An observational study in Resistant Hypertension and Controlled Hypertension, sponsored by Medical University of Sofia. Completed at 1 site in Bulgaria. Open to participants aged 18 Years to 100 Years. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by Medical University of Sofia · Observational
Study objectives: Our study aimed to assess the prevalence, characteristics, and treatment of patients with resistant hypertension (HTN) in Bulgarian hypertensive population.
Methods: We screened 4340 consecutive cardiovascular patients hospitalized in our clinic and identified 3762 with HTN. Of them, 128 fulfilled the current (2018) European Society of Cardiology and (2023) European Society of Hypertension criteria for resistant HTN and were included in our study. We matched these patients to 128 hospitalized patients with controlled HTN.
We conducted an observational, retrospective, non-interventional study. As a first step, we consecutively screened 4340 patients for HTN. Screening included patients hospitalized at our clinic with various cardiovascular pathologies/diagnoses from 1 July 2018, to 27 March 2024. We identified HTN in 3762 (86.7%) of all patients. In the next step, the hypertensive population was screened for resistant HTN using criteria recommended by the 2018 European Society of Cardiology (ESC)/European Society of Hypertension (ESH) Guidelines and 2023 ESH Guidelines for the management of arterial hypertension. Inclusion criteria for our study were as follows: (1) age ≥ 18 years; (2) an established diagnosis of "Arterial hypertension" according to the 2018 ESC/ESH Guidelines and/or 2023 ESH Guidelines for the diagnosis and treatment of this disease; (3) maintenance of office SBP ≥ 140 mmHg and/or office DBP ≥ 90 mmHg after ≥1 month of treatment with optimal or best-tolerated doses of three or more drugs, including a thiazide/thiazide-like diuretic, an RAAS blocker (either an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin II receptor blocker (ARB)), and a calcium channel blocker (CCB); (4) uncontrolled HTN confirmed by 24-h Holter-BP monitoring; (5) good adherence to the prescribed treatment (≥80% of the treatment period); and (6) patient agreement and signed informed consent at hospital admission to participate in all planned physical, instrumental, and laboratory investigations.
Exclusion criteria for the study were as follows: (1) patients with HTN at target BP values achieved using ≤3 antihypertensive drugs; (2) patients with uncontrolled HTN using ≥3 drugs, but not at optimal doses or not including ACEi/ARB + CCB + thiazide/thiazide-like diuretic or a treatment period of \<1 month; (3) an established diagnosis of "secondary HTN"; (4) suspected/confirmed pseudo-resistant HTN; and (5) patient clinical condition and/or comorbid factors/diseases making the planned instrumental investigations unfeasible. After applying these criteria, we identified 128 patients with resistant HTN, representing 2.9% of all cardiovascular patients (n = 4340) screened and 3.4% of the hypertensive population (n = 3762) in our study. Of the patients with resistant HTN, 63 (49.2%) were male, and 65 (50.8%) were female (p = 0.860). The median age was 58.0 years, with an interquartile range (IQR) of 46.0-69.0 years. In the third step, we used propensity score matching to match 128 hospitalized hypertensives with controlled HTN.
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This study's enrollment of 256 is above the median of 210 across 1,392 observational studies indexed under Hypertension.
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As a first step, we consecutively screened 4340 patients for HTN. Screening included patients hospitalized at our clinic with various cardiovascular pathologies/diagnoses from 1 July 2018, to 27 March 2024. We identified HTN in 3762 (86.7%) of all patients. In the next step, the hypertensive population was screened for resistant HTN using criteria recommended by the 2018 ESC/ESH Guidelines and 2023 ESH Guidelines for the management of arterial hypertension
Inclusion Criteria: (1) age ≥ 18 years; (2) an established diagnosis of "Arterial hypertension" according to the 2018 ESC/ESH Guidelines and/or 2023 ESH Guidelines for the diagnosis and treatment of this disease; (3) maintenance of office SBP ≥ 140 mmHg and/or office DBP ≥ 90 mmHg after ≥1 month of treatment with optimal or best-tolerated doses of three or more drugs, including a thiazide/thiazide-like diuretic, an RAAS blocker (either an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin II receptor blocker (ARB)), and a calcium channel blocker (CCB); (4) uncon- trolled HTN confirmed by 24-h Holter-BP monitoring; (5) good adherence to the prescribed treatment (≥80% of the treatment period); and (6) patient agreement and signed informed consent at hospital admission to participate in all planned physical, instrumental, and laboratory investigations.
Exclusion Criteria:
(1) patients with HTN at target BP values achieved using ≤3 antihypertensive drugs; (2) patients with uncontrolled HTN using
≥3 drugs, but not at optimal doses or not including ACEi/ARB + CCB + thiazide/thiazide-like diuretic or a treatment period of \<1 month; (3) an established diagnosis of "secondary HTN"; (4) suspected/confirmed pseudo-resistant HTN; and (5) patient clinical condition and/or comorbid factors/diseases making the planned instrumental investigations unfeasible.
Patients with 2018 ESC/2023 ESH guidelines criteria for resistant hypertension
Patients with 2018 ESC/2023 ESH guidelines criteria for controlled hypertension
Treatment resistance
Resistance to 3 or more antihypertensive drugs
Time frame: 2018-2024
Plan to share: No — There is currently no plan to share individual participant data with other researchers. Study findings will be disseminated through publications and presentations using aggregate data.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Medical University of Sofia