Revision powerpoint - everything we need to know

Question 1

describe the epidemiological transition

Answer 1

changes in level and causes of mortality
decline in total mortality
reduction in infectious disease
increases relative role of chronic non-communicable disease - cancer, CVS, chronic resp disease, diabetes

Question 2

dynamic nature of the epidemiological transiotion

Answer 2

result of demographic, socioeconomic, technological, cultural , env and biological changes
small pox disappear, AIDS appear, TB denge re-emerge
decline in stomach cancer, rise and fall of lung cancer
shift from stroke to heart disease

Question 3

most commonly diagnosed cancer

Answer 3

lung, breast, colorectal

Question 4

most common cause of cancer death

Answer 4

lung liver and stomach

Question 5

burden of non-communicable disease

Answer 5

1/3 cancers likely to be preventable through small number of lifestyle and environmental approaches
smoking largest preventable casue of cancer worls wide
burden shift to less developed countries
incidence caries between populations

Question 6

cancer

Answer 6

major problem
>25% deaths world woide
in 2010 15.1% deaths - 8million died
canvcer rates in migrants converge to local rates
modifyable risk factors
take up to 20 years to appear
current rates affected by changes and exposure that took place in the past

Question 7

cancer risk factors

Answer 7

smoking 
low intake fruit/veg 
alcohol
unsafe sex
obesity
physical inactivity 
contaminated injections 
urban air pollution 
indoor smoke from household solid food use

Question 8

cancer from infections

Answer 8

hepititus - liver 
H pylori - gastric HPV - cervical 
EBV - hodgkins lymphoma, stomach cancer 
HIV - AIDS defining malignancies, Kaposi sarcoma, non-Hodgkin lymphoma, cervical cancer 
schistosomes - bladder cancer

Question 9

CVD

Answer 9

CHD and stroke 1st and 2nd cause specific mortality ww
29.5% all deaths - 15.6 million
more in developing world
low in japan
high and rising rates in formally socialist economies - Europe and middle east
rates higher in men than women - gap shrinking
trends declining in many countries recently
patterns suggest environment rather than genetics

Question 10

risk factors for CVD

Answer 10

high bp
tabacco smoking
cholesterol level

Question 11

commonest non-infectious cause of world mortality

Answer 11

ischemic heart disease

cerebrovascular disease

Question 12

where are infectious disease the leading cause of death

Answer 12

sub sarharan Africa

Question 13

6 commonest infectious cause of world mortality and some underlying high incidence

Answer 13

lower respiratory infections - 3.9m 
HIV 2.8m 
diarrheal disease - 1.8m 
TB - 1.6m 
malaria 1.2m 
measles 0.6m

Question 14

why is there a change in mortality and incidence of infectious disease

Answer 14

treatment 
exposure 
diagnosis 
screening 
treat and diagnose early - mortality decrease but incidence increase

Question 15

case

Answer 15

Person who has the disease, health disorder or suffers the event of interest

Question 16

incidence

Answer 16

Number of new cases of a disease within a specified time interval - probability or risk of developing a disease in a specific time period

Question 17

prevalence

Answer 17

Frequency of a disease in a population at a point in time (point prevalence) - proportion and measures status, for planning, compare burden between populations

Question 18

mortality

Answer 18

Number of deaths attributed to a specific condition in a given time period - number deaths per 1000 individuals per year

Question 19

morbidity

Answer 19

Number of cases of ill health, complications, side effects attributed to a specific condition over a particular time period.
- state of being unhealthy or diseased

Question 20

drivers of aids epidemic, success and challenges of the response

Answer 20

access to anti-retroviral therapy
effective HIV prevention methods - safe sex
decline in prevalence in pregnant women
to reduce incidence further need a vaccine
incident increase because of better diagnosis and better treatment - incidence increase and mortality decrease

Question 21

HIV infection - prevalence and mortality

Answer 21

incidence rising
mortaklity reduced because of HAART
duration of disease increasing
steep increase in prevalence

Question 22

routine data

Answer 22

data routinely collected

recorded in ongoing systematic way - for administrative or statuary purposes without specific research questions

Question 23

examples of routine data

Answer 23

deaths, hospital admissions, screening, immunisation uptakes, census counst, GP consultation data

Question 24

major sources routine data in UK

Answer 24

2001 Census
Health Survey for England
NHS Inpatient Survey on patient experience

Question 25

advantages of routine data

Answer 25

``` Relatively cheap Already collected and available Standardised collection procedures Relatively comprehensive – population coverage, large numbers Wide range of recorded items Available for past years ```

Question 26

disadvantages

Answer 26

``` not answer qn incomplete ascertainment variable quality validity variable disease labling vary need careful interpretation ```

Question 27

SMR

Answer 27

ratio between observed number of deaths in a study population and number of deaths would be expected - accounting for age and sex

Question 28

SMR =

Answer 28

no observed deaths/no expected deaths if same age specific rates as standard population

Question 29

age standardised death rates

Answer 29

measure how many people die each year and why they have dies assess effectiveness of a country's health system along with assessing how injuries and diseases affect the living - determine if focussing on the right thing that will prevent reducable deaths and disease

Question 30

main approaches of intervention to improve health

Answer 30

clinical intervention - biomedical, prevention health education healthy public policy eg smoking community development

Question 31

primordial prevention

Answer 31

prevention of factors which promote emergence of lifestyles, behaviours, exposure patterns which contribute to the risk of disease

Question 32

primary prevention

Answer 32

prevent the onset of disease - limit exposure of risk factor by individual behaviour change and actions in the community health promotion and specific protection

Question 33

secondary prevention

Answer 33

halt progression once illness is established - prompt effective treatment special consideration for asymptomatic

Question 34

tertiary prevention

Answer 34

rehab of people with established disease to minimise residual disabiliyu and complications QOL

Question 35

sample

Answer 35

group of people, objects or items taken from a larger population for measurement

Question 36

variation

Answer 36

variation of observations in a single sample

Question 37

what can you get from a sample

Answer 37

estimates of true underlying risks

Question 38

problem with sample

Answer 38

risk that association is die to chance

Question 39

p value

Answer 39

probability that the null hypothesis is tru

Question 40

null hypothesis

Answer 40

hypothesis that there is no significance

Question 41

attributable risk

Answer 41

difference in rate of a condition between exposed and unexposed population - guantifies the risk - fact

Question 42

relative risk

Answer 42

ratio of the probability of an event occurring in exposed group to probability of event occurring in comparison in a non-exposed group estimates magnitude of association

Question 43

attributable risk =

Answer 43

incidence in exposed- incidence in unexposed

Question 44

relative risk =

Answer 44

incidence in exposed/incidence in unexpoded

Question 45

odds ratio

Answer 45

likelihood of having exposure if you have disease relative to having exposure if no disease

Question 46

OR =

Answer 46

odds of exposure in cases/odds off exposure in controls

Question 47

confounding

Answer 47

mixing of effects between exposure, the disease and a 3rd factor

Question 48

dealing with confounding at desighn

Answer 48

randomisation - RCT | restriction/matching - case control

Question 49

dealing with confounding in analysis

Answer 49

stratification - split analysis by age group standardisation regression - build statistical model

Question 50

EBM

Answer 50

based on critical appraisal dr should use critically appraised information in clinical practice for optimal care developed over 30 years

Question 51

why EBM matters to clinicians

Answer 51

``` Patient Medical Knowledge Practice-Based Learning and Improvement Interpersonal and Communication skills Professionalism ```

Question 52

association

Answer 52

Association refers to the statistical dependence between two variables. Consider chance, bias, confounding, cause (CBCC)

Question 53

chance

Answer 53

from samples not whole pop

Question 54

bias

Answer 54

systematic - measurement/selection

Question 55

casual effect

Answer 55

A simple way to remember the meaning of causal effect is: B happened because of A, and the outcome of B is strong or weak depending how much of or how well A worked. Cause-effect relationship Judgement is based on a chain of logic that addresses two main areas: -Observed association between an exposure and a disease is valid -Totality of evidence taken from a number of sources supports a judgement of causality

Question 56

power calculations

Answer 56

to calculate minimum sample size for acceptable outcome

Question 57

responder bias

Answer 57

prevented by single blinding

Question 58

ecological studies

Answer 58

measure prevalence and incidence of disease, particularly when disease is rare. - observational study defined by the level at which data are analysed, namely at the population or group level, rather than individual level.

Question 59

case report

Answer 59

follow up of an individual patient

Question 60

descriptive/cross sectional

Answer 60

: Observational study that analyzes data collected from a population, or a representative subset, at a specific point in time

Question 61

strength

Answer 61

Measured by the magnitude of relative risk. Strong association is more likely to be causal and a weak association could be more easily the result of confounding or bias

Question 62

consistency

Answer 62

similar results in similar studies

Question 63

specificity - Bradford hill

Answer 63

particular exposure increasing the risk of a certain disease but not the risk of other diseases

Question 64

temporal relationship

Answer 64

For a putative risk factor to be the cause of a disease, it has to precede the disease.

Question 65

dose response relationship

Answer 65

Increasing levels of exposure lead to increasing risks of disease shows evidence of a causal effect.

Question 66

plausibility

Answer 66

consistant with other studies

Question 67

coherence

Answer 67

cause and effect doesn't conflict with what is known with the natural history

Question 68

experimental evidence

Answer 68

On humans (rarely available) or animals

Question 69

analogy

Answer 69

Provides a source of more elaborate hypotheses about the association in question. Absence only reflects lack of imagination or experience.

Question 70

clinical trial

Answer 70

A planned experiment in humans designed to measure the effectiveness of an intervention (usually a drug but can be surgical procedures, vaccine, complementary therapy etc)

Question 71

features of a clinical trial

Answer 71

Define your intervention Define your comparator • Placebo • Alternative treatment • Standard of care Define your inclusion criteria Define your exclusion criteria Experimental study Must contain a control group- to be sure why the outcome has occurred (could be due to the effectiveness of the new treatment or happened anyway) Prospective: participants are followed through time Patients are enrolled, treated and followed over the same period of time Patients should be randomised –to eliminate allocation bias

Question 72

block randomisation

Answer 72

assign people to group A or B randomly

Question 73

stratification

Answer 73

by important characteristic

Question 74

minimisation

Answer 74

adaptive stratification - calculates imbalance and allocates to maintain balance

Question 75

biases in clinical trials and how to avoid them

Answer 75

allocation bias - randomisation measurement bias - blinding reporting bias - selective reporting

Question 76

consort

Answer 76

consolidated standards of reporting trials - ensures papers about trials incude all relevant info

Question 77

outcomes of a clinical trial

Answer 77

The outcomes are presented in terms of efficacy (the true biological effect of a treatment) or effectiveness (effect of a treatment when actually used in “normal” practice).

Question 78

experimental event rate

Answer 78

incidence in intervention arm

Question 79

control event rate

Answer 79

incidence in control arm

Question 80

relative risk

Answer 80

eer/cer

Question 81

relative reduction

Answer 81

cer-eer/cer

Question 82

absolute risk reduction (ARR)

Answer 82

cer-eer

Question 83

number needed to treat

Answer 83

1/ARR

Question 84

what is included in a summary of information from a paper

Answer 84

``` Why did they do it? What did they do? What did they find? What did they conclude? In your opinion, was the study conducted well? ```

Question 85

critical appraisal cchecklist

Answer 85

``` Question – Relevant? Hypothesis? Design – appropriate? Population – sample size? Methods – measure? Appropriate? Analysis – appropriate statistical tests? Confounders Bias – measurement, selection Ethics – ethical? Consent? Interpretation – casual inference (Bradford Hill ```

Question 86

guidelines for different studies

Answer 86

RCT - consort observational studies - STROBE systematic reviews - PRISMA/MOOSE

Question 87

all or non-case series

Answer 87

when all patients died before a new therapy was introduced, yet following its introduction, all patients receiving the treatment survived

Question 88

why conduct a systematic review

Answer 88

high volume of data that needs to be considered | single studies are inefficient

Question 89

meta analysis

Answer 89

combine the published estimates of effects from each study to generate a pooled risk estimate

Question 90

what is a systematic review

Answer 90

review of a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant research and analyse data from studies that are collected in the review

Question 91

stages of systematic review

Answer 91

1 - planning 2 - identify research, select studies, study quaaltity assessment 3 - report and dissemination, study details abstracted and details tabulated to show summary of findings - estimate overall effect using a meta analysis

Question 92

meta analysis

Answer 92

combine the published estimates of effects from each study to generate a pooled risk estimate if too heterogenous might be inappropriate to pool

Question 93

why do a meta analysis

Answer 93

more reliable and precise estimate of effect difference between studies identified and explored get pooled weighted average

Question 94

presenting a meta analysis

Answer 94

forest plot each study represented with a box and line size of box = weight given to the study line = 95% confidence interval overall estimate is the diamond centre of diamond and line - summary effect estimate width of the diamond = CI around estimate

Question 95

bias and limitation of systematic review

Answer 95

publication bias inconsistency low study quality heterogeneity

Question 96

publication biasd

Answer 96

cause data to be over or under estimated | explored with funnel plots - show if link between study size/precision and the effect of the estimate

Question 97

what is screening

Answer 97

investigating apparently healthy individuals to detect unrecognised disease or its precursers so measures can be taken to prevent or delay the development of disease or improve prognosis

Question 98

why screen

Answer 98

when early diagnosis = better prognosis high risk - intervention = better prognosis identification of those posing risk to others - eg infectious disease eg Hep B

Question 99

mass screening programs in the UK

Answer 99

``` cervical cancer breast cancer bowel cancer abdominal aortic aneurysm diabetic eye screening ```

Question 100

cervical screening

Answer 100

every 3yrs 25-49 | 5yrs - 50-64

Question 101

breast screening

Answer 101

3yrds 50-70 | >70 can self refer

Question 102

bowel screening

Answer 102

2yrs men and women 60-74

Question 103

abdominal aortic aneurysm

Answer 103

men 65th year

Question 104

diabetic eye screening

Answer 104

people with T1/T2 DM >12

Question 105

validity of screening test

Answer 105

ability to distinguish between those with the condition and those without

Question 106

gold standard

Answer 106

a recognised way of determining who has the disease

Question 107

sensitivity

Answer 107

ability of test to correctly identify people with the disease (true positives)

Question 108

specificity

Answer 108

Ability of the test to correctly identify people without the disease (ability to exclude true negatives)

Question 109

predictive value

Answer 109

Proportion of test results that are correct | dependent on the sensitivity and specificity and the prevalence of the condition in the population

Question 110

+ve predictive value

Answer 110

likelihood that a patient with a positive test result will actually have the disease

Question 111

-ve predictive value

Answer 111

likelihood that a patient with a negative test result will not have the disease

Question 112

receiver operator characteristics curves

Answer 112

are used to determine a cut-off value for a diagnostic or screening test. Y axis- sensitivity vs 1-specificty (x-asis)

Question 113

how do you choose cut off value

Answer 113

is informed by the attempt to maximise sensitivity and specificity

Question 114

criteria for screening

Answer 114

``` feasibility effective selection bias lead time bias length time bias cost ethics ```

Question 115

ethics

Answer 115

- May harm as well as benefit the individual - Risks of the test - Risks of subsequent diagnostic tests - Risks of subsequent treatment - False positive result causes unnecessary anxiety - False negative result will give false reassurance

Question 116

feasibity

Answer 116

easy to get attendance acceptable facilities for diagnostic tests

Question 117

effectiveness

Answer 117

extent it affects subsequent outcomes

Question 118

selection bias

Answer 118

people who participate are different to those that don't

Question 119

lead tiem bias

Answer 119

improvement really due to earlier date of diagnosis

Question 120

length time bias

Answer 120

some conditions slower in developing to a health threatening phase - more likely to be detected at a stage that has favourable prognosis - false conclusion that screening is beneficial

Question 121

cost

Answer 121

includes the diagnostic test and treatment in comparison to costs of treatment of more advanced disease