Use of Data

Question 1

Epidemiology in providing information aims? (3)

Answer 1

Description (amount and distribution of disease)
Explanation (natural history & aetiological factors of disease)
Disease control (preventative measures, PH practices and therapeutic strategies)

Question 2

what is relative risk?

Answer 2

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

RR = incidence of disease in exposed group
incidence of disease in unexposed group

Question 3

sources of epidemiological data? (6)

Answer 3

mortality data
cancer statistics
accident statistics
health and household studies
social security statistics
expenditure data from NHS

Question 4

what is health literary?

Answer 4

people

Question 5

why is it important to know how common a problem is?

Answer 5

to aid in planning and costing

Question 6

what is the purpose of SIGN guidelines? (2)

Answer 6

help health and social care professionals and patients to understand medical evidence and use it to make healthcare decisions

improve healthcare across Scotland by focusing on patient-important outcomes

Question 7

what is descriptive studies?

Answer 7

these studies attempt to describe the amount and distribution of a disease in a given population

follow the time, place, person framework

Question 8

what do descriptive studies provide?

Answer 8

gives clues on possible risk factors and candidate aetiologies

cheap, quick and give valuable initial overview of a problem

Question 9

what are cross-sectional studies?

Answer 9

disease frequency, survey, prevalence study

single point in time

In cross-sectional studies, observations are made at a single point in time.
Conclusions are drawn about the relationship between diseases (or other health-related characteristics) and other variables of interest in a defined population.
A strength of this method is its ability to provide results quickly; impossible to infer causation.

Question 10

what are case control studies?

Answer 10

two groups of people are compared

a group of individuals who have the disease of interest are identified (cases)

a group of people without the disease (control)

Question 11

what data is gathered in case control studies?

Answer 11

data gathered on whether or not the person has been exposed to the suspected aetiological factor and then the average exposure of each group looked at

Question 12

what are cohort studies?

Answer 12

in these studies 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

Question 13

what do cohort studies allow?

Answer 13

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

Question 14

what are trials?

Answer 14

trials are experiments used to test ideas about aetiology or to evaluate interventions

Question 15

assessing a new treatment in medicine?

Answer 15

the randomised controlled trial is the definitive method of assessing any new treatment in medicine

Question 16

what happens in the trial of a new treatment?

Answer 16

In a trial of a new treatment, the underlying design is the same: the intervention group receive the new therapy, the control group receive the current standard therapy (or a placebo) and the treatment outcomes (eg, reduction in symptoms) are compared in the two groups

Question 17

factors to consider when interpreting results? (6)

Answer 17

standardisation
standardised mortality ratio
quality of data
case definition
coding and classification
ascertainment

Question 18

what is standardisation?

Answer 18

a set of techniques used to remove or adjust the effects of differences in age or other confounding variable

Question 19

what is standardised mortality ratio (SMR)?

Answer 19

standardised death rate converted into a ratio

for example reference figure in a population of 100 and a figure below this means fewer than expected deaths and above means more

Question 20

what is the quality of the data?

Answer 20

careful consideration on the reliability of the source

Question 21

what is case definition?

Answer 21

whether the person has the condition or not

Question 22

what is coding and classification?

Answer 22

disease information is converted to a set of codes

Question 23

what is ascertainment?

Answer 23

is the data complete? are any subjects missing?

Question 24

what are the types of bias? (4)

Answer 24

selection bias
information bias
follow up bias
systematic error