PREVENTION OF HYPERTENSION :
The low prevalence of hypertension in some communities indicates that hypertension is potentially preventable. The WHO has recommended the following approaches in the prevention of hypertension:
- Primary prevention
- Secondary prevention
PRIMARY PREVENTION :
Although control of hypertension can be successfully achieved by medication (secondary prevention} the ultimate goal in general is primary prevention. Primary prevention has been defined as “all measures to reduce the incidence of disease in a population by reducing the risk of onset. The earlier the prevention starts the more likely it is to be effective.
In connection with primary prevention, terms such as “population strategy” and “high-risk strategy” have become established. The WHO has recommended these approaches in the prevention of hypertension. Both the approaches are complementary.
POPULATION STRATEGY :
The population approach is directed at the whole population, irrespective of individual risk levels. The
concept of population approach is based on the fact that, even a small reduction in the average blood pressure of a population would produce a large reduction in the incidence of cardiovascular complications such as stroke and CHD. The goal of the population approach is to shift the community distribution of blood pressure towards lower levels or “biological normality”. This involves a multifactorial approach, based on the following non-pharmacotherapeutic interventions ;
- NUTRITION : Dietary changes are of paramount importance. These comprise : {i) reduction of salt intake to an average of not more than 5 g per day {ii) moderate fat intake {iii) the avoidance of a high alcohol intake, and {iv) restriction of energy intake appropriate to body needs.
- WEIGHT/OBESITY REDUCTION : The prevention and correction of over weight/obesity {Body Mass Index greater than 25) is a prudent way of reducing the risk of hypertension and indirectly CHD; it goes with dietary changes.
- EXERCISE PROMOTION : The evidence that regular physical activity leads to a fall in body weight, blood lipids and blood pressure goes to suggest that regular physical activity should be encouraged as part of the strategy for risk-factor control.
- BEHAVIOURAL CHANGES : Reduction of stress and smoking, modification of personal life-style, yoga and transcendental meditation could be profitable.
- HEALTH EDUCATION : The general public require preventive advice on all risk factors and related health behaviour. The whole community must be mobilized and made aware of the possibility of primary prevention.
- SELF-CARE : An important element in community-based health programes is patient participation. The patient is taught self-care, i.e., to take his own blood pressure and keep a log-book of his readings. By doing so, the burden on the official health services would be considerably reduced. Log-books can also be useful for statistical purposes and for the long-term follow-up of cases
HIGH-RISK STRATEGY :
This is also part of primary prevention. The aim of this approach is “to prevent the attainment of levels of blood pressure at which the institution of treatment would be considered. This approach is appropriate if the risk factors occur with very low prevalence in the community.
Detection of high-risk subjects should be encouraged by the optimum use of clinical methods. Since hypertension tends to cluster in families, the family history of hypertension and “tracking” of blood pressure from childhood may be used to identify individuals at risk.
SECONDARY PREVENTION :
The goal of secondary prevention is to detect and control high blood pressure in affected individuals. Modern antihypertensive drug therapy can effectively reduce high blood pressure and consequently, the excess risk of morbidity and mortality from coronary, cerebrovascular and kidney disease. The control measures comprise:
EARLY CASE DETECTION :
Early detection is a major problem. This is because high blood pressure rarely causes symptoms until organic damage has already occurred, and our aim should be to control it before this happens. The only effective method of diagnosis of hypertension is to screen the population. But screening, that is not linked to follow-up and sustained care, is a fruitless exercise. It is emphasized that screening should not be initiated if health resources for treatment and follow-up are not adequate.
In the developed countries, mass screening is not considered essential for the adequate control of blood
pressure in the population. In Europe, the large majority of people have at least one contact in every 2 years with the health service. If blood pressure is measured at each such contact, the bulk of the problem of detecting those in need of intervention is solved.
TREATMENT :
In essential hypertension, as in diabetes, we cannot treat the cause, because we do not know what it is. Instead, we try to scale down the high blood pressure to acceptable levels. The aim of treatment should
be to obtain a blood pressure below 140/90, and ideally a blood pressure of 120/80. Control of hypertension has been shown to reduce the incidence of stroke and other complications. This is a major reason for identifying and treating asymptomatic hypertension. Care of hypertensives should also involve attention to other risk factors such as smoking and elevated blood cholesterol levels.
PATIENT COMPLIANCE :
The treatment of high blood pressure must normally be life-long and this presents problems of patient compliance, which is defined as “the extent to which patient behaviour (in terms of taking medicines, following diets or executing other lifestyle changes) coincides with clinical prescription”. The compliance rates can be improved through education directed to patients, families and the community.
Intensive research carried out during the past decade, aiming at control of hypertension at the community level, has already provided valuable results. The studies have shown that control of hypertension in a population is feasible, that it can be carried out through the existing system of health services in different countries, and that the control of blood pressure leads to a reduction of complications of high blood pressure – namely stroke, heart failure and renal failure. In some of the projects the incidence of myocardial infarction was also reduced. As a result of these findings some countries have launched nationwide control
programmes in the field of hypertension. .