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Irbesartan Versus Amlodipine: The OBI Study (OBI)

This study has been withdrawn prior to enrollment.
(no funding)
Information provided by:
Aristotle University Of Thessaloniki Identifier:
First received: September 30, 2009
Last updated: February 10, 2014
Last verified: September 2009


  1. To study the effectiveness of irbesartan 300mg and amlodipine 10 mg in 24h ambulatory blood pressure values in obese subjects
  2. To study the drug specific effect in arterial stiffness
  3. To study possible drug mechanisms in obesity (reduction of central adiposity and changing the ratio of leptin to adiponectin)

Condition Intervention Phase
Drug: Irbesartan
Drug: Amlodipine
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Diagnostic
Official Title: Double Blind Study of Irbesartan vs. Amlodipine in Obese Hypertensive Subjects- The OBI Study

Resource links provided by NLM:

Further study details as provided by Aristotle University Of Thessaloniki:

Primary Outcome Measures:
  • Reduction of 24h BP and arterial stiffness in obese hypertensives [ Time Frame: 12 ]

Secondary Outcome Measures:
  • New onset of diabetes [ Time Frame: 12 ]
  • Drug specific effect on reduction in central fat deposition and the leptin to adiponectin ratio [ Time Frame: 12 ]

Enrollment: 0
Study Start Date: January 2012
Estimated Study Completion Date: January 2014
Estimated Primary Completion Date: January 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Irbesartan
Treatment with irbesartan 300mg for 4 weeks. IF ABP>135/85 mmHg add HCZ 12.5 mg.
Drug: Irbesartan
Treatment with irbesartan 300mg for 4 weeks. IF ABP>135/85 mmHg add hydrochlorothiazide 12.5 mg.
Active Comparator: Amplodipine
Treatment with amlodipine 10 mg for 4 weeks. If BP>135/85 mmHg add hydrochlorothiazide 12.5 mg
Drug: Amlodipine
Treatment with amlodipine 10 mg for 4 weeks. If ABP>135/85 mmHg add hydrochlorothiazide 12.5 mg

Detailed Description:

Study Objectives

  1. Primary:

    • Reduction of 24h BP in obese hypertensives
    • Reduction in arterial stiffness
  2. Secondary

    • Drug specific effect on new onset of diabetes
    • Drug specific effect on reduction in central fat deposition and the leptin to adiponectin ratio

Study design

Study drugs: Irbesartan 300mg vs. amlodipine 10mg

Tx duration and follow-up: 12 months

Collected data:

  • 24h SBP and DBP in time 0, 1, 12.
  • Pulse wave velocity in time 0,1,12.
  • Central obesity (total, visceral, abdominal fat) in time 0,1,12.
  • Leptin/adiponectin in time 0,1,12.
  • BMI, waist/hip ratio in time 0,1, 12.
  • Glu, HbA1c, insulin in time 0, 1,12.
  • K, Na, Cr, BUN, Chol, Tg, HDL, LDL,ALT, AST in time 0, 1,12. Number of patients: The reduction in mean SBP expected to be 15 mmHg. Previous studies from our group reported an 14mmHg SD for mean SBP. The sample size required at the two sided 5% significance level and 80% power is 40 patients (Lehr's formula)

Number of centers: 1


Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Age between 18 and 60 years.
  2. All patients are going to give their informed consent to participate in the study.
  3. Stage I hypertension.
  4. BMI > 30.

Exclusion Criteria:

  1. Known oversensitiveness,
  2. Chronic renal disease (GFR < 50 ml/min) or ESRD,
  3. Heart or respiratory failure, OR
  4. Recent MI, shock, liver deficiency (ALT or AST > 3 times normal and pregnancy or lactation.
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Please refer to this study by its identifier: NCT00987662

Hypertension-24h ABPM Center Papageorgiou Hospital
Thessaloniki, Greece
Sponsors and Collaborators
Aristotle University Of Thessaloniki
Study Chair: Vasilios Kotsis, Prof AUTH
  More Information

Responsible Party: Kotsis Vasilios/Prof, Papageorgiou hospital hypertension/24h ABPM center Identifier: NCT00987662     History of Changes
Other Study ID Numbers: AUTH170909
Study First Received: September 30, 2009
Last Updated: February 10, 2014

Keywords provided by Aristotle University Of Thessaloniki:
ambulatory blood pressure monitoring
new onset diabetes

Additional relevant MeSH terms:
Antihypertensive Agents
Calcium Channel Blockers
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Vasodilator Agents
Natriuretic Agents
Physiological Effects of Drugs
Sodium Chloride Symporter Inhibitors
Angiotensin II Type 1 Receptor Blockers
Angiotensin Receptor Antagonists processed this record on May 25, 2017