Scholze et al. BMC Public Health 2010, 10:529 http://www.biomedcentral.com/1471-2458/10/529 Page 3 of 12 Hypertension Abdominal obesity High triglycerides Low HDL Impaired fasting glucose / type 2 diabetes Hypertension without MetS Hypertension with MetS Hypertension only Hypertension plus 1 MetS criteria Hypertension plus 2 MetS criteria Hypertension plus 3 MetS criteria Hypertension plus 4 MetS criteria Proportion treated Differential drug adherence rate and relative risk of new onset diabetes Prevalence type 2 diabetes Incidence CVD events Direct cost Figure 1 Schematic representation of the burden of illness model. The model considered all patients in Germany, Spain and Italy over the age of 20 years. Two sets of risk groups were defined, totalling seven risk categories. Risk was stratified first into two categories - those patients with hypertension and MetS and those without - where MetS was indicated by the hypertensive individual hav- ing at least two other ATP III criteria, and second into five risk categories - those patients with hypertension only, hypertension plus one other ATP III criteria, hypertension plus two other, hypertension plus three other and hypertension plus four other ATP III criteria (Figure 1). In order to breakdown the hypertension population data into these risk groups we analysed the United States National Health and Nutrition Examina- tion Survey (NHANES) public use database (2000) to assess the conditional structure for the five components of MetS and applied this conditional structure to coun- try-specific prevalence data. Data sources Prevalence data were sourced from a national survey in Germany [31] and published epidemiological studies in Spain [17,32] and Italy [22,33]. In order to estimate the future prevalence up to 2020 compound annual growth rates (CAGRs) were derived from the literature [34] or a multiyear evaluation of the NHANES public use database. Each risk group was divided into those who receive antihypertensive drug treatment and those who don’t. For the treated group the proportion and cost of hyper- tensive subjects treated with each antihypertensive drug class (monotherapy and combination therapy for