The Effect of Nebivolol on Insulin Sensitivity

Not Applicable

Completed

Brief Summary: The purpose of this study is to conduct a randomised trial to compare the insulin sensitivity, 24 hour blood pressure profile, and tolerability of nebivolol plus a thiazide-like diuretic versus atenolol plus a thiazide-like diuretic.

Detailed Description: Retrospective studies of treated hypertensive cohorts have strongly implicated beta blocker therapy as increasing the risk of developing new-onset diabetes. This has led to the latest British Hypertension Society guidelines advising caution when using beta blockers particularly in combination with thiazide-like diuretics. However the National Institute of Clinical Excellence recommends beta-blocker + thiazide combinations as the treatment of choice in patients who are not at increased risk of developing diabetes. Nebivolol is a newer class of beta blocker. Some studies in diabetic hypertensive patients have suggested that nebivolol does not impair insulin sensitivity. The aim of this study is to compare the effect on insulin sensitivity of nebivolol versus atenolol, both in combination with a thiazide-like diuretic, in a group of non-diabetic hypertensive patients.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

contraindications to beta-blockade
contraindications to thiazide use
if there was a history of asthma, diabetes, heart failure, bradycardia, atrial fibrillation, AV conduction disturbances
concurrent treatment with verapamil & dilitiazem
childbearing women
compelling indication for treatment with a beta blocker
any condition that will interfere with the treatment or the patient's ability to complete the study

Arm && Interventions

Group	Intervention	Description
nebivolol 2.5mg daily	Nebivolol	nebivolol 2.5mg daily
atenolol 25mg daily	Atenolol	atenolol 25mg daily

Primary Outcome Measures

Name	Time	Method
Insulin Sensitivity Index (ISI)	Baseline, 15, 30, 60, 90, 120m following oral glucose load, at baseline and at the end of each phase(8 weeks treatment	Patients were asked to fast for a minimum of 12 hours prior to each oral glucose tolerance test (OGTT). Venous blood was withdrawn for insulin and glucose analysis, 15 minutes and immediately prior to, and 30, 60, 90 and 120 minutes following an oral glucose load. For each OGTT, the Insulin Sensitivity Index (ISI) was calculated using the standard method for oral glucose tolerance testing. For each OGTT, the Insulin Sensitivity Index (ISI) was calculated using the standard method for oral glucose tolerance testing.

Secondary Outcome Measures

Name	Time	Method
24 Hour Systolic Blood Pressure	Before and after 8 weeks of treatment	The 24-h Ambulatory Blood Pressure Monitoring (ABPM) was recorded at the beginning and end of each beta-blocker treatment period. BP was automatically recorded for 24 h at 30 min intervals. The time periods from 0700h to 2200h and from 2200h to 0700h were defined as daytime and night-time, respectively.
Total Cholesterol	Before and after 8 weeks of treatment	Fasting blood samples were taken at the beginning and end of each treatment period.
HbA1c	Before and after 8 weeks of treatment	Fasting blood samples were taken at the beginning and end of each treatment period.
BMI	Before and after 8 weeks of treatment	Body weights and heights were taken at the beginning and end of each treatment period.