EPIDEMIOLOGY AND PREVENTION OF HYPERTENSION DR.MAHDI QADI MARCH 2005

1. EPIDEMIOLOGY ANDPREVENTION OFHYPERTENSIONDR.MAHDI QADI MARCH 2005

2. INTRODUCTION • IMPORTANCE: • MAJOR RISK FACTOR FOR • STROKE • CHD • RENAL FAILURE • PERIPHERAL ARTERIAL DISEASE • OTHERS • HEART FAULURE ,RETINAL ARTERY OR VEIN THROMBOSIS • COST AND BURDEN OF TREATMENT • THE BIG BENEFIT OF ITS CONTROL • WHO HYPERTENSION COMMITTIES VERY HIGH MORBIDITY AND MORTALITY 1

3. INTRODUCTION • DEFINITION : • GENERAL DEFINITION DIASTOLIC > = 90 SYSTOLIC > = 140 FOR 3TIMES (4 WEEKS BETWEEN EACH READINGS) • IT IS ARBITRARY • RISK OF MORBIDITY AND MORTALITYIS GENERALLY CONINUOUSLY CORRELATED WITH LEVEL OFBLOOD PRESSUREEVEN THE LEVEL CONSIDERD AS NORMAL • EVEN SINGLE HIGH BLOOD PRESSURE STILL SHOW SOME INCREASE RISK • DIFFERANCE WITH AGE 2

4. INTODUCTION • PERCENTILES & TRACKING IN CHILDREN • 95% OF HYPERTENSION (HTN) IS DUE TO ESSENTIAL HTN • WHY EPIDEMIOLOGY AND RISK FACTORS OF DISEASES ARE IMPORTANT ? 3

5. CLASSIFICATION(18y & older): • CATEGORY SYSTOLIC DIASTOLIC Normal <120 <80 pre-Hypertention 120--139 80--89 Hypertention Stage 1 (mild) 140--159 90--99 Stage 2 160--179 100--109 • The seventh report of the joint national committee on detection, evaluation and treatment of high blood pressure,usa 2003. 4

7. DESCRIPTIVE EPIDEMIOLOGY • INCIDENCE & PREVELANCE: • IN USA PREVELANCE AT CUT POINT 90 DIASTOLIC = 25.3% INCIDENCE = 3% / YEAR • IN KSA …. • HIGH RISK GROUPS: • AGE INCREASE WITH AGE • RACE MORE IN BLACKS IN SOME COUNTRIES • SES MORE IN LOW SES 5

8. ETIOLOGICAL AND RISK FACTORS - EXACT ETIOLOGY STILL CONSIDERD UNKOWN - • 1- Genetics and family history • .Monozygotic twins • 1st degree relatives • Hpt tends to run in families • 2- High salt intake • 7-8 gm / day • The most important environmental factor • Retention of na   plasma volume htn • Noticed in cross population and clinical observations 6

9. ETIOLOGICAL AND RISK FACTORS 3- Obesity • positive relation had been seen in cross sectional and longitudenal studies • bp when obese people lose wt 4- Alcohol intake • positive relation 5- Physical inactivity 7

10. ETIOLOGICAL AND RISK FACTORS 6- Stress • Effect of acute stress in raizing the BP is well known • Effect of chronic stress in causing HTN is postulated & noticed but difficult to test it well • HPT is more in industrial and urban areas • Type a personality 7- Diabetes and high blood glucose level • HTN is more prevelant in diabetics & persons with IGT • Hyperinsulinemia in type 2 DMHTN • DM nephropathyHTN 8

11. ETIOLOGICAL AND RISK FACTORS 8- Other dietary factors • Potassium • HTN is associated with low K intake • Animal fat & fibers • Evidences suggest that diet low in animal fats(saturated fat) & high in fibers has an antihypertensive effects • Low CA & MG • Hyper tensive effect of low intake (controversy) • Caffeine • Some put high intake as risk factor but no consistant data 9

12. ETIOLOGICAL AND RISK FACTORS 9- Environmental pollutant • The strongest evidence is regarding CADMIUM but still need further proof • LEAD is also claimed 10- Others • Persons with high normal, labile & border line BP • Childeren with persistence of relatively high BP values • NSAID • Polycythemia 10

14. PREVENTION • Low prevelance in some countries ie HTN is potentially preventable • WHO recommend the following approaches: • Primary prevention A- Population strategy B- High risk strategy • Secondary prevention • Not to forget preventive actions in children 11

15. Primary PREVENTION * Why primary Prevention for HTN still important although secondary is effective ! A- Population strategy 1- nutrition • Low salt diet not > 5 gm / day • Moderate fat • Avoidance of excessive caloric intake • Good balance diet in general • Avoidance of alcohol 2- WT reduction 3- Exercise promotion 12

16. Primary PREVENTION 4- Behavioral changes •  Stress • Modification of personal life style • spiritual health 5- Educating the public about risk factors and motivating them for primary prevention 13

18. Primary PREVENTION B- High risk strategy 1- Detecting the high risk subjects (through good phc system &periodic medical examination) 2- Applyingthe primary prevention measures on the high risk subjects 3- Follow up of the high risk subjects 14

20. Secondaryprevention A- Early case detection • HTN is a suitable disease for screening • Mass screening is expensive and need to be linked to follow up to be beneficial • Screening in the PHC services • When people come for regestration and consultation • Simple feasible and continuous • Yield is good in age 35----75 ( but advised to be done from age 18- and even earlier-) • Concentrate on high risk subjects 15

21. Secondaryprevention B- Proper treatment • Aim BP to be < 140 / 90 • Importance of treating mild HTN • Should be comprehensive care ( ie attention to other problems & risk factors ) • Non pharmacological & pharmacological • Patiet compliance • The good yeild of proper treatment ( in complications namely stroke,heart failure and renal failure ) 16

22. ADVISED REFERENCES • 1- R.Brownson. Chronic diseases epidemiology& control. • 2- Last. Public health &preventive medicine. • 3- Park. Textbook of preventive & social medicine