Cardiovascular disease affects 33% of adults in the world and as such is the largest epidemic ever known to mankind, according to Prof Neil Poulter, co-director of the International Centre for Circulatory Health.
Hypertension is the biggest single risk factor for CVD. An estimated 10.7 million people died as a result of CVD in 2018, and the incidence is increasing dramatically year-on-year, said Prof Poulter.
In South Africa, CVD is among the top three causes of death. According to Dr Liesl Zühlke, president of the South African Heart Association, about 195 South Africans die every day due to CVD and the number is expected to increase.
There are numerous reasons for this, said Dr Zühlke. One of the main reasons is urbanisation. Studies by the World Heart Association show that urbanisation – especially in low- and middle-income countries (LMICs) – has ‘facilitated the globalisation of unhealthy lifestyles such as tobacco use, unhealthy diets, physical inactivity and harmful use of alcohol’.
The National Health and Nutrition Examination Survey (SANHANES), conducted by the Human Sciences Research Council in 2012 and released in 2014, showed that an alarming number of South Africans in rural and informal urban areas – more than 40% of the population – are nutritionally deficient, with low dietary diversity, and low food security due to socio-economic factors.
In urban areas in higher income regions where food diversity was high, foods eaten were high in fat and sugar, causing obesity and other health problems such as hypertension, dyslipidaemia and diabetes. SANHANES also showed that South Africans have a high prevalence of hypertension (24.8%), dyslipidaemia (17.5%), and diabetes (15.3%).
Where should we start?
Prof Poulter cautioned that 50% of the damage caused by high blood pressure (BP) occurs below the accepted definition of hypertension. This means that we need a population-based strategy to shift the whole population’s BP down.
How can we achieve this?
- By creating awareness
The prevalence, awareness, treatment, and control of hypertension in rural and urban communities in high- (HICs), middle-, and low-income countries (LMICs) or PURE study (2003-2009), showed that about 46% of people with hypertension are aware that they have the condition.
Awareness, treatment, and control of hypertension were higher in urban communities compared with rural ones in LICs and LMICs, but similar for other countries. Low education was associated with lower rates of awareness, treatment, and control in LICs, but not in other countries.
If we want to prevent CVD, we have to improve awareness because we cannot treat what we don’t know about, said Prof Poulter. To this end, the IHS introduced May Measurement Month in 2017, the largest multinational CV screening programme ever.
During the campaign, 1.2 million people were screened and 150 000 hypertensives were diagnosed but were not on any treatment. Furthermore, they identified 100 000 people (40%) who were on treatment, but uncontrolled.
During the 2018 campaign, 1.5 million people were screened in 89 countries. About 220 000 were diagnosed with hypertension but were not on any treatment and 110 000 (40%) who were on treatment were uncontrolled.
- By closing treatment gaps
Controlling BP with medication is unquestionably one of the most cost-effective methods of reducing premature CVD morbidity and mortality, said Prof Poulter, but only 40% of patients are treated. Only about 13% globally have controlled hypertension. In South Africa, 91% of patients (who meet the accepted definition) have uncontrolled hypertension.
One of the reasons why controlled hypertension figures are so low is because monotherapy is often inadequate, said Prof Poulter. Most patients around the world receive monotherapy. The majority of patients require two or more therapies.
Which two drugs are best?
Guidelines are often confusing, he noted. Most recommend a combination of either an angiotensin-converting-enzyme (ACE) inhibitor or an angiotensin II receptor blockers (ARB), in combination with a calcium channel blocker (CCB) or a diuretic (D).
In his opinion an ACE inhibitor or an ARB in combination with a CCB is the best combination for White patients.
But, noted Prof Poulter, none of the guidelines are clear on what combinations work most effective in Black, South Asian, Chinese populations or patients from the Far East due to a lack of clinical trials. Bioethniticity plays a major role in the efficacy of treatment, he stressed.
To address this gap, a randomised controlled study evaluating the efficacy of ACE inhibitors and ARBs in combination with a D in Black patients from Africa were recently completed. The Comparing the efficacy of three ‘free’ (separate pills) combinations of two anti-hypertensive agents on 24-hour ambulatory systolic blood pressure in black African hypertensive patients or CREOLE Study, conducted in six sub-Saharan African countries (n=700) were recently completed.
The study compared the efficacy of the following combinations: Perindopril plus amlodipine, perindopril plus hydrochlorothiazide and amlodipine plus hydrochlorothiazide. The primary endpoint was changes in ambulatory systolic BP measurement from baseline to six months. The results will be released later this year. A study among patients from the Far East will also be launched in 2019.
The new European Society of Cardiology (ESC) arterial hypertension guideline, which Prof Poulter supports, recommends the following:
- The initiation of treatment in most patients with a single-pill combination comprising two drugs, to improve the speed, efficiency, and predictability of BP control
- Preferred two-drug combinations are a renin-angiotensin system (RAS) blocker with a CCB or a D. A Beta-blocker (BB) in combination with a diuretic or any drug from the other major classes is an alternative when there is a specific indication for a BB eg angina, post-myocardial infarction, heart failure, or heart rate control
- Use monotherapy for low-risk patients with stage 1 hypertension whose systolic BP (SBP) is <150mmHg, very high-risk patients with high– normal BP, or frail older patients
- The use of a three-drug single-pill combination comprising a RAS blocker, a CCB, and a D if BP is not controlled by a two-drug single-pill combination
- The addition of spironolactone for the treatment of resistant hypertension, unless contraindicated
- The use of other classes of antihypertensive drugs in the rare circumstances in which BP is not controlled by the above treatments.
Free vs single-pill combinations: Which is best?
Single-pill combinations improve adherence (20%). They are also more effective at achieving BP control than free pills, have reduced side-effects, improve CV protection and are more cost-effective, said Prof Poulter.
What about statins?
Prof Poulter recommended that fourth- or fifth-line BP lowering medication is not important; rather, it is recommended that hypertensive patients – especially those with a 10% CV risk – should be placed on a statin independent of their cholesterol levels.
Recommendations for subgroups
Prof Poulter recommended the following treatment for subgroups:
- By promoting healthy lifestyle choices
According to Prof Poulter, most guidelines recommend non-pharmacological therapies such as lifestyle changes (healthy diet, exercising, reducing alcohol, saturated fats and salt intake, decrease body weight, increase potassium intake [more fresh fruit and vegetables], incorporate stress-release practices and quit smoking).
In the past, doctors treated patients based on how high the mercury goes on a manual arm cuff, ignoring the object attached to the arm. If we want to prevent CVD effectively, we have to look at the patient holistically, concluded Prof Poulter.