Trial Outcomes & Findings for Genetic Determinants of Response to Beta Blockade (NCT NCT00837902)

Last Updated: 2018-11-30

Results Overview

Reduction in heart rate based upon genotype while exercising. Participants exercised on a recumbent bike for 2 minutes at 25W, 2 minutes at 50W, and 2 minutes at 75W twice, once before taking atenolol, and once 2.5 hours after oral administration of 25 mg of atenolol. Data points represent unadjusted mean reduction in heart rate in the 3 genotype groups.

Recruitment status

COMPLETED

Study phase

Target enrollment

154 participants

Primary outcome timeframe

2 exercise periods of 6 minutes each. 6 minutes of exercise before taking atenolol, and 6 minutes of exercise starting 2.5 hours after taking 25 mg of atenolol (2.5 hours + 6 minutes)

Results posted on

2018-11-30

Participant Flow

Participant milestones

Participant milestones
Measure	White Participants--Atenolol Unrelated white American subjects	Black Participants-Atenolol Unrelated black American subjects
Overall Study STARTED	85	69
Overall Study COMPLETED	85	69
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Genetic Determinants of Response to Beta Blockade

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	White Participants--Atenolol n=85 Participants Unrelated black and white American subjects were eligible to participate if they were between 18 and 50 years old and had no clinically significant abnormality based on medical history, physical exam, electrocardiogram and routine laboratory testing. Subjects were free of medications for at least 1 week. They also received an alcohol and caffeine free diet for 6 days prior to the study.	Black Participants-Atenolol n=69 Participants Unrelated black and white American subjects were eligible to participate if they were between 18 and 50 years old and had no clinically significant abnormality based on medical history, physical exam, electrocardiogram and routine laboratory testing. Subjects were free of medications for at least 1 week. They also received an alcohol and caffeine free diet for 6 days prior to the study	Total n=154 Participants Total of all reporting groups
Age, Continuous	27.0 years STANDARD_DEVIATION 6.4 • n=5 Participants	25.9 years STANDARD_DEVIATION 6 • n=7 Participants	26.5 years STANDARD_DEVIATION 6.2 • n=5 Participants
Sex: Female, Male Female	40 Participants n=5 Participants	47 Participants n=7 Participants	87 Participants n=5 Participants
Sex: Female, Male Male	45 Participants n=5 Participants	22 Participants n=7 Participants	67 Participants n=5 Participants
Region of Enrollment United States	85 participants n=5 Participants	69 participants n=7 Participants	154 participants n=5 Participants
systolic blood pressure	109.9 mmHg STANDARD_DEVIATION 11.4 • n=5 Participants	112.5 mmHg STANDARD_DEVIATION 12.1 • n=7 Participants	111.1 mmHg STANDARD_DEVIATION 11.8 • n=5 Participants
diastolic blood pressure	64.0 mmHg STANDARD_DEVIATION 6.8 • n=5 Participants	66.2 mmHg STANDARD_DEVIATION 7.5 • n=7 Participants	65.0 mmHg STANDARD_DEVIATION 7.1 • n=5 Participants
GRK5 Genotype GLN/GLN	85 Participants n=5 Participants	29 Participants n=7 Participants	114 Participants n=5 Participants
GRK5 Genotype GLN/LEU	0 Participants n=5 Participants	35 Participants n=7 Participants	35 Participants n=5 Participants
GRK5 Genotype LEU/LEU	0 Participants n=5 Participants	5 Participants n=7 Participants	5 Participants n=5 Participants

PRIMARY outcome

Timeframe: 2 exercise periods of 6 minutes each. 6 minutes of exercise before taking atenolol, and 6 minutes of exercise starting 2.5 hours after taking 25 mg of atenolol (2.5 hours + 6 minutes)

Population: There are 3 genotypes for GRK5, GLN/GLN, GLN/LEU, and LEU/LEU. A priori analysis plan was to compare reduction in heart rate among the 3 genotypes..

Outcome measures

Outcome measures
Measure	GLN/GLN n=114 Participants One of 3 genotypes for GRK5, GLN/GLN	GLN/LEU n=35 Participants One of 3 genotypes for GRK5, GLN/LEU	LEU/LEU n=5 Participants One of 3 genotypes for GRK5, LEU/LEU.
Reduction in Heart Rate 0, baseline	7.9 beats per minute Standard Deviation 7	6 beats per minute Standard Deviation 5.9	3.3 beats per minute Standard Deviation 5.4
Reduction in Heart Rate 2 minutes from baseline, 2 minutes exercise at 25W	9.6 beats per minute Standard Deviation 8.2	8.4 beats per minute Standard Deviation 7.7	7.4 beats per minute Standard Deviation 4.4
Reduction in Heart Rate 4 minutes from baseline, 2 minutes exercise at 50W	11.7 beats per minute Standard Deviation 7	10.9 beats per minute Standard Deviation 7.2	9.1 beats per minute Standard Deviation 3.4
Reduction in Heart Rate 6 minutes from baseline, 2 minutes exercise at 75W	14 beats per minute Standard Deviation 8	12.4 beats per minute Standard Deviation 9.1	10 beats per minute Standard Deviation 6.1

Adverse Events

White Participants--Atenolol

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Black Participants-Atenolol

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. C. Michael Stein

Vanderbilt University Medical Center

Phone: 615-936-3420

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place