-C exhibited a significantly higher number of cardiovascular risk factors (1.83 vs 1.68, p<0.001).

COMMENT

This study suggests that pharmacological lipid-lowering treatment has finite effects on reaching dyslipidemia therapeutic targets in current practice within primary care. However, the strength of the demonstration is limited by the study design, which did not allow a centralized measurement of lipid parameters. This may have introduced an important bias due to interlaboratory variability in serum lipid measurements. In addition, no information was given about statin dosage and patient’s compliance, two elements that may have impacted the results.

Notwithstanding these reservations, the study shows that only half of treated patients (on statin and fibrate monotherapy in 70% and 24% of cases, respectively) attained recommended lipid targets. This proportion would obviously have been lower if, for example, the NCEP-ATP III guidelines,2 which define a 1.60 mg/dL target for LDL-C concentration in subjects with 0 to 1 additional risk factor had been used instead of French guidelines. The prevalence of elevated LDL-C remained relatively high and more than one third of patients presented with one component of atherogenic dyslipidemia (low HDL-C and elevated TG) or both.

Another finding was that among patients meeting target LDL-C, those with high TG and/or low HDL-C exhibited a significantly higher mean number of cardiovascular risk factors (1.83 vs 1.68, p<0.001). Diabetes and hypertension were independently associated with low HDL-C and/or high TG (p<0.0001 and p=0.03, respectively). This was not unexpected, as low HDL-C and high TG levels are commonly found in patients with the common (type 2) form of diabetes. In addition, glucose homeostasis disturbances, elevated blood pressure, low HDL-C, and elevated TG tend to cluster in people with the metabolic syndrome. As the prevalence of type 2 diabetes and metabolic syndrome has reached epidemic proportions worldwide, clinicians will be increasingly challenged by the complex lipid disorders linked to these two conditions.

Results of this cross-sectional study indicate that much remains to be done to control lipid disorders even in already treated dyslipidemic patients in primary care. To reduce vascular morbidity and mortality in the years to come, more attention should be paid in current practice to attain all recommended targets for the three main atherogenic lipid fractions.
References
  1. . http://www.afssaps.fr/Afssaps-media/Publications/Recommandations-de-bonne-pratique#D_element_name (accessed on 12 May 2009)
  2. Grundy SM et al. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. Circulation 2004;110:227-39.