Aims: To evaluate the influence of metabolic syndrome in the effectiveness of antihypertensive treatment and to compare it using the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) (2001 and 2004), International Diabetes Federation (IDF) and American Heart Association/National Heart, Lung and Blood Institute (AHA-NHLBI) definitions.
Methods: The VALSIM (Estudo de Prevalência da Síndrome Metabólica) survey was designed as an observational cross-sectional study performed in a primary healthcare setting in Portugal. The first two adult patients scheduled for an appointment on a given day were invited to participate. The treatment effectiveness was evaluated by the occurrence of uncontrolled hypertension (≥140/90 mmHg) in patients taking antihypertensive drugs. Logistic regression analysis was used to determine the association between uncontrolled hypertension and metabolic risk factors, with adjustments for age, sex, and pattern of antihypertensive treatment.
Results: Among the 16,856 individuals evaluated, 8925-treated hypertensive patients were identified. Only 35.8% of them had controlled hypertension. The risk of poor blood pressure control increased with age, waist circumference, serum levels of triglycerides and HDL-cholesterol. Among treatable risk factors, metabolic syndrome as defined by NCEP-ATP III 2001 diagnostic criteria was the strongest independent predictor of uncontrolled hypertension (odds ratio: 1.23; 95% CI: 1.08-1.41; P=0.002). In opposition, the IDF or AHA-NHLBI definitions of metabolic syndrome failed to identify patients at risk of poor blood pressure control.
Conclusion: Metabolic syndrome is associated with lower effectiveness of antihypertensive therapy and the NCEP-ATP III 2001 definition of metabolic syndrome is the one that better identifies patients at risk of poor blood pressure control.