lecture 19 - critical appraisal II

Question 1

what should the study population state in a peer?

Answer 1

fair recruitment for example, random recruitment from a treatment centre
recruitment of consecutive patients in a treatment centre

relevancy of exclusion and inclusion criteria - should not exclude subjects with a specific characteristic

Question 2

what are primary and secondary outcomes?

Answer 2

A primary outcome is the pre-specified outcome.
considered to be the most important outcome of the study
best to have only one primary outcome in a study

Secondary outcomes are additional outcomes of interest.
the study is often not powered to detect differences between groups in these outcomes

Question 3

what are not true randomisation methods?

Answer 3

date of birth
day of the week
medical record number
month of the year
the order in which they are recruited to the study

Question 4

what is double blinding ?

Answer 4

minimises measurement bias
both patients and investigators are unaware of treatment allocation is ideal
sometimes this may not be possible (where the intervention involves a physical treatment or surgery or where adverse effects of a drug clearly compromise blinding

Question 5

what is single blinding ?

Answer 5

where either one of the patients or the assessors are unaware of treatment allocation
may be acceptable in certain circumstances, depending on study design

Question 6

give example of objective and subjective outcomes

Answer 6

If the outcome is highly objective (e.g. death)
the requirement for blinding may be less critical
measurement bias should not really affect the result

if the outcome is subjective (e.g. self-rated symptoms or function)
blinding of the assessor may be crucial to avoid the influence of bias on the result