Presentation is loading. Please wait.

Presentation is loading. Please wait.

Epidemiology and treatment of hypertension Note the first part of this presentation on risk-based assessment of BP treatment has been provided by Professor.

Similar presentations


Presentation on theme: "Epidemiology and treatment of hypertension Note the first part of this presentation on risk-based assessment of BP treatment has been provided by Professor."— Presentation transcript:

1 Epidemiology and treatment of hypertension Note the first part of this presentation on risk-based assessment of BP treatment has been provided by Professor Rod Jackson, Head of Division of Community Health Faculty of Medical & Health Sciences University of Auckland

2 Part 1 n Defining ‘hypertension’ and making decisions based on cardiovascular risk

3 Argument 1. There is no clinically relevant entity that can be defined by a mildly raised blood pressure. 2. A mildly raised blood pressure level is not a major determinant of which patients benefit from blood pressure lowering

4 what is mild hypertension?

5 SBP (mmHg) Systolic blood pressure distribution: Framingham Study participants 35-64 years 74-119120-139140-159160-179180-300 top x%??

6 ??

7 11 16 26 32 28 30 18 17 16 10 ??

8

9 Definitions of mild hypertension & prevalence

10 ?? ≥130/80

11 what is mild hypertension? n it’s the wrong question

12 who benefits from blood pressure lowering?

13 Meta-analysis of RCTs of BP lowering drugs: 15,559 patients, SBP diff 17 mmHg, DBP diff 9 mmHg, follow-up 4.1 years (≥ 60 years) Endpoint Odds ratio (Relative risk red.) Stroke morbidity 35 % Stroke mortality 36 % 0 0.5 1.0 1.5 CHD mortality 25 % CHD morbidity 15 % Insua et al Ann Intern Med 1994;121:355-62

14 Stroke and blood pressure lowering: subgroup analysis from 17 RCTs Trial % Events Relative risk red. group control treatment Some ≥ 110, 6.5 % 4.6 %32 % all ≤ 115 All entry 2.2 % 1.3 %39% DBP < 110 0 0.5 1.0 1.5 MacMahon & Rogers J Vasc Med Biol 1993;4:265-71 Some or all 8.2 % 4.7 %45 % ≥ 115

15 Stroke and blood pressure lowering: subgroup analysis from 17 RCTs Trial % Events Odds ratio (Relative risk red.) group control treatment Older 7.0 % 4.6 %34 % patients Younger 2.3 % 1.3 %43 % patients 0 0.5 1.0 1.5 1º prev. 3.2 % 2.0 %38 % 2º prev. 27.3 % 18.8 %38 % MacMahon & Rogers J Vasc Med Biol 1993;4:265-71

16 Stroke and blood pressure lowering: subgroup analysis from 17 RCTs Trial % Events Odds ratio (Relative risk red.) group control treatment Older 7.0 % 4.6 %34 % patients Younger 2.3 % 1.3 %43 % patients 0 0.5 1.0 1.5 1º prev. 3.2 % 2.0 %38 % 2º prev. 27.3 % 18.8 %38 % MacMahon & Rogers J Vasc Med Biol 1993;4:265-71 1% 2.4% 1.2% 8.5%

17 which patients should be treated? n “individual treatment can only be justified if there is individual benefit” n “only absolute benefits are relevant to patients”

18 PSC Lancet 1995;346:1647-53 (45 prospective studies: 450,000 people 13,000 events)

19 PSC Lancet 1995;346:1647-53

20 SBP 105 ----189 105 ----189 105 ----189 105 ----189 105 ----189 high chol. - + + + + gluc intol. - - + + + cigarettes - - - + + LVH - - - - + CVD risk per 1000 in 8 years Absolute risk of CVD risk in 40 year old men by SBP and other risk factors, Framingham, USA 46 210 326 459 700

21 4567845678 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 4567845678 45678456784567845678 NonsmokerSmokerNonsmokerSmoker WOMEN AGE 70 AGE 50 AGE 40 DiabetesNoDiabetes Ratio of Total Cholesterol:HDL AGE 60

22 4567845678 180/105 160/95 140/85 120/75 180/105 160/95 140/85 120/75 4567845678 NonsmokerSmokerNonsmokerSmoker AGE 70 DiabetesNoDiabetes Ratio of Total Cholesterol:HDL

23 CVD risk & NNTs 5yr CVD risk5 yr NNT* > 30%< 10. 5-10% 40 2.5-5% 85 120 * assumes 33% RRR

24 50 yr old woman BP 160/95 mmHg non smoker TC 240 mg/dl HDLC 62 mg/dl BMI 25 no Hx CVD 60 yr old man BP 148/ 88 mmHg smoker TC 240 mg/dl HDLC 38 mg/dl BMI 25 no Hx CVD is BP lowering therapy indicated ?

25 50 yr old woman BP 160/95 mmHg non smoker TC 240 mg/dl HDLC 62 mg/dl 60 yr old man BP 148/ 88 mmHg smoker TC 240 mg/dl HDLC 38 mg/dl is BP lowering therapy indicated ? 5 yr absolute CVD risk: 4% 5 yr NNT: 72 5 yr absolute CVD risk: 24% 5 yr NNT: 12

26 50/60 yr old woman non smoker TC 240 mmol/L HDLC 60 mmol/L No diabetes SBP mmHg:150160170 5 yr NNT:90 / 5070 / 4260 / 37

27 To treat or not to treat “mild hypertension” “treat risk not blood pressure” “only absolute risks and benefits are relevant to patients” “the payer should choose the threshold”

28 Part 2 Pharmacological considerations in hypertension management Sue Hill and David Henry Discipline of Clinical Pharmacology

29 Factors that influence blood pressure n sympathetic nervous system n total peripheral resistance –mainly arterioles n intravascular volume (renin- angiotensin) –renal excretion n atheroma, thrombosis

30 things that alter vascular resistance n vascular smooth muscle –mediators from sympathetic nerves and vascular endothelium –calcium dependent –contraction due to  intracellular calcium –relaxation due to  calcium entry or  cGMP, cAMP n depends on intact endothelium n complex, interdependent biochemical reactions

31 drugs that will reduce vascular resistance n nitric oxide, nitrates n  - antagonists n  - antagonists n Calcium channel blockers n angiotensin II antagonsists n (lots more)

32 other mechanisms to remember n central control - –methyldopa, ganglion blocking drugs n renal excretion of sodium and water –diuretics, spironolactone

33 drugs we use for hypertension n  - blockers n thiazide diuretics n Calcium channel blockers n angiotensin converting enzyme inhibitors n ( others - alphamethyldopa, reserpine, hydralazine, prazosin )

34 thiazide diuretics n ACTION: increase sodium and water excretion by decreasing reabsorption of sodium and chloride in the distal tubule (later effect on vessels) n EFFECT lowers blood pressure- over several days decreases complications, morbidity and mortality ( good clinical trials) n Side effects: –metabolic effects: diabetes, gout, low Na, K, impotence

35  - adrenoceptor antagonists n ACTION: –effects on heart (  1 ) and smooth muscle (  2 ) via noradrenaline –lowers BP: reduces cardiac output reduces renin release reduces central sympathetic activity effect on pre-synaptic noradrenaline release –nonselective antagonist = propranolol –relatively selective  1 = metoprolol, atenolol –mixed agonist/antagonist - oxprenolol

36  - adrenoceptor antagonists n EFFECT lowers blood pressure - over several days decreases complications, mortality and morbidity (good clinical trials) n SIDE EEFECTS –bronchospasm, fatigue, bad dreams, cold extremities –worsening cardiac failure, heart block –hypoglyacaemia

37 ACE-inhibitors n ACTION –inhibits conversion of angiotensin I to angiotensin II - effects on vasculature in kidney, brain, heart –vasodilator –eg: captopril, enalapril, lisinopril, ramipril n EFFECTS –lower blood pressure- relatively rapidly –effect on mortality, morbidity and complications?? –Reduces mortality in cardiac failure, post-AMI; good clinical trials

38 ACE-inhibitors n SIDE EFFECTS: –cough, rash, taste disturbances –renal failure, neutropenia, proteinuria n COST –relatively expensive

39 Angiotensin II antagonists n losarten, ibersarten, candesarten n actions similar to ACE inhibitors n effects – lower blood pressure- relatively rapidly –effects on clinical outcomes? n Side effects: –rash, cough n cost: expensive

40 calcium antagonists n ACTION: –three classes: verapamil, dihydropyridines, benzothiazepines –block calcium entry into cells by preventing opening of voltage gated calcium channels –act on heart and smooth muscle, depending on type –vasodilator effect (mainly dihydropyridines) –two forms - immediate and slow release n EFFECTS –lower blood pressure - can be rapid –mortality, morbidity, complications??

41 Calcium antagonists n SIDE EFFECTS –flushing, headache, ankle swelling, constipation –heart block, worsening cardiac failure

42 choices n BENEFITS –short-term –long term n RISKS –side-effects –lack of beneficial effect ( unnecessary medication)

43 issues n Preventive versus curative treatment n need for joint decision making n use of drugs with clinical effects versus elegant pharmacologically active molecules n benefits versus risks!!

44 terms n agonist, partial agonist n receptor n antagonist, competitive antagonist n ligand n affinity n mediators n tolerance


Download ppt "Epidemiology and treatment of hypertension Note the first part of this presentation on risk-based assessment of BP treatment has been provided by Professor."

Similar presentations


Ads by Google