President of the Nigerian Hypertension Society and physician cardiologist at University of Ilorin Teaching Hospital, Kwara State, Prof Ayodele Omotoso, tells LARA ADEJORO why hypertension is increasing in the country
What is hypertension?
Hypertension is basically when the blood pressure is persistently above the designated upper limit of normal. To give a specific definition for hypertension abstractly will be difficult, but in a nutshell, it is when the blood pressure is persistently reading above the upper limit of the normal range. When we talk of the normal range, from epidemiological studies, the normal blood pressure is put at 90 systolic (for the top number) to 60 diastolic (for the bottom number) to 140 systolic and 80 diastolic. Anything that is persistently higher than 140 over 90 is considered elevated, and when it is established, it is considered to be hypertension. When they say 140 to 160, they say it is stage one hypertension; 90 over 110 is still stage one, but when it is higher than that, it is stage two, though there are different classifications used by different organisations. Some other classifications are even saying the lower, the better. When it is 130 mm of micro systolic, some classify that as upper normal or prehypertension or 80 to 85/90. Anything that is moving towards 90 is regarded as prehypertension or high-normal, and if you see people at that level, that is when to propose lifestyle modification. You advise them on lifestyle modifications to prevent it from becoming fully established.
Does it matter when the blood pressure is checked?
On the time to check the numbers, you must be consistent with the time you check your blood pressure numbers. If you check your numbers in the mornings, you have to do it every morning consistently; if it is in the evenings, you have to do it in the evening always so that you can interpret it appropriately because we also have diurnal variations. We expect that when a person is asleep, the blood pressure is supposed to go down and when he is waking up, the blood pressure will go up.
What are the causes and risk factors associated with hypertension?
There are two types of hypertension – the primary or essential hypertension and the secondary hypertension. Primary hypertension constitutes about 90 to 95 per cent of all cases of hypertension, and the remaining five per cent is called secondary hypertension. For primary hypertension, unfortunately, the cause is unknown, while secondary hypertension is due to specific diseases like kidney disease, endocrine disease, and anatomic abnormalities. Secondary hypertension is common among young ones. Primary hypertension is common in adults. There is no specific cause, but we do know that there are some risk factors, and essentially among these risk factors are excessive salt intake, excessive alcohol intake, obesity, a sedentary lifestyle, some discretionary foods, and smoking. Apart from these lifestyles contributing to the development of hypertension, they are also called risk factors for non-communicable diseases. Heredity plays a role as well. If someone has a hypertensive parent, he should also watch out, and the risk increases if the two parents are hypertensive. Developing hypertension is an interplay of genetic and environmental factors.
What are the signs and symptoms to look out for?
Unfortunately, primary hypertension is asymptomatic until complications have set in, and that is why we describe hypertension as a silent killer. The person may be walking around with hypertension and may not know it, and the first presentation may be sudden death, he may develop a stroke, or a heart attack, without knowing previously that he has hypertension. I have had patients who say they don’t have headaches, so they should not have hypertension, but headache is not a symptom of straightforward hypertension. However, it can occur when complications of hypertension have set it.
What are the complications?
No organ in the body cannot be affected by hypertension. It affects the eyes and causes blindness. It can affect the brain when it causes stroke, and it can affect the heart. Hypertension is a risk factor for coronary artery disease, which, unfortunately, is becoming common in our environment; we see more people having chest pain, and before you know it, they drop dead. Hypertension in Africa is the most common cause of heart failure. Hypertension can lead to chronic kidney disease. The complications of hypertension cut across all the organs in the body, and that is why it is important to prevent it or ensure treatment. Once a person is diagnosed with hypertension, that person will be on one form of treatment or the other for life. The treatment of hypertension is not just about medications alone, other things come in; lifestyle modification is a form of treatment. There is something we call primordial prevention, which means that the person has not developed hypertension, but has already started lifestyle modifications, particularly those who are programmed to be hypertensive because of hereditary or other possible effects of the risk factors.
Is it controllable?
Hypertension is controllable, but it is not curable. Managing hypertension is like two people wrestling, and one can pin down the other. The one that has pinned down the opponent, if he doesn’t want the opponent to come up, keeps pinning down his opponent. For hypertension, this can be achieved with both lifestyle modifications and medications. If they (the patient) don’t want hypertension to return, they must maintain what they are doing to pin it down. Hypertension is only curable if it is a secondary type of hypertension. If you remove that causative disease, there is a likelihood that you will be able to cure it, provided it has not caused further damage to the organs. It is paradoxical to note that CKD from other causes can cause secondary hypertension, and hypertension can cause CKD, so it is intertwined.
What is the prevalence rate of hypertension in Nigeria?
The prevalence of hypertension in Nigeria from the first national survey that was done almost 30 years ago by the Akinkugbe’s group gave a prevalence of about 11 per cent in the adult population. However, today, the prevalence of hypertension in Nigeria and globally has increased, and the rate of increase is highest in the low-middle-income countries, especially in sub-Saharan Africa such that the prevalence is about 38 to 42 per cent in the adult population in Nigeria, which is very high. If you look at the various complications, it means that the burden is very high. When you disaggregate the figures to specific geopolitical zones, what you eventually have is such that the South-East has the highest prevalence, and it depends on the figure you are looking at. Some say after the South-East, it is the North-East, then the South-South, before moving to the South-West, and then the North-West and the North-Central, but we have other figures and publications showing that the highest prevalence is in the South-East, then the South-South and the South-West before going to the North-East.
From the national survey, the figure ranged from 30 to 32 to 44.7 per cent from different series. The highest prevalence of the available figures shows the South-East geopolitical zone has the highest with almost 52 per cent, and the North-Central is the lowest with 20.9 per cent. This series that I am quoting shows the South-East as number one, followed by the South-South with 44 per cent, the South-West, especially the Lagos area, has 42 per cent; followed by the North-East with 27 per cent; and the North-West with about 26 per cent or approximately 27 per cent, and the North-Central with 20 per cent. It all depends on the series, but there is no doubt that the prevalence is high.
How did you arrive at these figures, and what could be the reasons for the high number, especially in the South-East?
It will be difficult to just say why the prevalence is high in a particular zone until you interrogate further because it is an observation from epidemiological studies. You have to look comparatively into the risk factors. Are the risk factors higher in certain areas than the others? The question will only be answered with further interrogation into the reasons, but it most likely has to do with the prevalence of the respective risk factors, and one has to study that against other NCDs like diabetes. There is a need to study why it is low in certain areas, and why it is high in certain areas. It has to be looked into to know if it is stress-related, dietary, or genetic-related.
Is it common in urban or rural areas, and what is the male-to-female ratio?
In the past, we thought it was commoner or higher in the urban areas, but from recent figures, it is looking like everything is levelling up. The difference is almost marginal, but before recently, that dichotomy was there that it is higher in urban areas than rural areas. The prevalence is getting high in the rural areas. There have been studies showing that the rural and urban areas are almost the same. On the male-to-female ratio, it depends on the series. Let us even look at cardiovascular disease, specifically coronary artery disease; it is higher in males, but at menopause, it levels out. Knowing if hypertension is higher in males or females depends on the study population. If you have more females in your study population, of course, there will be more among them, but the tendency is to look at the complications of hypertension being higher in males, but it gets to a stage in life, physiologically, that it is also as it is in the males and the females.
Some believe that hypertension is commoner in adults than in young people. Is this changing?
The more advanced in age a person gets the more the prevalence. So, in the older age group, hypertension is commoner, so it tracks with age, whereas the prevalence of hypertension in children may be between the range of 10 per cent, while in adults, we are talking of 30 to 40 per cent. Even if you look at older people in the range of above 50 or 60 or above 70, the hypertension prevalence goes up, and you have it more commonly in the elderly than in younger people. It jacks up with age, not to say that it is only adults or old people who have it, but the prevalence goes higher in elderly people.
Is it true that stress and substance abuse are risk factors for hypertension?
There are different types of stress: physical, psychological, or emotional stress. If you look at the pathophysiology of stress and its impact on the cardiovascular system, it is easier to say that if you are under persistent stress that will make your adrenaline persistently high, you can say it can lead to hypertension because adrenaline is the hormone that you pour from the adrenal gland or the sympathetic system, and it is described as the hormone of fright, fight and flight. It prepares the body to either fight a danger or run away from it. If a person is persistently under that influence, we can theoretically say so. However, I have a rider to that; not everybody who is stressed will develop hypertension, and not everybody who has hypertension is under stress. You do not have to be under stress to become hypertensive. For substance abuse, there are different types of substance. We have said that the injudicious use of alcohol is one of the risk factors. If they are psychoactive agents like cannabis or cocaine, they have specific hemodynamic effects. Cocaine, for instance, works in addition to whatever effects it gives to those people. It affects the cardiovascular system such that the person is always active, and on the move, and all those can affect the blood vessels, blood pressure, and cardiac output. But it is not as if all substance abusers are hypertensive. But again, in people that are programmed to have it, it is not invariable.
What are the lifestyle changes one needs to inculcate as an adjunct to treatment to fight hypertension?
If you are a smoker, you have to stop smoking. Someone who drinks alcohol must reduce or stop drinking, somebody who is obese should work hard to lose weight, and somebody who lives a sedentary lifestyle should work at it, and this can be an evening walk in the neighbourhood. Reduce salt intake; the moment you taste salt in your food, it means that the salt is too much. Also, you need to worry less, leave what you cannot change and that is where faith comes in.
Like some other drugs, inflation has caused a hike in the prices of medications for the treatment of hypertension. What are the implications of this on patients, and what can the government and stakeholders do to reduce this burden?
The costs of different medications have gone up, and within the past 12 months, you can talk of as high as a 200 to 300 per cent increase. I interacted with a patient recently who asked that his medications be changed, not because the medications were not working, but because he could no longer afford the medications. He started with about N2,500 per month, and about two weeks ago, that same medication was going for N22,000. You can then imagine someone who is on a minimum wage of N30,000, and you are asking him to take one of many medications that they will be on for N22,000; the patient will not take the medication. That will force patients to start looking for alternatives that they think are cheaper, which are native concoctions, and all forms of herbal tea, and if all those are not proven to be efficacious, they may lead to complications. We are particularly worried about the damage the concoctions can cause to other organs like the kidney, liver, heart, and even the brain. One of the unfortunate dangers is that we will be seeing more and more of the complications of hypertension because the patients are not able to buy the medications. Health insurance is the answer; getting as many more people as possible enrolled into the insurance scheme, and then the patients will pay less. We should be working towards manufacturing most of these drugs locally to reduce the costs of medications. Many of the drug companies are leaving Nigeria, and we need to think outside of the box to see how drugs can be manufactured locally, and expand the scope of coverage of the insurance scheme.
