Lecture 21: Cardiovascular Risk Assessment Flashcards
what is relative risk?
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
what is absolute risk?
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
what is the framingham risk score?
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.
what does absolute risk depend on?
multiple different factors
how does aboslute risk depend on multiple risk factors?
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
how do you estimate CVD risk?
- 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
what guidelines does NZ use?
- 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
what is involved in the NZ Cardiovascular disease risk assessment?
- 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
when do you start risk assessments for men and women without known risk factors?
men: 45 years
women: 55 years
when do you start risk assessments for maori, pacific and south-asian men and women ?
men: 35 years
women: 45 years
when do you start risk assessments for men and women with family history risk factors? what are the family history risk factors?
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
when do you start risk assessments for men and women with personal history risk factors? what are the personal history risk factors?
men: 35 years
women: 45 years
- people who smoke
- gestational diabetes
- HbA1C 41-49mmol/mol
- BMI ≥30 or truncal obesity
- atrial fibrillation
when do you start risk assessments for men and women with diabetes?
from the time of diagnosis
when do you start risk assessments for men and women with severe mental illness?
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.
what are the variables of CVD?
- 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
what is the shared treatment decision if someone has <5 percent CVD risk?
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
what is the shared treatment decision if someone has 5-15 percent CVD risk?
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
what is the shared treatment decision if someone has >15 percent CVD risk?
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
what is the shared treatment decision if there is estabilished CVD?
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
what are the targets for lipids?
- drug treatment if TC/HDL ratio ≥ 8 regardless of CVD risk
- if CVD risk ≥15%, target LDL below 1.8mmol/L
what are the targets for blood pressure?
- 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)
what are the targets for diabetes?
HbA1C 50-55mmol/mol for younger and fitter patients, or 55-64 mmol/mol for older co-morbid and frail patients
what is clinical judgement? when should it be used?
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
what is the strength of risk scoring?
- 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.
what are some issues with cardiovascular risk assessment?
- 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
which strategies would be best for cardiovascular disease burden?
a combination of population-wide strategies and strategies targeted at high risk individuals is needed to reduce the cardiovascular disease burden
(population paradox)
