Lec 4

Question 1

what is the aim of a research study for an optometrist

Answer 1

to underpin understanding of clinical and health research methods relevant to the practising optometrist

Question 2

what are the 2 types of EBM

Answer 2

• primary research

- secondary research

Question 3

what is primary research

Answer 3

• it is written by the researchers themselves
• usually in journals or articles
• it is the outcome of a single study
• peer reviewed

Question 4

what is secondary research

Answer 4

• summarises findings of multiple trials, experiments or surveys on the same topic
  (answering a research question by looking at research papers produced by others)

Question 5

what is the aim of a experiment in clinical research

Answer 5

proving or contradicting a hypothesis with data

Question 6

what is a experiment in clinical research interested in

Answer 6

interested in an outcome (dependent) which may be influenced by an attribute (independent)

in the form of an EBM

e.g. does smoking cause AMD

Question 7

name the 2 primary research study types

Answer 7

• observational studies
• experimental studies (clinical trials)

which are 2 different ways of answering a hypothesis

Question 8

how does an observational study work

Answer 8

the investigator has no control over exposures to risk or treatments and instead observes what happens to groups of people

Question 9

how does a experimental study (clinical trial) work

Answer 9

conditions are under the direct control of the investigator

e.g. select a sample of people and follow up with them and a control group in X amount of years and then notice a pattern

Question 10

which type of primary research study type provides the best evidence for clinical research and why

Answer 10

experimental studies (clinical trials)

as it is the best way to prove something, we do something/there is an intervention

Question 11

what are the 3 forms of study in observational studies and when does each occur

Answer 11

• retrospective study - in the past
• present time
• prospective study - in the future

Question 12

name the 4 types of observational studies and what differentiates them

Answer 12

• case reports
• case-control study
• cross-sectional study
• cohort study

the time when the studies were done

Question 13

which 2 types of study is a retrospective study (done in the past)

Answer 13

• case reports
• case-control study

information and data were done in the past

Question 14

which type of study is carried out at present and give an example

Answer 14

cross sectional study e.g. a survey

Question 15

which type of study is a prospective study (done in the future)

Answer 15

cohort study

Question 16

which type of retrospective study is typically done on one person

Answer 16

case report

Question 17

give an example of how a case report is carried out

Answer 17

• look through patient records
• e.g. select a patient with AMD
• assess whether they are smokers

Question 18

name the advantages of a case report

Answer 18

quick, simple and cheap

Question 19

name the disadvantage of a case report

Answer 19

no control group - px may have developed AMD anyway, so not sure if its to to with the attribute your looking at or to do with the person itself

Question 20

which type of retrospective study is considered to be at the bottom of the hierarchy of EBM and why

Answer 20

case reports

it is a type of anecdotal evidence and carries the least weight

Question 21

what can a case report lead to

Answer 21

bigger sorts of questions

Question 22

what is the next best type of retrospective study to do if you dont have a case report

Answer 22

case-control study

Question 23

what is the difference between a case report and a case-control type of retrospective study

Answer 23

case-control type has control group

Question 24

list the advantages of a case control study

Answer 24

• relatively easy to do

- provides a measure of risk of smoking beyond chance (compared to what it would be if your won’t a smoker)

Question 25

what can be difficult with a case-control study

Answer 25

selecting the 'matched' control group e.g. it is difficult to make sure your control group are exactly the same as the patient with the AMD, but only difference is they haven't got AMD = hard to match the group

Question 26

list 3 disadvantages of a case-control study

Answer 26

- recall bias - inaccuracy of retrospective data - detection bias

Question 27

how is recall bias a disadvantage of a case-control study

Answer 27

it is interviewing and selectively recalling past event - it is done by other people, so may not have real truth in it especially if it is remembered and not recorded as this can be forgotten

Question 28

what is an example of inaccuracy of retrospective data, as a disadvantage of a case-control study

Answer 28

incomplete hospital notes so your relying on other people to collect the data and not done yourself so the information may not be collected properly

Question 29

explain how detection bias is a disadvantage of a case-control study

Answer 29

exposure related to risk of detection e.g. diabetes or obesity the way we collect our data is important as well

Question 30

how are cross-sectional studies carried out

Answer 30

done via a survey or questionnaire, done in one snapshot at a time/at present

Question 31

what is another work for prospective observational studies

Answer 31

longitudinal studies

Question 32

what is the idea of a prospective/cohort study

Answer 32

to identify a study group and follow them in the future

Question 33

what is the advantages of a prospective/cohort study

Answer 33

- better data and extra information | - no recall bias and people entering the data incorrectly

Question 34

list the 3 disadvantages of a prospective/cohort study

Answer 34

- long and expensive - loss to follow up (subjects change habits, move or die) - surveillance bias (at risk group is monitored too closely) e.g. done too carefully which is how you wouldn't normally do it in real life

Question 35

what arises in all observational studies

Answer 35

confounding

Question 36

what is a confounder

Answer 36

a 3rd variable which explains or masks the observational effect

Question 37

how can you figure out the confounders

Answer 37

it is to match the people your looking at with controls

Question 38

how can you avoid confounding

Answer 38

by careful matching

Question 39

what is the confounder in 'number of limb fractures is lower in student nurses than in the age-matched university population of the same size'

Answer 39

gender

Question 40

what is the confounder in 'several published observational studies have indicated a high rate of lung cancer in professional chefs'

Answer 40

gender, smokers, stress

Question 41

what is the confounder in 'a published study indicates that myopia development in children is affected by ambient light in the bedroom'

Answer 41

genetic/parents

Question 42

list the hierarchy of observational studies from highest to lowest rank

Answer 42

1. cohort studies 2. case-control studies 3. cross-sectional studies 4. case reports