**4.1 Definitions challenges, and first drug choice**

Up from what level a blood pressure is considered as high or as hypertension has been a constant discussion over time. Since the relationship between blood pressure and adverse health effects displays a non-linear but continuous relationship (John KJ Li 2000), any classification of people into dichotomous categories ('normotensive' and 'hypertensive') as well as other blood pressure staging are arbitrary (Mancia and others 2007). Nevertheless, clinicians and other health care workers often must make essentially dichotomous decisions (Birkett 1997) (e.g. whether or not to start pharmacological treatment for elevated blood pressure). The basis for classifying people into 'hypertensive' and 'normotensive' groups is encouraged by a consideration of 'excess risk' or by proven treatment benefit in clinical trials (Birkett 1997) for a certain level of blood pressure.

4.2 (33,461/798,390)

12.3 (60,128/487,692)

26.3 (102,484/389,053)

45.8 (162,533/355,094)

61.2 (333,947/545,786)

26.9 (692,553/2,576,015)

**[a]** Age range for USA prevalence starts from 18 years, for England are from 16 years and for sub-Saharan Africa are from 15 years; **[1]** Results from a meta-analysis on the population-based

studies(Twagirumukiza and others 2011); **[2]** Results from the Health Improvement Network (THIN) database & Health Survey for England (HSE)(MacDonald and Morant 2008); **[3]** NHANES III continuous(Fields and others 2004); **[4]** WHO standard population adjusted prevalence; **NS:** Not

Table 1. Comparison between sub-Saharan Africa pooled data and developed countries

Up from what level a blood pressure is considered as high or as hypertension has been a constant discussion over time. Since the relationship between blood pressure and adverse health effects displays a non-linear but continuous relationship (John KJ Li 2000), any classification of people into dichotomous categories ('normotensive' and 'hypertensive') as well as other blood pressure staging are arbitrary (Mancia and others 2007). Nevertheless, clinicians and other health care workers often must make essentially dichotomous decisions (Birkett 1997) (e.g. whether or not to start pharmacological treatment for elevated blood pressure). The basis for classifying people into 'hypertensive' and 'normotensive' groups is encouraged by a consideration of 'excess risk' or by proven treatment benefit in clinical

**Statistical comparison test** 

**sub-Saharan Africa vs England** 

<0.001 <0.001\* <0.001\*

<0.001 <0.001\* NS

<0.001 <0.001\* NS

0.045 0.004 NS

<0.001 NS <0.001

<0.001 <0.001 <0.001

**sub-Saharan Africa vs USA** 

**p-value** 

**all** 

6.0 (178/2,971)

16.0 (135/846)

31.0 (242/781)

48.0 (312/650)

71.4 (849/1,189)

26.7 (1,716/6,437)

22.3 18.4 21.6 <0.001 <0.001\* NS

**(number of diagnosed hypertensive people/sample size)** 

**Age-range[a] [1]sub-Saharan Africa [2] England [3] USA Within** 

**Crude hypertension prevalence in %** 

(19,366,486/281,419,841)

(12,788,663/74,689,253)

(14,195,235/49,276,086)

(13,886,165/31,526,626)

(14,470,484/24,074,117)

(74,707,034/460,985,923)

statistically significant \*sub-Saharan Africa is statistically higher.

**4.1 Definitions challenges, and first drug choice** 

trials (Birkett 1997) for a certain level of blood pressure.

**4. Management of hypertension in primary health care** 

15-34 6.9

35-44 17.1

45-54 28.8

55-64 44.0

≥65 60.1

Overall 16.2

Prevalence standardized for WHO standard population **[4]**

surveys.

The definition of hypertension is then based on the potential of blood pressure to become a risk for cardiovascular events (Khosla and Black 2006). But this evaluation of potential risk has been improving in time and cut-offs have been lowered progressively. Previously, hypertension started at a cut-off SBP/DBP value of 160/95 mmHg, whereas the current standard is 140/90 mmHg. The current definition of hypertension which is unanimously agreed on by USA Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC7)(Chobanian and others 2003), European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC)(Mancia and others 2007) and World Health Organization (WHO)(Chalmers and others 1999) is : **SBP ≥ 140mmHg and/or DBP ≥ 90mmHg and/or being on blood pressure lowering medication**(Chalmers and others 1999; Chobanian and others 2003; Mancia and others 2007). These cut-off values are even lower in high risk population (diabetes or renal failure). Different thresholds have been given for different types of measurements (Table 2).


Table 2. Different Blood pressure thresholds (mmHg)(Mancia and others 2007)

In daily practice, the blood pressure has also been splitted up into grades to help management. In this chapter, the most recent (2007) classification (Mancia and others 2007) will be used as a reference.


JNC-7: the Seventh report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure (JNC-7)(Chobanian and others 2003). ESH/ESC: the European Society of Hypertension – European Society of Cardiology(Mancia and others 2007). WHO/ISH: the World Health Organization/ International Society of Hypertension(Whitworth 2003). Note that hypertension is defined as SBP/DBP of 140/90 mmHg according to the three recommendations(Chemla 2006).When a patient's systolic and diastolic blood pressure fall into different categories, the higher category should apply.

Table 3. Recent classifications and staging of Systolic (SBP) / Diastolic (DBP) Blood Pressure levels

The Use of Antihypertensive Medicines in Primary Health Care Settings 137

It has been proposed (Mancia and others 2007) that the management of hypertension should be based on two criteria, i.e. (1) the level of systolic and diastolic blood pressure, and (2) the level of added cardiovascular risk (List 1). Thus, the management of hypertension has been shifted from viewing and treating it as an isolated element to a more comprehensive approach of cardiovascular risk stratification that takes into account other cardiovascular risk factors like cholesterol, smoking, diabetes and metabolic syndrome (MS). In addition, subclinical organ damage (List 2) is considered as higher added risk showing that risk

The cardiovascular risk stratification table (Table 4) is obtained by combination of presence of risk factors, target organ damage and diabetes and the levels of systolic and diastolic

We have to keep in mind that many other risk tables have been developed as well. Hippisley-Cox and colleagues have developed and validated the second version of the QRISK cardiovascular disease risk algorithm (QRISK2), an attempt to more accurately estimate cardiovascular risk in patients from different ethnic groups in England and Wales(Christiaens 2008). The SCORE tables used the same risk factors to calculate corrected European cardiovascular mortality (Christiaens 2008). More recently the ASSIGN (Christiaens 2008) and now the QRISK tables (Christiaens 2008) tried to incorporate some

All attempts to make risk tables more accurate, as done by Hippisley-Cox and colleagues in the QRISK2 algorithm (Christiaens 2008) should be welcomed. However, this is not the key problem. We have to fundamentally rethink how to use risk tables when making treatment decisions in practice, taking into consideration the prescribing in healthy older people and

• Electrocardiographic LVH (Sokolow-Lyon >38 mm; Cornell >2440 mm\*ms) or:



• Echocardiographic LVH(LVMI M≥125 g/m2, W ≥110 g/m2)

other known risk factors, especially deprivation and family history.

factors led to organ damage.

the correct use of drugs.

(<60 ml/min)

mg/g creatinine



List 2. Sub-Clinical Organ Damage (OD)


• Men (M): 115–133 µmol/l (1.3–1.5 mg/dl); • Women (W): 107–124 µmol/l (1.2–1.4 mg/dl)

\*Adapted from "2007 ESC/ESH Recommendations" (Mancia and others 2007)

blood pressure.

In some patients, medical office blood pressure is persistently elevated while ambulatory or home blood pressure, are within their normal range. This condition is widely known as '*white coat hypertension*' (Mancia and others 2007). Inversely the hypertension found with ambulatory blood pressure measurement but not in clinic is known as "*masked hypertension*" (Papadopoulos and Makris 2007).
