EPIDEMIOLOGY OF HYPERTENSION (HT) HYPERTENSION • It is commonest CVD • It is a major RF for CV mortality, CHD, CVA, CHF, and RF • The relationship between BP and risk of CVD events is continuous, consistent, and independent of other RFs. The higher the BP the greater the chance of heart attack, HF, stroke, and kidney diseases. • In EMR it affects about 25% of adult population • About 75% of hypertensive individuals are unaware of being diseased • About 50% of hypertensive patients who knew they are diseased are either not on treatment or taking treatment but not controlled. HYPERTENSION • • • • Definition of hypertension is arbitrary BP follows normal distribution curve BP has a high intra-individual variation CV risk associated with HT is strongly correlated with both SBP and DBP, correlation is higher with SBP Population with HT constituted a risk pyramid: • No. of individuals with mild HT at the base of the pyramid is high, but the RR is small • No. of individuals with sever HT at the tip of the pyramid is small, but the RR is high • Absolute no. of complications attributable to HT is more at base than the tip of the pyramid To achieve community control of HT related CV complications it is important to control mild HT • A 2mm decrease in the entire distribution will decrease mortality from stroke by 6%, CHD by 4% and all causes by 3% • Beginning at 115/75mmHg, CVD risk (IHD and Stroke) doubles for each increment of 20/10mmHg • BP values between 130-139/85-89mmHg are associated with a more than twofold increase in relative risk from CVD as compared with those with BP levels below 120/80 mmHg • DHT predominates before age 50, either alone or in combination with SBP elevation • The prevalence of SHT increases with age and above 50 SHT represents the most common form of HT • DBP is a more potent CV RF than SBP until the age 50, thereafter SBP is more important. CLASSIFICATION OF HT The severity of HT depends on: • BP level • Concomitant CV RFs • End-organ damage For practical reasons, HT can be classified into 1.HT with NO other CV RFs and NO target organ damage 2.HT with other CV RFs 3.HT with evidence of target organ damage 4.HT with other CV RFs AND evidence of other organ damage Classification of HT by BP level: TYPE • • • • • Normotensive Mild HT Subgroup, Borderline HT Mod. And Severe HT Isolated SHT • Borderline SHT SBP (mmHg) DBP (mmHg) <140 140-180 140-160 >180 >140 and or or or and <90 90-105 90-95 >105 <90 140-160 and <90 Classification of HT by Target Organ Damage: • Stage I: No Manifestation • Stage II: At least one of the following: 1.LVH 2.Gen. or Focal narrowing of retinal arteries 3.Microalbuminuria; proteinuria: and /or slight increase in serum creatinin level (1.2-2 mg/dl) 4.U/S or radiology evidence of plaque in aorta, carotid, iliac, or femoral arteries H m g . A n d e x u d a t e s + / p a p i l l o Stage III: Appearance of symptoms or signs • Heart: AP MI HF • Brain: Stroke TIA HT encephalopathy Vascular dementia • Optic fundi Retinal Hmg. And exudates +/papilloedema • Kidney: S.creatinin level > 2 mg/dl RF • Vessels: Dissecting aneurysm Symptomatic occlusive disease Classification of HT by Causes I.Primary (essential) HT II.Secondary HT: • Renal: renal parenchyma dis., Reno vascular dis. , rennin producing tumor • Drugs: OC, Corticosteroids , Liquorices< carbenoxolone, sympathomometics , NSAIDs • Endocrin:Acromegaly, Cushing Syndrome, Primary hyperaldosteronism, Congenital adrenal hyperplasia, Pheochromocytoma, Carcinoid tumors • Coarctation of Aorta and Aoartitis • Pregnancy induced HT RECLASSIFICATION OF BP • New data of lifetime risk of HT and the increase of CV complications associated with levels of BP previously considered to be normal • JNC 7 introduced “ prehypertension” • The aim is to identify those in whom early intervention by adoption of healthy lifestyle could reduce BP, decrease the rate of progression of BP to hypertensive levels with age, or prevent hypertension entirely. JNC6 category SBP/DBP JNC7 category Optimal <120/80 Normal Normal Borderline 120-129/80-84 130-139/85-89 Prehypertensio n Hypertension ≥140/90 Hypertension Stage 1 Stage 2 Stage 3 140-159/90-99 160-179/100-109 ≥180/110 Stage 1 Stage 2 Stage 2 CLASSIFICATION OF BP FOR ADULTS BP classification SBP mmHg <120 DBP mmHg And <80 PREHYPERTE NSION STAGE 1 HT 120-139 Or 80-89 140-159 Or 90-99 STAGE 2 HT ≥160 Or ≥100 NORMAL • Prehypertension is not a disease category. They are not intended to have drug therapy, but should be advised to practice lifestyle modification to reduce risk of developing HT • Individuals with prehypertension who also have DM or kidney diseases should be considered candidates for appropriate drug therapy if a trial of lifestyle modification fails to reduce their BP to 130/80mmHg or less. • This classification does not classify HT patients by the presence or absence of RFs or target organ damage in order to make different treatment recommendations, should either or both be present. • All patients with stage 1 or 2 should be treated and the goal is to reduce BP in HT patients with no other compelling conditions <140/90 • The goal for individuals with prehypertension with no compelling conditions is to lower BP to normal levels with lifestyle changes, and prevent the progressive rise in BP using the recommended lifestyle modifications. Factors influencing BP level: – Age: appositive association between BP level and age in most populations of different geographical, cultural, and SE characteristics. The rise in SBP continue throughout life in contrast to DBP which rises until the age 50, tends to level off over the next decade, and may remain the same or fall later in life. – Sex: early in life, there is no difference between males and females in BP level, but after puberty males tend to have higher BP level than females. After menopause the difference gets narrower. Factors influencing BP level: – Ethnicity: Blacks have higher BP level than others – SE status: in post-transitional populations – inverse relation In pre and transitional populations – positive association Risk Factors of HT 1.Hereditary factors : positive family history 2.Genetic factors: certain genes as ACE gene 3.Early life exposure to certain events: as LBW 4.Certain childhood predictors: as BP response to exercise, weight gain, LV mass… Risk Factors of HT 5.Body weight: overweight individual has 2-6 times higher risk having HT compared to a normal weight individual. 6.Central Obesity and Metabolic Syndrome: high waist/hip ratio is positively associated with HT 7.Nutritional factors: positive association between Nacl intake and HT, negative association between potassium intake and HT, and no relation with other nutrients. Risk Factors of HT 8.Alcohol intake : causes acute and chronic increase in BP level 9.Physical Inactivity : Sedentary unfit individual has 20-50% excess risk to have HT 10.Heart rate : Ht patients have HR than normotensive individuals 11.Psychological factors: acute mental stress causes increase in BP level 12.Environmental factors: noise, air pollution Organ Damage Associated With HT • The incidence depends on level of other RFs as DM, HCH, Smoking… 1. LVH: • Powerful predictor of CV complications • Higher risk with strain pattern than with voltage pattern • Best diagnosed by Echo. • Reversible by anti-HT , and causes improvement of diastolic function with no impairment of systolic function 2.Atherosclerosis: Higher in presence of other RFs 3.CHF : • Progressive LV dilatation • LVH+ Coronary Atherosclerosis mark the development of CHF • Anti-HT can decrease incidence of CHF by 50% 4.Stroke: • HT is the most important and the most modifiable Rf of all types of stroke • 5-6 mmHg reduction in DBP can decrease incidence of stroke by 40% 5.Carotid Stenosis • Frequent cause of stroke • Ulcerated plaques can be a source of emboli causing TIA 6.Kidney: • Severe accelerated HT causes fibrinoid necrosis of small blood vessels leading to renal insufficiency • Renal damage in HT is heralded by proteinuria • Microalbuminurea and proteinurea are • independent RF of all CV mortality • Effective BP reduction can decrease risk of proteinurea Prevention of HT • Community Approach Primary prevention of HT in the whole population Prevention of HT • High risk Approach ( individual case management) Identification of individuals with high BP who are at increased of complications The two approaches are complementary Needs of HT control Strategy 1.Data collection: prevalence of HT, RFs of HT, and other CVDs 2.Early Detection: in the health setting and increased self referral through increased public awareness 3.Health Care Services: responding to the needs of HT patients, and providing adequate diagnostic and treatment facilities Needs of HT control Strategy 4.Coordination of the government and NGOs concerned in primary prevention of HT and integrate it NCDs Prevention Program, concentrating on life style measures 5.Community Participation: health education 6.Medical Audit: to monitor the process and quality of care to patients with HT Community Approach Aim: Primary Prevention of HT through: 1.Elimination of modifiable RFs 2.Promotion of protective factors maintaining reasonable BP 3.Reduction of risks of complications by altering the norms and behavior of population It is useful to: – Avoid risky life-style that increase BP – Adoption of healthy life-style – Encourage industrial and agricultural activities to provide healthier food Goals: • Increase population awareness that HT is a major PH problem • Help in detection of HT patients or those at risk • Advocate life –style that eliminate controllable RFs Components: 1. Public Education: • Nature, causes, complications, prevalence and treatable nature of HT. • Life –style measures for prevention, management, and contributory role of other CV RFs. Components: 2. Professional Education: • Training in detection, management, and prevention of HT. • Adoption of advocacy role in the community to adopt healthy life-style. Components: • 3. Patient Education: Components: • • • • The need for effective management Benefits of life-style changes The need to adhere to health care advice Regular monitoring and periodic visits Population approach is highly effective in decreasing HT and its complications in the community, but it offers little direct individual effect, making it of less motivation to people and physicians. Life style modification at population level requires: 1.Inter-sectoral collaboration 2.Multidisciplinary approach 3.Community involvement and participation particularly through NGOs Individual Approach Aim: Prevention of complications among HT patients Components: • Identification of HT patients at risk of complications • Effective management of HT through life-style modification with or without pharmacologic intervention. This approach is associated with high motivation for patients and physicians, but it is costly. The two approaches are complementary to each other Lifestyle measures for prevention of HT In the whole population (primary prevention) they help in: • Decrease risk of development of HT • Decrease risk of development of other lifestyle related disorders (DM, CHDs,) Lifestyle measures for prevention of HT In individual patient, they help in: • Decrease BP • Avoid or decrease need for anti-HT treatment • Control associated RFs FOYR life-style measures proved effective in clinical trials: 1.Weight Reduction • Decreases BP in HT patients with >10% overweight • Decreases insulin resistance • Improves lipid profile Obese patients with mild or borderline HT should try weight reduction for 3-6 months before starting anti-HT treatment 2.Reduction of alcohol intake: • Decreases SBP/DBP by 4.8/3.3 mmHg • When combined with 10 Kg weight loss , BP will decrease by 10.2/7.5 mmHg 3.Increased physical activity • Effective for prevention and treatment of HT • Dynamic , isotonic exercises ( walking) is more effective than static , isometric exercises ( weight lifting) • Brisk walking for 30-60 minutes /day for 5 times / week is better than strenuous exercises. 4.Reduction of Sodium intake • Recommended intake is < 6 gm /day • Elderly people and blacks demonstrate more sensitivity to sodium restriction Life style measures to control other CV RF 1.Tobacco smoking • Smoker hypertensive has 2-3 folds excess risk of stroke and CHD. • Cessation of smoking is the most effective single step to decrease CV risk among hypertensive. Life style measures to control other CV RF 2.Dyslipidemia Increased physical activity is most appropriate in HT patients with dyslipidemia Life style measures to control other CV RF 3.Diabetes Mellitus Regular exercise, weight reduction, and low fat high fiber diet can improve insulin sensitivity, and decrease contribution of insulin resistance to high BP.