We have discussed various lifestyle diseases over past several weeks. While obesity has dominated as a theme throughout this series, more recently we have shifted focus to other critical issues such as diabetes and cholesterol. In similar vein, this particular edition shall do a deep dive into hypertension.
Hypertension is an extremely common condition. About 1 billion individuals globally suffered from high blood pressure (BP) in 2016, and the number is estimated to rise to over 1.5 billion by 2025, with over 200 million of them being in India.
A study in 2014, the largest one of its kind in India, by Anchala R, Kannuri NK, Pant H, Khan H and others from the Public Health Foundation of India (PHFI) estimates the prevalence of hypertension in India at a mind-boggling 29.8% of the adult population.
If one is to estimate:
India’s total population is presently 1,370 million; 71.4% are over 15 years of age. Assuming that the country has roughly 950 million adults, over 280 million can be presumed to be hypertensive.
Further, the average blood pressure (BP) rises with age. About 80% of individuals aged 75 years or more have hypertension which requires treatment (Go et al, Circulation 2013).
It came as not much of a surprise then, when the Global Burden of Disease Study found that of all the risk factors that contributed to mortality, hypertension is responsible for the maximum attributable risk, accounting for close to half of all strokes, one-fourth of heart attacks and 13.5% of all deaths. This data makes one very uncomfortable, especially as high BP is usually asymptomatic and is found in nearly every household.
What is Hypertension?
It is a clinical condition characterized by high blood pressure (BP), i.e., higher than the upper limit of normal. For several decades, this was BP more than 140/90, meaning over 140 mm Hg systolic or 90 mm Hg diastolic BP. According to this definition, about 33% of the urban population and 25% of rural population in India are hypertensive. However, awareness that one has high BP is quite low - only about 1/4th of rural and 42% of urban patients know that they have the condition, about two-thirds of those are on treatment and barely 1 in 10 of rural and 1 in 5 of urban patients have BP well under control. Obviously, this is a huge public health problem and people need to be aware of the need to check their blood pressure, even if they have no symptoms at all.
As has been reported occasionally in the lay press, in 2017, the American College of Cardiology (ACC) modified the cut-off for diagnosing hypertension to 130/80 mm Hg, making an extra 14% of the adult population hypertensive in the US as compared to earlier (46% of all adults, compared to 32% before the 2017 criteria).
While the European Society of Cardiology (ESC) hasn’t changed their diagnostic criteria, they have also recommended more stringent targets (aiming for 130/80 instead of 140/90) last year. All this has made life tougher for physicians and patients alike.
The reasons for this change are many. It is now established that BP above 115/75 leads to increased risk of Cardiovascular disease (CVD), and that the risk doubles with every 20/10 mm Hg increase. This means that the risk of CVD doubles at 135/85, and quadruples at 155/95 mm Hg compared to 115/75. Further, new drugs for high BP are more effective, longer acting (usually once daily dose), and safer, making it possible to lower BP with lesser side effects. And that’s why combination pills (pills containing 2-3 medicines instead of just one, as was the norm earlier) are becoming popular.
Of course, this means a lot more people need medicines (usually >1) for high BP, and those already on treatment need more for adequate control, as defined presently. Apart from the recurring cost of treatment, follow-up and investigations, there is also the difficulty of persuading apparently healthy, asymptomatic individuals to agree to a lifetime of medical therapy.
Is There a Way to Prevent Hypertension?
While a discussion on the pros and cons of the newer criteria is outside the scope of this piece, it is critical to know what the strategies to lower BP without medicines are.
As usual, lifestyle modifications are extremely effective in lowering BP. The most effective approach is weight loss. 10 kg weight loss is associated with a reduction in BP of 5-20 mm Hg. Following the DASH diet (Dietary Approaches to treat Hypertension) brings about 8-14 mm reduction, while dietary sodium restriction is also associated with 2-8 mm Hg fall. Regular physical activity (4-9 mm) and moderation of alcohol intake (2-4 mm) are also rewarding.
The net result is that regular exercise and a healthy diet while maintaining an optimal body weight can bring about BP reductions of up to 10-20 mm Hg, which is substantially more than the effect of most single anti-hypertensive drugs. This means that most people on treatment can reduce the number of required drugs by at least 1 agent (most people need 2-3 agents), while those on a single drug can manage without any medicine whatsoever.
These lifestyle changes are not easy, but the reward is better health, lesser chances of disease and the avoidance of medical therapy for decades.
In summary, hypertension is being diagnosed at lower BP levels than earlier, due to increasing evidence regarding the harms of persistently elevated blood pressures and the availability of safer and more effective medicines. It is important to know one’s BP, as lifestyle modification can go a long way in reducing average BP and reducing the risk of CVD.
This is a recurring column published every Sunday. Click here to view my other articles on health, nutrition and exercise.
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