HYT-hypertension in Turkey: a cross-sectional survey on blood pressure control with calcium channel blockers alone or combined with other antihypertensive drugs.

Introduction: Although improved during the past few years, high blood pressure control still remains an unmet goal of antihypertensive drug treatment. Among different antihypertensive agents, calcium channel blockers (CCBs), either as monotherapy or in combination with other drugs are recommended by several guidelines for initiation and maintenance of antihypertensive treatment.
Aim: The HYT-HYperTension survey, carried out in Turkey was aimed to assess (a) blood pressure control in hypertensive patients under treatment with dihydropyridine CCBs, either as monotherapy or in combination with other drugs and (b) the prevalence of blood pressure control in subgroups of patients with cardiovascular risk factors (previous cardiovascular disease, diabetes, renal disease, isolated systolic hypertension, visceral obesity, overweight, current smoking habit).
Methods: More than 7000 hypertensive patients (60.0 % men, mean age 61.2 ± 11.5 years), routinely visited by either a specialist or a non-specialist physician in the Primary Care Units of 26 cities across Turkey, were enrolled in the survey. Only patients treated with dihydropyridine-type CCBs, as mono- or combination therapy were included in the study, whereas individuals treated with non-dihydropyridine-type CCBs or with other drug classes (as monotherapy or combination therapy), were excluded. Demographic data (age, gender, height, weight, waist circumference, current smoker habit), clinical data and drug treatments were collected at each visit. Blood pressure was measured with a semiautomatic device (Omron-M6) with the patient in sitting position and after at least 5 min of rest. Measurements were repeated three times, at intervals of 5 min each other.
Results: In the overall survey population blood pressure control (blood pressure <140/90 mmHg) was achieved in 31.7 % of patients and the average systolic and diastolic blood pressure was 145.3/88.2 mmHg. Prevalence of patients treated with dihydropyridine-type CCBs, either as monotherapy or combined with other drugs, was superimposable (51.6 vs 48.4 %, P = NS). Dihydropyridine-type CCBs were more frequently combined with drugs acting on the renin-angiotensin-aldosterone system (86.4 %), particularly with ACE-inhibitors (34.1 %) and angiotensin II receptor antagonists (52.3 %), while in 13.6 % of patients CCBs were combined with diuretics and/or beta-blockers. Diabetes mellitus was detected in 22.7 % of patients, obesity in 41.5 % and history of cardiovascular disease in 23.0 % (coronary artery disease in 19.2 % and stroke in 3.8 %). Blood pressure control was more difficult to be achieved in complicated hypertension, particularly when cigarette smoking, obesity, overweight, visceral obesity and renal disease were associated with hypertension.
Conclusions: Taken together these findings provide evidence that dihydropyridine-type CCBs, particularly when combined with ACE-inhibitors or angiotensin II receptors blockers, allow to achieve a blood pressure control better than the one reported in the same geographic area by other treatment strategies based on different combinations of diuretics, beta-blockers, ACE-inhibitors, angiotensin II receptors blockers and calcium channel blockers.