Lecture 21: Cardiovascular Risk Assessment

Question 1

what is relative risk?

Answer 1

relative risk is the ratio of the probability of an event occuring in an exposed group to the probability of the event occuring in a comparison, non-exposed group

Question 2

what is absolute risk?

Answer 2

absolute risk of a disease is an individual’s risk of developing the disease over a specific time period.

absolute risk can be expressed as a probability in different ways. e.g. a 1 in 10 risk of developing a disease in the next 5 years can also be saif to be a 10% risk

Question 3

what is the framingham risk score?

Answer 3

the framingham study looked at different risk factors and decided which were important enough to include and what levels of risk factors were relevent to CV risks.

for example, total cholesterol is important. has ‘risk points’ from -3 to +3 for men and -2 to +3 for women. higher risk point = higher risk

they did the same for systolic BP, HDL cholesterol and whether or not you have diabetes or are a smoker.

you end up with several points which translates into absolute risk.

depends on the number the risk is interpreted as below average risk, average risk, moderately above average risk, high risk categories for different age groups.

Question 4

what does absolute risk depend on?

Answer 4

multiple different factors

Question 5

how does aboslute risk depend on multiple risk factors?

Answer 5

increase the level of one risk factor from the reference one at a time.

this resulted in an increased risk but there is a graded linear associated with systolic BP

Question 6

how do you estimate CVD risk?

Answer 6

• risk prediction charts/’equations’
• some predict risk of a CVD event over years, some over 10 years
• many based on data from the framingham heart study

Question 7

what guidelines does NZ use?

Answer 7

• uses data from the framingham heart study
• some adjustments for different ethnicities

use risk factors to predict CVD risk in the next 5 years:

• blood pressure
• cholesterol
• age
• diabetes status
• smoking status
• sex

Question 8

what is involved in the NZ Cardiovascular disease risk assessment?

Answer 8

• 5 year cardiovascular disease risk
• based on NZ cohort data from PREDICT study
• 400,728 patients in NZ GP database aged: 45-74 years (men) and 55-74 years (women), from 30/40 years for Maori, pacific and south-asian people

recommendations:

• evidence based
• consistent with other NZ and international guidelines

Question 9

when do you start risk assessments for men and women without known risk factors?

Answer 9

men: 45 years
women: 55 years

Question 10

when do you start risk assessments for maori, pacific and south-asian men and women ?

Answer 10

men: 35 years
women: 45 years

Question 11

when do you start risk assessments for men and women with family history risk factors? what are the family history risk factors?

Answer 11

men: 35 years
women: 45 years

• diabetes in first-degree relative
• hospitalisation for or death from heart attack or stroke in first degree relative before afe of 50 years
• fimilar cholesterolaemia

Question 12

when do you start risk assessments for men and women with personal history risk factors? what are the personal history risk factors?

Answer 12

men: 35 years
women: 45 years

• people who smoke
• gestational diabetes
• HbA1C 41-49mmol/mol
• BMI ≥30 or truncal obesity
• atrial fibrillation

Question 13

when do you start risk assessments for men and women with diabetes?

Answer 13

from the time of diagnosis

Question 14

when do you start risk assessments for men and women with severe mental illness?

Answer 14

men and women: from 25 years

• People with severe mental health illness are at risk mainly due to the medications or are more prone to smoking.

Question 15

what are the variables of CVD?

Answer 15

• age
• gender
• ethnicity
• NZ index of deprivation
• family history of premature CVD or T2DM
• past history CVD/familial hypercholesterolemia
• history of diabetes (duration + renal function)
• smoking status
• HbA1C
• blood pressure
• non-fasting lipids
• eGFR (renal function)
• BMI
• medications

Question 16

what is the shared treatment decision if someone has <5 percent CVD risk?

Answer 16

Lifestyle:
- lifestyle advice (diet, weight management, physical activity, smoking cessation)

Drug Therapy:
- evidence indicated medication menagement has limited benefit

Follow-up:
- for risk level - for risk level 3-5 percent, repeat risk assessment at 5 years

Question 17

what is the shared treatment decision if someone has 5-15 percent CVD risk?

Answer 17

Lifestyle:
- lifestyle advice (diet, weight management, physical activity, smoking cessation)

Drug Therapy:
- discuss the magnitude of the benefits of statins or blood pressure lowering with the patient, based on the evidence that the higher the risk for the patient, the more likely they are to benefit

Follow-up:

• for risk level 5-9 percent, repeat risk assessment at 5 years
• for risk level 10-14 percent, repeat risk assessment at 2 years

Question 18

what is the shared treatment decision if someone has >15 percent CVD risk?

Answer 18

Lifestyle:
- lifestyle advice for diet, weight management, physical activity, smoking cessation

Drug Therapy:
- strong evidence supports using statins and blood pressure lowering to prevent CVD events and deaths

Follow-up:

• review annually
• repeat risk assessment annually

Question 19

what is the shared treatment decision if there is estabilished CVD?

Answer 19

Lifestyle:
- lifestyle advice for diet, weight management, physical exercise and smoking cessation

Drug therapy:
- strong evidence supports pharmacotherapy for modifiable risk factors, and antiplatelet therapy for secondary prevention

Follow-up:
- review annually

Question 20

what are the targets for lipids?

Answer 20

• drug treatment if TC/HDL ratio ≥ 8 regardless of CVD risk
• if CVD risk ≥15%, target LDL below 1.8mmol/L

Question 21

what are the targets for blood pressure?

Answer 21

• drug treatment if persistent BP of 160mmHg systolic and/or 100mmHg diastolic (office) or more regardless of CVD risk
• target below 130/80mmHg (office) (caution in older people)

Question 22

what are the targets for diabetes?

Answer 22

HbA1C 50-55mmol/mol for younger and fitter patients, or 55-64 mmol/mol for older co-morbid and frail patients

Question 23

what is clinical judgement? when should it be used?

Answer 23

there is no evidence or guidelines for people over 75 years so clinical judgment should be used.

clinical judgement use for:

• over 74 years
• those with serious mental illness
• morbidly obese
• those with chronic kidney disease
• taking medicine for HIV
• autoimmune and/or systemic inflammatory disorders

Question 24

what is the strength of risk scoring?

Answer 24

• allows decisions about intervening to be made in a targetted way which makes the best of of resources available to reduce CVD risk
• alternative approaches focus on a single risk factor which labels a large proportion of the population as high risk, which is mostly incorrect
• risk scoring focuses on reducing an individuals overall risk of disease rather than treatment of individual risk factors. it allows for the interventions to match the degree of the total risk.

Question 25

what are some issues with cardiovascular risk assessment?

Answer 25

• 15-20% of patients who develop CVD don’t display the traditional risk factors, but would be labelled as low risk by the prediction algorithms
• there is increasing evidence that atherosclerosis develops in childhood and is associated with the same CVD risk factors. But intervening in adulthood might be too late
• aging populations have made the 5-10 year risk predictions at age 50 less clinically relevent. the actual CVD risk in these individuals are likely to be higher in their remaining 40-50 years of life
• the risk algorithms are based on risks found in cohort studies in the late 20th century when CVD was much higher

Question 26

which strategies would be best for cardiovascular disease burden?

Answer 26

a combination of population-wide strategies and strategies targeted at high risk individuals is needed to reduce the cardiovascular disease burden

(population paradox)