The Use of Data - FoPC 2 Tutorial 2

Question 1

What is General Practice the interface between? (2)

Answer 1

The public and secondary care

Question 2

What percenatge of the population consult their GP? (1)

Answer 2

20%

Question 3

What percenatge of the population are given referrals to secondary care? (1)

Answer 3

3%

Question 4

What percentage of people ignore their symptoms? (1)

Answer 4

19%

Question 5

What percentage of people treated their issues withoit medical advice or w/self medication? (1)

Answer 5

56%

Question 6

Is the progression through levels of medical care related to the severity of disease (2)

Answer 6

Sort of, most patients who look after themselves tend to have self-limiting illnesses while those with more lifethreatening illnesses are in hospital. Not entirely true as severity of illness doesnt indicate severity of disease

Question 7

Define Disease (using FoPC buzzwords)

Answer 7

Symptoms/signs leading to a diagnosis (biomedical persepctive of disease)

Question 8

Define Illness (using FoPC buzzwords)

Answer 8

Ideas, concerns, expectations -> patients experience/perspective of

Question 9

Example of a disease without an illness (1)

Answer 9

Hypertention

Question 10

What issue may have to be considered when treating a disease without an illness?

Answer 10

Non-compliance (patient feels no different and stops taking meds for hypertentention)

Question 11

What factors affect the uptake of care (no detail, just list - 4)?

Answer 11

Concept of lay referral Sources of info about healthcare Medical Non-medical factors

Question 12

What is the concept of lay referral?

Answer 12

Granny knows best (because why should FoPC use plain english)

Question 13

What sources of informtion might affect patients uptake of care? (8)

Answer 13

Peers Family Internet TV Healthpages in magazines and newspapers “What should I do?” booklet SHOW website Practice leaflet/website

Question 14

What medical factors affect patients uptake of care? (4)

Answer 14

New symptoms Visible symptoms Increasing severity Duration

Question 15

What non-medical factors affect patients uptake of care? (13)

Answer 15

Crisis Peer Pressure “wife sent me” Patient beliefs Expectations Social class (FoPC yr 1) Economic Pyschological Environmental Cultural Ethnic Age Gender Media

Question 16

What are the three main aims of Epidemiology? (3 + detail)

Answer 16

Description - To describe the amount and distribution of disease in human populations. Explanation - To elucidate the natural history and identify aetiological factors for disease usually by combining epidemiological data with data from other disciplines such as biochemistry, occupational health and genetics. Disease control - To provide the basis on which preventive measures, public health practices and therapeutic strategies can be developed, implemented, monitored and evaluated for the purposes of disease control.

Question 17

Why does epidemiology involve comparing groups? (3)

Answer 17

to detect differences that point to: - Aetiological clues (what causes the problem) - Scope for prevention - Identification of high risk or priority groups in society

Question 18

What is compared in epidemiology?

Answer 18

You compare how often an event appears in one group with another similar group - may be defined by age/sex/location or even the same group over time

Question 19

What is the difference between clinical medicine and epidemiology?

Answer 19

Clinical medicine dealths with individual patients while epidemiology deals with populations

Question 20

Define “Incidence”

Answer 20

The number of new cases of a disease in a population in a specified period of time.

Question 21

What does incidence tell us?

Answer 21

Incidence tells us something about trends in causation and the aetiology of disease.

Question 22

Define “Prevalence”

Answer 22

The number of people in a population with a specific disease at a single point in time or in a defined period of time.

Question 23

What does prevalence tell us?

Answer 23

Prevalence tells us something about the amount of disease in a population. It is useful in assessing the workload for the health service but is less useful in studying the causes of disease.

Question 24

Can you have lifetime prevelance?

Answer 24

Yes It just depends on the number of people developing a disease, dying from it or recovering from it

Question 25

Define "Relative risk"

Answer 25

The measure of the strength of an association between a suspected risk factor and the disease under study

Question 26

What is the "equation" used to calculate relative risk

Answer 26

'Incidence of disease in exposed group' divided by 'Incidence of disease in unexposed group'

Question 27

Name some sources of epidemiological data (12)

Answer 27

Mortality data Hospital and clinical activity statistics Reproductive health statistics Infectious disease statistics Cancer statistics Accident statistics General practice morbidity statistics Health and household surveys Labour force surveys Social security statistics Drug misuse databases Expenditure data from NHS

Question 28

What is health literacy?

Answer 28

Health literacy is about people having the knowledge, skills, understanding and confidence to use health information, to be active partners in their care, and to navigate health and social care systems.

Question 29

What are NOACs (this is FoPC not cardio remember)? (3)

Answer 29

Newer drugs that dont require regular blood tests They are relatively inexpensive They are not easily reversed in the event of bleeding

Question 30

List the 2 main study types

Answer 30

Descriptive Analytical

Question 31

What does a Descriptive study attempt to do?

Answer 31

They attempt to describe the amount and distribtution of a disease in a given population for the purposes of gaining insight into the aetiology of the condition or for planning health services to meet clinical need

Question 32

What might descriprive studies look at?

Answer 32

Disease alone or they also examine one or more factors (Exposures) that might be linked to the aetiololgy

Question 33

What framework do descriptive studies follow?

Answer 33

Time, Place and Person framework

Question 34

When are descriptive epidemiological studies useful?

Answer 34

Identifying emerging public health problems through monitoring and surveillance of disease patterns Signalling

Question 35

When are descriptive epidemiological studies useful? (4)

Answer 35

Identifying emerging public health problems through monitoring and surveillance of disease patterns Signalling presence of effects worthy of further investigation Assessing needs for health services and sevice planning Generating Hypotheses about disease aetiology

Question 36

List the types of Analytical studies (3 Cs)

Answer 36

Cross-sectional Cohort Case control

Question 37

What is a Cross-sectional study? (3)

Answer 37

Disease frequency, Survery and Prevalence study

Question 38

What happens in a cross sectional study? (2)

Answer 38

Observations are made at a single point in time Conclusions are drawn about the relationship between diseases (or health-related characteristics) and other variables of interest in a defined population

Question 39

What is an advantage of using then crossectional study method?

Answer 39

It produces results quickly

Question 40

What is a disadvantage to crossectional studies?

Answer 40

They are impossible to infer causations from

Question 41

What happens in a case control study?

Answer 41

two groups of people are compared - those with the disease of interest and those without the disease data is then gathered in each individualto determine whether they have been exposed to the suspected aetiological factor The average exposure in the two groups is then compared to identify significant differences and give clues to factors which elevate risk of the disease under investigation.

Question 42

Define 'Cases' in a case controlled study

Answer 42

A group individuals with the disease of interest

Question 43

Define 'controls' in a case controlled study

Answer 43

A group of individuals who do not have the disease

Question 44

What happens in a Cohort study?

Answer 44

Baseline data on exposure are collected from a group of people who do not have the disease under study. The group is then followed through time until a sufficient number have developed the disease to allow analysis. The original group is separated into subgroups according to original exposure status and these subgroups are compared to determine the incidence of disease according to exposure.

Question 45

What do cohort studies allow?

Answer 45

They allow for the calculation of cumulative incidence, allowing for differences in follow up time

Question 46

Define a 'trial' (in relationto epedimiology)

Answer 46

Trials are experiments used to test ideas about aetiology or to evaluate interventions.

Question 47

What is the definitive methof of assessing new treatments?

Answer 47

Randomised controlled trial

Question 48

What does a randomised controlled trial involve?

Answer 48

Two groups at risk of developing a disease are assembled, a study (intervention) group and a control group. An alteration is made to the intervention group (eg, a suspected causative factor is removed or neutralised), whilst no alteration is made to the control group. Data on subsequent outcomes (eg, disease incidence) are collected in the same way from both groups, and the relative risk is calculated.

Question 49

What is the aim of a randomised controlled trial?

Answer 49

The aim is to determine whether modification of the factor (removing, reducing or increasing exposure) alters the incidence of the disease)

Question 50

What factors must be considered when interpreting results? ()

Answer 50

Standardisation Standardised Mortality Ratio Quality of Data Case Deifinition Coding and Classification Ascertainment

Question 51

Explain 'Standardisation'

Answer 51

A set of techniques used to remove (or adjust for) the effects of differences in age or other confounding variables (sex, social class etc.), when comparing two or more populations

Question 52

Explain the 'Standardised Mortality Ratio (SMR)'

Answer 52

A standardised death rate converted into a ratio for easy comparison

Question 53

Why is the quality of data important?

Answer 53

We have to ensure the data we use is trustworthy

Question 54

What is the purpose of a case definition?

Answer 54

Its purpose is to deciden whether an individual has the condtiion of interest or not.

Question 55

Why is the case deifintion important?

Answer 55

It is important in because not all doctors or investigators mean the same thing when they use medical terms. Differences in incidence of disease over time or in different populations may be artefact, due to differences in case definition, rather than differences in true incidence.

Question 56

Why are fixed rules relating to classification and coding important?

Answer 56

Rules are drawn up to dictate how clinical information is converted to a code. They ensure information is accurate. If these rules change, it sometimes appears that a disease has become more common, or less common, when in fact it has just been coded under a new heading.

Question 57

Define 'Bias'

Answer 57

Any trend in the collection, analysis, interpretation, publication or review of data that can lead to conclusions that are systematically different from the truth.

Question 58

List the 5 important types of bias

Answer 58

Selection Bias Information Bias Follow up Bias Systematic Error Publication bias

Question 59

When does selection bias occur?

Answer 59

When the study sample is not truly representative of the whole study population about which conclusions are to be drawn

Question 60

Give an example that illustrates selection bias

Answer 60

In a randomised controlled trial of a new drug, subjects should be allocated to the intervention (study) group and control group using a random method. If certain types of people (eg, older, more ill) were deliberately allocated to one of these groups then the results of the trial would reflect these differences, not just the effect of the drug.

Question 61

Where does information bias arise?

Answer 61

Arises from systematic errors in measuring exposure or disease

Question 62

Give an example that illustrates information bias

Answer 62

In a case control study, a researcher who was aware of whether the patient being interviewed was a 'case' or a 'control' might encourage cases more than controls to think hard about past exposures to the factors of interest. Any differences in exposure would then reflect the enthusiasm of the researcher as well as any true difference in exposure between the two groups.

Question 63

When does 'Follow up bias' arise?

Answer 63

When one group of subjects is followed up more assiduously than another to measure disease incidence or other relevant outcome.

Question 64

Give an example that illustrates 'Follow up bias'

Answer 64

In cohort studies, subjects sometimes move address or fail to reply to questionnaires sent out by the researchers. If greater attempts are made to trace these missing subjects from the group with greater initial exposure to a factor of interest than from the group with less exposure, the resulting relative risk would be based on a (relative) underestimate of the incidence in the less exposed group compared with the more exposed group.

Question 65

What is a 'Systematic error'?

Answer 65

A form of measurement bias where there is a tendency for measurements to always fall on one side of the true value.

Question 66

Why may a systemic error occur?

Answer 66

It may be because the instrument (eg, a blood pressure machine) is calibrated wrongly, or because of the way a person uses an instrument.

Question 67

Where might systematic errors occur? (3)

Answer 67

Interviews Questionnaires Medical instruments

Question 68

When does 'Publication Bias' occur?

Answer 68

Occurs where positive results have a greater chance of being published (even if the quality of the study is poorer than a similar study showing negative results)

Question 69

Define 'Confounding Factors'

Answer 69

One which is associated independently with both the disease and with the exposure under investigation and so distorts the relationship between the exposure and disease In some cases the confounding factor may be the true causal factor, and not the exposure that is under consideration

Question 70

List three common confounding factors

Answer 70

Age Sex Social class

Question 71

Explain 5 ways confoudnig factors can be managed

Answer 71

In trials, the process of randomisation (in effect the play of chance leads to similar proportions of subjects with particular confounding in the intervention and control groups). Restriction of eligibility criteria to only certain kinds of study subjects . Subjects in different groups can be matched for likely confounding factors. Results can be stratified according to confounding factors. Results can be adjusted (using multivariate analysis techniques) to take account of suspected confounding factors.

Question 72

List the 9 criteria for causality

Answer 72

Strength of association Consistency Specificity Temporality Biological gradient Biological plausibility Coherence Analogy Experiment

Question 73

Define 'Consistency'

Answer 73

Repeated observation of an association in different populations under different circumstances.

Question 74

Explain what is meant by 'Temporality'

Answer 74

The exposure comes before the disease.

Question 75

How is strength of association measured?

Answer 75

Relative risk or odds ratio

Question 76

What term describes "a single exposure leading to a single disease"?

Answer 76

Specificity

Question 77

Explain what is meant by 'Biological gradient'

Answer 77

Dose-response relationship. As the exposure increases so does the risk of disease.

Question 78

Explain what is meant by 'Biological plausibility'

Answer 78

The association agrees with what is known about the biology of the disease.

Question 79

Explain what is meant by 'Coherence'

Answer 79

The association does not conflict with what is known about the biology of the disease.

Question 80

What does 'analogy' mean?

Answer 80

Another exposure-disease relationship exists which can act as a model for the one under investigation. For example, it is known that certain drugs can cross the placenta and cause birth defects - it might be possible for viruses to do the same.

Question 81

How can the audit criteria and standards to measure be set? (2)

Answer 81

Could define own Could utilise others if available

Question 82

What are the disadvantages of defining your own audit criteria and standards? (2)

Answer 82

Time consuming Needs more research

Question 83

What is the advantage of using others audit criteria and standards? (1)

Answer 83

Guidelines are based on systematic review of evidence