presents descriptive statistics for sociodemographic and baseline variables for the 55,518 participants of the DETECT study in 2003. The average systolic BP was 131.7 mmHg and diastolic BP was 79.9 mmHg. Of the participants of the DETECT study, 12.1% had physician diagnosed DM, 29.5% hyperlipidemia, 14.7% CHD and 4.2% previous myocardial infarction. Physician based diagnosis of hypertension (HTNdoc
) was present in 35.5% of all participants (see ). The prevalence rate of physician diagnosed hypertension increased from the youngest age group (18 to 29 years) to the oldest one (75 years and above) from 2.9% from to 62.6%. Physician’s diagnosis or the patient’s self-reported diagnosis of hypertension (HTNdoc,pat
) showed slightly higher prevalence rates: 41.8% in all participants, 6.4% in the youngest age group and 69.5% in the oldest age group. Physician’s or patient’s self-reported diagnosis or a BP measurement with a systolic BP≥140 mmHg and/or a diastolic BP≥90 (HTNdoc,pat,bp
) prevalence rates increased to 55.2% in all participants and were 15.4% and 82.1% in the youngest and oldest age group, respectively. Prevalence rates for hypertension diagnosis according to the National Health and Nutrition Examination Survey (HTNNHANES
) were in a similar range as for HTNdoc,pat,bp
: 56.0% in all participants, 13.3% in the youngest and 86.8% in the oldest age group. Comparing the estimated prevalence rates for HTNdoc
the largest differences measured as ratio of 2 estimated prevalence rates were seen in the youngest age group comparing HTNdoc
. The biggest percent difference in absolute number was present in the oldest age group comparing HTNdoc
. Limitations of the DETECT study exist, because there was only single measurement of blood pressure in a primary care setting done. Some patients have been excluded from the study, because of time restrictions of the physician or no clinical assessment was possible 
. Several measurements are recommended and prevalence of hypertension is dependent from the setting and inclusion criteria of patients 
Sample characteristics of DETECT study participants.
Prevalence rates of hypertension by age, sex and type of diagnosis.
The categories of the measured BP values according to the JNC 7 classification are shown in stratified by age and sex. 14.9% of the participants had normal blood pressure, 44.6% prehypertension, 28.8% stage 1 hypertension and 11.6% stage 2 hypertension. The prevalence rates of hypertension stages 1 and 2 increased together with age. In participants between age 18 and 29 prevalence rates were 10.2% and 1.8%, in patients above 75 years of age prevalence rates were 41.2% and 18.7%, respectively. The mean systolic BP increased continuously with age up to 140.6 mmHg in participants above 75 years of age and diastolic BP increased up to 81.6 mmHg in the age group 60–74 years, but decreased to 79.9 mmHg again in the oldest age group.
Prevalence of JNC 7 Blood Pressure Categories.
Diagnosis, Treatment and Control Rates in the DETECT Study
Across all age groups 61.5% of HTNNHANES cases were diagnosed (coded in the clinical appraisal) by the physicians. In the youngest there was the smallest proportion of diagnosed HTNNHANES cases (17.4% only). In the age group 75+ the fraction of physician diagnosed cases was highest (71.0%). The rates of HTNNHANES cases, which were diagnosed and also treated by physicians increased with higher age: 12.1% in the youngest age group and 65.7% in the oldest age group. Among HTNNHANES cases the proportion of patients with adequate blood pressure control was 21.4% across all groups; it was 5.8% in the youngest and 23.3% in the oldest age group.
Comparison between HYDRA and DETECT Study
The comparison presented in reveals that the proportion of diagnosed patients was lower in the DETECT study in comparison to the HYDRA study. These changes are consistent, and are significant (p<0.05) in all age groups above age 30 for men and women. The comparison between these studies shows also indications of, albeit small, improvements in rates of treated and controlled hypertension. The changes are consistent, although not significant in all gender and age group comparisons. Significant improvements (p<0.05) in the rates of treatment were found in females 30–44 years of age and in males 30–44 and 45–59 years of age. Rates of antihypertensive drug therapy decreased significantly in male patients aged 75 years and older. Adequate BP control was significantly more common in older female patients (age group 60+ years).
Diagnosis, treatment and control rates among NHANES hypertension cases in DETECT and HYDRA study.
Factors Associated with Pharmacotherapy
shows factors associated with pharmacotherapy for hypertension. Patients in the oldest age group were approximately tenfold more likely to take antihypertensive drugs (OR 10.58, 95%-CI 8.36–13.39). Further factors associated with receiving antihypertensive medication in NHANES based cases were female sex (OR 1.18, 95%-CI 1.10–1.27), BMI above 30 kg/m2 (OR 1.72, 95%-CI 1.57–1.89), a history of CHD (OR 4.64, 95%-CI 3.92–5.50), a physician based diagnosis of hyperlipidemia (OR 1.66, 95%-CI 1.54–1.79), DM (OR 1.98, 95%-CI 1.79–2.19) or previous myocardial infarction (OR 2.27, 95%-CI 1.60–3.21). An alternative specification with waist circumference (reference category: not overweight) instead of BMI as a measure of cardiovascular risk gave very similar results. Smoking was negatively associated with receiving antihypertensive medication (OR 0.79, 95%-CI 0.72–0.86).
Determinants of pharmacotherapy among NHANES hypertension cases.
Factors Associated with Blood Pressure Control
In HTNdoc cases, the factors associated with adequate blood pressure control (less than 140/90 mmHg) were female sex (OR 1.16, 95%-CI 1.07–1.25), the presence of CHD (OR 1.25, 95%-CI 1.13–1.39), previous myocardial infarction (OR 1.76, 95%-CI 1.50–2.05) and antihypertensive medication (OR 1.41, 95%-CI 1.23–1.61) (). With increasing age the likelihood of adequate blood pressure control was reduced (OR 0.57, 95%-CI 0.39–0.82 for the highest age group) and also for a BMI above 30 kg/m2 (OR 0.67, 95%-CI 0.61–0.74). An alternative specification with waist circumference (reference category: not overweight) instead of BMI as a measure of cardiovascular risk gave also very similar results in this regression. Comorbidities (hyperlipidemia, DM and lifestyle factors) such as physical activity and smoking status) had no effect on blood pressure control.
Determinants of adequate blood pressure control among physician diagnosed hypertension cases.