Hypertension
Conditions
Keywords
hypertension, antihypertensive drug, pharmacogenetics, genetics, blood pressure, glucose
Brief summary
There are many medications available for the treatment of high blood pressure (hypertension), but finding the right one for a specific patient can be challenging. In fact, it is estimated that less than 50% of people with hypertension have their blood pressure under control. The hypothesis is that genetic differences between individuals influence their response to antihypertensive medications. This study is aimed at determining the genetic factors that may influence a person's response to either a beta-blocker or a thiazide diuretic. The hope is that through this research, the investigators may someday be able to use an individual's genetic information to guide the selection of their blood pressure medicine, leading to better control of blood pressure, and less need for the current trial and error process.
Detailed description
The proposed work should help move toward the long-term goal of selection of antihypertensive drug therapy based on a patient's genetic make-up. Hypertension (HTN) is the most common chronic disease for which drugs are prescribed, and the most prevalent risk factor for heart attack, stroke, renal failure and heart failure. Responses to antihypertensive drug therapy exhibit considerable interpatient variability, contributing to poor rates of HTN control (currently about 40-50% in the US), and frequent nonadherence and dropout from therapy. We propose to identify genetic predictors of the antihypertensive and adverse metabolic responses to two preferred and pharmacodynamically contrasting drugs, a beta-blocker (metoprolol) and a thiazide diuretic (chlorthalidone) in a sequential monotherapy design in 400 hypertensive individuals. Data collected will include home and clinic blood pressure, blood samples for testing for adverse metabolic effects and other biomarkers, RNA, and DNA and urine sample. We will conduct genome-wide association single nucleotide polymorphism (SNP) genotyping and data from the study will be used for replication of findings from the previous PEAR trial, along with new discoveries. The primary aims are to define the genetic determinants of the antihypertensive response and adverse metabolic responses (e.g. changes in glucose, triglycerides and uric acid). The proposed research is significant because genetically-targeted antihypertensive therapy could lead to dramatically higher response rates and fewer adverse effects than the usual trial-and-error approach. This would likely lead to higher rates of HTN control, less need for polypharmacy, reduced health care costs, and improved outcomes.
Interventions
Metoprolol 50 mg twice daily titrated to 100 mg twice daily Note: due to discontinuation of the manufacture of chlorthalidone 15 mg, effective Jan 1, 2013; the starting dose of chlorthalidone will be 25 mg 4 times per week (Mon, Wed, Thur, Sat) with subsequent titration to 25 mg daily.
Chlorthalidone 25 mg 4 times per week titrated to 25 mg daily
Sponsors
Study design
Eligibility
Inclusion criteria
* An average seated home diastolic blood pressure (DBP) \> 85 mmHg and \< 110 mmHg and home systolic blood pressure (SBP) \< 180 mmHg. * Subjects must also have an average seated (\> 5 minutes) clinic DBP between 90 mmHg and 110 mmHg and SBP \< 180 mmHg
Exclusion criteria
* Secondary forms of hypertension (HTN) (including sleep apnea) * Isolated systolic HTN * Other diseases requiring treatment with BP lowering medications * Heart rate \< 55 beats/min (for metoprolol only) * Known cardiovascular disease (including history of angina pectoris, heart failure, presence of a cardiac pacemaker, history of myocardial infarction or revascularization procedure, or cerebrovascular disease, including stroke and TIA) * Diabetes mellitus (Type 1 or 2) * Renal insufficiency (serum creatinine \> 1.5 in men or 1.4 in women) * Primary renal disease * Pregnancy or lactation * Liver enzymes \> 2.5 upper limits of normal * Current treatment with NSAIDS, cyclooxygenase-2 (COX2) inhibitors, oral contraceptives or estrogen.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Blood Pressure From Baseline to Treatment | after 6-8 weeks of treatment | Response to blood pressure medication will be assessed by measuring blood pressure before and after treatment |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Adverse Metabolic Effects | after 6-8 weeks treatment | Change in glucose after treatment with study medication |
Countries
United States
Participant flow
Recruitment details
The first subject was recruited on 8/10/10 and the final patient was recruited on 9/30/2013. Subjects were recruited from family medicine clinics and were identified through providers daily schedules, medical records, and encounter forms.
Pre-assignment details
Healthy volunteers with mild to moderate primary hypertension between the ages of 18-70 were eligible for the study. Subjects were washed-out from their hypertension medication prior to beginning study protocol. Participants with elevated systolic blood pressure greater than 180 mmHg after wash-out were excluded from the study.
Participants by arm
| Arm | Count |
|---|---|
| Metoprolol + Chlorthalidone This group was assigned to the following: Metoprolol tartrate 50 mg twice daily for two weeks. After two weeks subjects will be seen in clinic and will have the dose doubled to 100 mg twice daily if either their HBP average or OBP is \> 120/70 mmHg. They will continue on this dose for an additional 6 weeks. Then will washout from all study medication. After washout, participants will initiate chlorthalidone 25 mg four times per week (Monday, Wednesday, Thursday, Saturday) for two weeks, then 25 mg daily of chlorthalidone for 6 weeks.
Metoprolol: Metoprolol 50 mg twice daily titrated to 100 mg twice daily
Chlorthalidone: Chlorthalidone 25 mg 4 times per week titrated to 25 mg daily
Note: due to discontinuation of the manufacture of chlorthalidone 15 mg, effective Jan 1, 2013; the starting dose of chlorthalidone will be 25 mg 4 times per week (Mon, Wed, Thur, Sat) with subsequent titration to 25 mg daily. | 839 |
| Total | 839 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Metoprolol 8 Weeks | Physician Decision | 470 |
| Washout 2 Weeks | Physician Decision | 46 |
Baseline characteristics
| Characteristic | Metoprolol + Chlorthalidone |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 839 Participants |
| Age, Continuous | 50.3 years STANDARD_DEVIATION 9 |
| Region of Enrollment United States | 839 participants |
| Sex: Female, Male Female | 429 Participants |
| Sex: Female, Male Male | 410 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 114 / 839 |
| serious Total, serious adverse events | 3 / 839 |
Outcome results
Change in Blood Pressure From Baseline to Treatment
Response to blood pressure medication will be assessed by measuring blood pressure before and after treatment
Time frame: after 6-8 weeks of treatment
Population: All patients with antihypertensive response data. 282 patients completed all 3 study periods. 369 patients completed only period 1. 328 patients completed only period 3.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Metoprolol + Chlorthalidone | Change in Blood Pressure From Baseline to Treatment | diastolic blood pressure response | -7.56 mmHg | Standard Deviation 6.39 |
| Metoprolol + Chlorthalidone | Change in Blood Pressure From Baseline to Treatment | systolic blood pressure response | -11.70 mmHg | Standard Deviation 9.51 |
| Metorprolol Only | Change in Blood Pressure From Baseline to Treatment | diastolic blood pressure response | -7.97 mmHg | Standard Deviation 6.48 |
| Metorprolol Only | Change in Blood Pressure From Baseline to Treatment | systolic blood pressure response | -7.45 mmHg | Standard Deviation 9.85 |
| Chlorthalidone Only | Change in Blood Pressure From Baseline to Treatment | diastolic blood pressure response | -7.68 mmHg | Standard Deviation 5.84 |
| Chlorthalidone Only | Change in Blood Pressure From Baseline to Treatment | systolic blood pressure response | -13.65 mmHg | Standard Deviation 9.55 |
Adverse Metabolic Effects
Change in glucose after treatment with study medication
Time frame: after 6-8 weeks treatment
Population: All patients with change in glucose data
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Metoprolol + Chlorthalidone | Adverse Metabolic Effects | glucose response to metoprolol (n=365) | 1.02 mg/dL | Standard Deviation 9.83 |
| Metoprolol + Chlorthalidone | Adverse Metabolic Effects | glucose response to chlorthalidone (n=318) | 5.12 mg/dL | Standard Deviation 10.6 |