DOI: 10.25934/pr00008349
title: The efficacy of beta-blockers on morbidity and mortality endpoints in black hypertensive patients: A meta-analysis

description: Hypertension is considered the most common non-communicable disease globally. In 2015, it was estimated to affect 20.1% and 24.1% of women and men respectively, resulting in a global prevalence of approximately 22%. In Africa, the prevalence of hypertension has been estimated to be as high as 30%, yet blood pressure control is dismal, with awareness of diagnosis at 27%, and of these, 18% are treated, with only 7% controlled on treatment.

The majority of hypertensive patients will require pharmaceutical therapy and lifestyle interventions to achieve optimal blood pressure control. In the past three decades, five major medicine classes were routinely recommended for the treatment of hypertension. These included the angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), beta-blockers, calcium channel blockers (CCBs), and the thiazide and thiazide-like diuretics.

Contemporary clinical guidelines on the management of uncomplicated essential hypertension have downgraded the indication of beta-blocker therapy, to be used only when cardiovascular conditions (coronary artery disease (CAD), Heart failure, Arrhythmias and in young women planning on pregnancy) dominate. This has been supported by evidence suggesting that beta blockers fail to reduce the central aortic pressure and hence are associated with increased stroke events. Despite the widespread awareness of the different efficacy of hypertensive therapy in the various races, this recommendation has been broadly applied to all racial groups. 

A sub-analysis of the LIFE study found that the hazard ratio of Losartan compared to Atenolol in reducing the primary endpoint of the study (cardiovascular death, stroke, myocardial infarction) favored Atenolol in African patients [1.667 (95% CI 1.043-2.661) (Alderman, et al).

Additionally, it is widely accepted that African patients are generally under-represented in the literature. "Although there are many possible combinations of blood pressure (BP)-lowering therapies, the best combination for the black population is still a subject of debate because no large randomized controlled trials have been conducted in this group to compare the efficacy of different combination therapies to address this issue." (Ojji et al).

The second study does not include Beta-blockers as one of the three anti-hypertensive treatments but supports the notion that more studies are required looking specifically at the African population.

We are of the opinion that the exclusion of beta-blockers as a potential therapeutic option in black patients primarily comes from the lack of large randomized controlled trials (RCTs) investigating the efficacy of beta-blockers in treating hypertension in black patients. The majority of RCTs where evidence for beta-blocker therapy in hypertension arose were largely dominated by non-black populations. Thus, the lack of recommendation for beta-blocker therapy in black patients results from the lack of data rather than evidence against beta-blocker use in black patients. 

We therefore hypothesise that a systematic review and a meta-analysis of pooled individual patient data of recent and old RCTs (with a focus on black patients), investigating the efficacy of new and old beta-blockers in the treatment of hypertension may reveal new insights into the role of beta-blockers in the treatment of hypertension in the black population. Furthermore, the role of new beta-blockers in the treatment of hypertension in all populations is still to be defined as there are currently no large RCTs investigating the efficacy of these new therapies. 

Through our preliminary literature search, your research work has been identified as a possible source to retrieve the Individual patient data for inclusion in our systematic review and meta-analysis.