Clinical trials

Question 1

why don’t we like before and after studies

Answer 1

due to regression to the mean

Question 2

regression to the mean

Answer 2

take most extreme populate with intervention and will always tend to regress to the mean

Question 3

regression…. extended

Answer 3

reason people have joined the study [predisposed to an upswing
i.e. usually both arms of the trial will improve

e.g. someone with bad migraines- migraines ill tend to get better e.g. just by talkingg and being reassured by the doctor

Question 4

due to regression to the mean

Answer 4

we must be sceptical

Question 5

example of variable dependent variables

Answer 5

e. g. did have high bp, then goes down to normal at T2
- however someone from T1 with normal BP may have high BP at T2

-population stays the same, but people move in the population

due to upswings and downswings

Question 6

after new findings how long doe it take for clear, widespread practice to start in hospitals

Answer 6

17 years on average e.g. cortisone

however only 2 years for artificial surfactant- money and companies

Question 7

why do we randomise

Answer 7

best way of making differences in baseline in groups only occur due to change
- want differences at baseline to be due to chance rather than systematic on one way or another

Question 8

randomisation means that

Answer 8

it is the manipulation of treatment which manipulates the data and not confounding variables

Question 9

statistics help us with

Answer 9

chance differences

Question 10

statistics do not help us with

Answer 10

systematic differences

Question 11

why manipulate data

Answer 11

• a desire for a positive outcome
• stop money feeling wasted
• much more likely to get published in big journal
• get famous

Question 12

why is there a need for allocation concealment

Answer 12

if clinicians are part of the trial they may want to give their patients the active treatment- can be conscious or unconscious

Question 13

allocation concealment

Answer 13

around 30% diff in effect

Question 14

getting the question right

Answer 14

i.e. if the study has addressed a male population, the results shouldn’t be extrapolate for females

Question 15

questions to answer

Answer 15

is the research valid?

is it applicable to the problem

Question 16

clinical problem vs study question

Answer 16

PICOs should match

Question 17

example PICO

Answer 17

P people who have snakebites in rural india, treated with anti-venom
I adrenaline, anti-venom
C antihistamine , steroid. Anti-venom along
O deaths, morbidity, mortality, cost

Question 18

randomisation involves

Answer 18

how allocation of groups occured

Question 19

what can be used to randomise

Answer 19

can be computer generated- no bas

Question 20

randomisation ensures that

Answer 20

differences in demographic groups are just due to chance and reduces ALLOCATION BIAS

Question 21

in clinical trial papers it is important to show

Answer 21

the extent where baseline characteristics int he two groups are similar
e.g. sex, age, species of snake, delay in admission to hospital, first aid, worst outcmes

Question 22

important to show baseline characterisitcs

Answer 22

so countries can see ow relevant data is for their populations- allow additional studies

Question 23

Follow up- complete and long-enough?

Answer 23

• neurological evaluations?
• Kept in hospital?
• adverse reactions with graded criteria
• monitored for 96h
• long term check up?

Question 24

why are follow ups important to record

Answer 24

allows future researchers to know what possible adverse effects could be

Question 25

blinding

Answer 25

ensure both groups are treated the same

Question 26

why should we blind

Answer 26

• clinicians- way change the way they manage patients
• patients- placebo effect
• researchers- outcome measurers- clearly objective

Question 27

stats cannot be used for

Answer 27

baseline variation

Question 28

what does a p value of 0.04 mean

Answer 28

if we did an infinite number of studies of this size 4% of the time we would get results like this more more extreme, if there was no difference

Question 29

what drives p value

Answer 29

sample size and variation