Hypertension - The "Silent Killer"

Hypertension (high blood pressure) is one of the most preventable causes of premature morbidity and mortality world-wide.

Hypertension is known as the “Silent Killer”. By 2025, the number of patients diagnosed with hypertension is expected to be 1.56 billion.(3)Hypertension is responsible for >7 million deaths annually (4)of the leading risk factors for cardiovascular disease mortality.(5)The disease is defined as systolic blood pressure (SBP) of 140 mmHg or diastolic blood pressure (DBP) =90 mmHg, or any persons being currently prescribed antihypertensive medicine for the purpose of managing hypertension.(1,2,6)In addition, hypertension is defined as blood pressure readings elevated on at least two occasions with or without provocation.(1)Hypertension is divided into two main categories: essential/primary hypertension and secondary hypertension. (7,8) Lack of identifiable causative factors for elevated blood pressure is known as essential or primary hypertension, making up ~90%–95% of all hypertensive cases. Secondary hypertension, for which there is an identifiable cause affects 5%–10% of US adults who are diagnosed with hypertension.

Blood pressure is normally distributed in the population and there is no natural cut-point above which “hypertension” definitively exists and below which, it does not. Epidemiological studies demonstrate that the aforementioned disease risk associated with blood pressure is a continuous relationship and above blood pressures of 115/70mmHg, the risk of cardiovascular events doubles for every 20/10mmHg rise in blood pressure. The threshold blood pressure determining the presence of hypertension is defined as the level of blood pressure above which treatment has been shown to reduce the development or progression of disease. Primary hypertension was previously termed “essential hypertension” because of a long-standing view that high blood pressure was sometimes “essential” to perfuse diseased and sclerotic arteries. It is now recognised that the diseased and sclerotic arteries were most often the consequence of the hypertension and thus the term “essential hypertension” is redundant and the “primary hypertension” is preferred.

Primary hypertension refers to the majority of people with sustained high blood pressure (approximately 90%) encountered in clinical practice, for which there is no obvious, identifiable cause. The remaining 10% are termed “secondary hypertension” for which specific causes for the blood pressure elevation can be determined.