Transcript Angina, Myocardial Infarction and Claudication

Dietetic Guidelines for
Secondary Prevention of
Cardiovascular Disease
Alison Mead
Chief Dietitian
On behalf of
UK Heart Health and Thoracic Dietitian’s
Specialist Group of the BDA
UK HEART HEALTH GROUP
• UK Heart Health & Thoracic Specialist Group of
British Dietetic Association
– Approx 70 members
• Dietetic Guidelines: Diet in Secondary Prevention
of CVD
– Published August 2001
– 1st update August 2004
– 2nd update October 2006 In press
Previous Guideline
recommendations
1. Increased omega 3 fat intake
2. Reduction in saturated fat with total or
partial replacement by unsaturated fat
3. Mediterranean dietary advice for those
that have suffered an MI
Literature Search
• Cochrane, DARE, MEDLINE, EMBASE to Jan 05
• Identify all Systematic Reviews of Randomised
Controlled Trials for diet and secondary prevention
of CVD with the following outcomes:
– Further CVD (MI, angina, stroke, PVD, CABG, PTCA)
– Death
– CV risk factors (lipids, weight, central obesity, BP, DM,
raised homocysteine)
Inclusion
• Reviews were included if:
– Outcome data from RCTs could be separated from
other data
– Intervention was some sort of dietary advice
– At least one RCT was in people with CVD and no
heterogeneity to those without
– Outcomes
• Further CVD (MI, angina, stroke, PVD, CABG, PTCA)
• Death
• CV risk factors (lipids, weight, central obesity, BP, DM,
raised homocysteine)
GRADING THE EVIDENCE:
• Evidence was graded on the quality
of evidence
– Excellent = 1, evidence from
RCTs or SRs
1A
• It was also graded on importance of
outcomes
– A= on morbidity or mortality
– B= on a risk factor
Quality
Assessment
GUIDELINES:
summary based on evidence 1A
• There are systematic reviews on the effects of the
following dietary factors on cardiovascular disease or
death:
Omega 3 Fats
Mediterranean diet
Low or modified fat
Antioxidant vitamin supps
Garlic supplements
Gingko biloba
Low GI diets
Homocysteine lowering
therapies
Multifactorial interventions
GUIDELINES:
summary based on evidence 1B
• There are SR for dietary factors effect
on cardiovascular risk factors:
– Omega 3 Fats
– Low fat/ 600kcal deficit
– Fat replacement
– Low GI diets
– Garlic supplements
– Homocysteine lowering therapies
– Multifactor interventions
Omega-3 fat and mortality
 Eating n-3 fatty acids or taking fish oil supplements
(1g/d) both reduce mortality in patients that have had
an MI (Bucher et al. 2002)
 3 portions of oily fish/ week
 or 1g/d from supplement (Docosahexanoate acid/
Eicosapentaenoic acid)
 Not clear whether this is quantity of n-3 fatty acids are
beneficial in CVD patients that have not suffered an MI.
(Hooper et al 2004, Wang et al 2004)
Fig 3 Effect of omega 3 fatty acids on cardiovascular events.
Hooper, L. et al. BMJ
2006;332:752-760
Copyright ©2006 BMJ Publishing Group Ltd.
Omega-3 fat and mortality
In diabetics fish oil does not worsen glycaemic control or
LDL levels. (Farmer 2002)
Plant Based:
Evidence for effectiveness of plant-based omega-3 fats (eg
rapeseed oil/canola flax or linseed oil) is unclear.
But, the effectiveness of the Mediterranean diet in the Lyon
study, which gave out rapeseed margarine, means it is
probably appropriate to suggest vegetarian sources of
omega-3 fats for those who cannot take fish or fish
oil.
Mediterranean diet: potentially protective
post MI
More omega-3 fats, fruit &
vegetables, less saturated
fat & partial replacement by
rapeseed or olive oil &
100
Diet
Control
80
more emphasis on fresh
(not ready prepared) foods
(Evidence presented in a SR, but
based on only 1 RCT, so not
strong)
5
Years
De Lorgeril et al Circulation 1999;99:779
Reduction in Saturated Fat
• A reduced or modified fat intake, followed for
at least 2 years, results in a small reduction in
risk of cardiovascular events
– Up to 2 yrs - 96 events for every 100 people
– > 2 yrs – 76 events for every 100 people
Antioxidants
• Epidemiological data was promising
• RCTs showed no benefit
• Vitamin E:
– No effect on all cause mortality (RR 0.96, CI 0.84
to 1.1) or CVD risk (RR 0.97 CI 0.8 to 1.19) Skekelle
2004
– High doses (>400IU/d) increase risk of mortality
(RR 1.04 CI 1.01 to 1.07) Miller 2005
• Beta- carotene
– Increase risk of death (OR 1.07 CI 1.02 to 1.11)
and CVD death (OR 1.1 CI 1.03 to 1.17) Vivekananthan
2003
Ginko biloba, multi-factorial
Gingko biloba extract appears
to increase pain-free walking
distance modestly, in people
with intermittent claudication
(Pittler 2000)
Multifactorial interventions
appear to be more effective
than single dietary interventions
at reducing mortality and
morbidity in people with CVD
(Ketola 2000)
Low GI, Homocysteine, Garlic
• No evidence as to whether low GI diets effect
CHD mortality or events (Kelly 2004)
• No evidence as to whether plasma homocysteine
lowering therapies (folate, Vit B12, B6) affect PAD
progression (Hansrani 2002)
– Two recent RCTs show no effect on events
NORVIT Trial NEJM 2006, HOPE 2 NEJM 2006
• No evidence of any beneficial effect of garlic
supplements in people with peripheral arterial
occlusive disease (Jepson, Kleijnen & Leng 1999)
Summary evidence level 1B
Diet and Risk Factors
All dietary advice to reduce
lipids etc is supplementary to
cardioprotective diet.
Lipids
Lipid Reduction - Total Cholesterol 3-6%
• Statins more effective
Modified fat intake, including fish oils
Low GI diet (not conclusive)
Garlic (not conclusive)
Weight Loss
Stanol Esters & Plant Sterols (not yet published)
Mono (Olive, Rapeseed)
or
Poly (Sunflower, Walnut, Sesame)?
•
•
•
•
Unclear
Reduction in Total and LDL
High doses of PUFA may reduce HDL
Mediterranean theory
Fish Oils – high doses reduces
TG but increase total and LDL
Lipids
Lipid Reduction - Total Cholesterol 3-6%
• Statins more effective
Modified fat intake, including fish oils
Low GI diet (not conclusive)
Garlic (not conclusive)
Weight Loss (primary care)
Stanol Esters & Plant Sterols (not published)
Hypertension
Independent Risk
Factor
Decrease 35mmHg SBP reduces
CHD risk by 10%
and stroke by 15%
DASH Trial
Hypertension SRs
• Omega 3 fats
– No effect on blood pressure
(Hooper 2004, Morris, Sacks
& Rosner 1993)
– Small reduction in DBP in those with
intermittent claudication (caution, small
poor studies)
• All other SRs are from primary
prevention so not included in guidelines
(potassium, calcium, salt, weight)
Dietary Factors that affect
Hypertension in primary
prevention
• Salt
• Weight Reduction
• Alcohol
• Potassium
• Calcium
• Dairy Peptides (Isoleucine-Proline-Proline and ValineProline-Proline)
Homocysteine, Weight Loss
Raised homocysteine levels can be reduced
by supplementation with folic acid, alone or
with vitamin B6 and B12
No SR to show whether this effect events
Weight Loss: Low fat & 600kcal deficit
resulted in 4.2kg loss more than control
Blood Glucose, HbA1c, DM
diagnosis
• No secondary prevention reviews
Limitations
• Lack of trials
– Alcohol
• Only SRs of RCTs
• Patients that participate
Summary
• Main dietary recommendations that save lives are:
•  saturated fats & total/partially replace with
unsaturated fats (rapeseed or olive oil)
•  omega-3 fat intake, the amount depends on
diagnosis.
• Follow a Mediterranean diet (increase omega 3 fat,
fruit and vegetables and fresh foods, reduction in
saturated fat and processed foods)
• Antioxidant supplements not effective