Β-Blockers And Hypertension: Where Are The Data?

Compelling indications in JNC7 that warrant β-blocker therapy include heart failure with reduced ejection fraction (HFrEF)^2,3, acute myocardial infarction (AMI)⁴, high coronary disease risk, and diabetes. While there is long-standing evidence supporting the use of β-blockers in the treatment of hypertension^5,6, the 2007 American Heart Association (AHA) Scientific Statement on Hypertension Management considers β-blockers 3^rd or 4^th line options for the chronic treatment of hypertension in patients without a compelling indication.⁷

β-blockers have been compared against one another in the setting of HF¹⁴ and AMI.¹⁵However, studies comparing different β-blockers in hypertensive patients without compelling indications are lacking.  Parker and colleagues sought to address this issue by comparing atenolol with metoprolol tartrate in the setting of hypertension without known CAD, HF, or MI.¹⁶ This retrospective cohort study utilized electronic medical records and health plan data from the Cardiovascular Research Network Hypertension Registry. The registry includes adults identified as having hypertension between 2000 and 2009 at three large integrated health care delivery systems. The study aimed to compare the incidence of MI, HF, and stroke in adult patients with high blood pressure who were new users of atenolol versus metoprolol tartrate.  Admittedly, metoprolol succinate and carvedilol would have been more desirable comparators to atenolol because of their positive outcomes shown in HFrEF patients.^4,5  However, metoprolol tartrate was the only β-blocker prescribed frequently enough for inclusion in the analysis.

Over a mean follow-up of 5.2 years, the study found no difference between atenolol and metoprolol tartrate in reducing MI, HF, stroke, or any cardiovascular (CV) event (Table). Two methods were used for data analysis, multivariable cox proportional hazard regression (N=120,978) and propensity score matching (N=22,352), both of which found no significant difference.

^a N=11,176

^b N=109,802
^cAdjusted for year of β-blocker therapy initiation, age, sex, number of visits in prior year, systolic BP at start of β-blocker therapy, lipid disorder, diabetes, chronic kidney disease, and if using other antihypertensive medications.

Baseline BP was 144.2/81.3 mmHg prior to taking atenolol (n=6907) and 143.3/80.2 mmHg prior to taking metoprolol tartrate (n=7010). The reduction in BP over a 6-month follow up was 7.7/4.7 mmHg for atenolol versus 6.7/3.4 mmHg for metoprolol tartrate. Differences in the baseline and change in diastolic BP over the 6-month follow-up were statistically different; however, both groups had a similar mean achieved blood pressure after treatment, so the small difference at baseline is not likely to be clinically important.

This study found no difference between atenolol and metoprolol tartrate in reducing major CV events. Can the argument be made that all β-blockers are inferior options for the treatment of hypertension?   Which is the “best” β-blocker to use for hypertension may no longer be the right question.  We anticipate that JNC8 will mirror the AHA recommendation to use β-blockers as a 3^rd or 4^th line anti-hypertensive in patients without angina, a history of myocardial infarction, or left ventricular dysfunction with or without heart failure symptoms.   For the patient who presents with uncontrolled hypertension, at what point do you consider using a β-blocker?  Which β-blocker do you prefer?