All Flashcards
(21 cards)
What are the two key aspects of clinical trail purpose
Efficacy = the ability of a health care intervention to
improve the health of a defined group under specific
conditions
Safety=the ability of a health care intervention not toharm a defined group under specific conditions
What is the placebo effect
“Even if the therapy is irrelevant to the
patient’s condition, the patient’s attitude tohis or her illness, and indeed the illness itself, may be improved by a feeling that
something is being done about it”
Define HaDPop
The science and art of preventing disease, prolonging life and promoting, protecting and improving health through the organised efforts of society
Define consensus and list useful functions
Simultaneous recording of all demographic data to all persons in an area
- allocation of resources
- projections of populations
- trends in population ethnicity or age
Explain the 3 types of birth rate
Crude birth - number of live births per 1000
General fertility rate - number of live births per 1000 fertile women 15-44
Total period fertility - average number of children born to a hypothetical women in her lifetime
Define:
Incidence
Prevalence
Incidence is the number of new cases of a disease per 1000 per year
Prevalence is amount of people who currently have a disease in a set population with no time frame
What is incidence rate ratio
Incidence rates of two separated populations with different exposure levels - these are compared to see if exposure causes disease
A - 300 diagnosed in pop of 30000 over 2 years
B - 400 diagnosed in pop of 60000 over 3 years
(300/(30000X2)) / (400/(60000X3)) = 2.25
So, you are 2.25 times more likely to get disease in area B
Define confounding variable
Something that is associated with both the outcome and the exposure of interest, but is not the casual pathway between the two
Define standardised mortality rate and give the equation
SMR takes into account confounding variables to provide summarise figure describing mortality
Observed number of death / expected number of death X 100
What is variation
Occurs where there is a difference between ‘observed’ and ‘actual’ value
To allow for these, an error factor is produced which is used to calculate confident intervals
What is a confidence interval
A range of values that we can say with confidence, that the actual value will lie in-between this range in 95% of cases.
This is produced by error factors
Define bias and give two umbrella terms
A systematic error that results in an incorrect estimate of true effect on exposure of the outcome.
1) information bias - error due to systematic misclassification of subject
- recall bias
- publication bias
2 selection bias - error due to systematic dif in way groups wr collected
- allocation bias
- healthy worker effect
What is healthy worker effect
Selection bias
Whereby a study involves workers compared to a reference population
A worker is more likely to healthy cf unemployed
Always need to test someone against some else working in same place
List six aspects that are involved in RCT trial
Identify a source of eligible patients Invite eligible patients to trial Allocate to treatment - randomised Follow up participants in identical ways Minimise loses and maximise compliance Analyse data and obtain results
What are the 5 ethical considerations of RCT
Clinical equipoise Scientifically robust Ethical recruitment Valid consent Voluntariness
What is the Bradford-Hill Criteria
To determine whether causal-effect has been established, and to evaluate the relationship
- the more criteria present, the more likely it is a causal-effect relationship
What is a systematic review and give 5 advantages
A complication of primary studies (tend to be RCT, cohort or case-control)
- explicit methods can reduce bias and exclude poor quality studies
- meta analysis provides overall figure for study
- large amount of info assimilated quickly
- reduction in time between research discover and clinical implementation
- used in evidence-based practice
What is a meta-analysis, and what are the two types of model
This a square section within the circle that is systematic review - it provides a quanta five synthesis of primary studies used in the trial.
Fixed effects model - assumes studies homogenous and variation comes from within study
Random effects model - assumes studies are heterogenous and variation comes from within study and between study
Define clinical trial
Any formof planned experiment which involvespatients and is designed to elucidate the most appropriate method of treatment of future
patients with a given medical condition”
If observed an apparent association between exposure and outcome what could this be due to (4 points)
Real association
Due to chance
Due to bias
Due to confounding variable
What are two main types of study design and examples of each
Observational - survey, case control, cohort
Interventional - RCT
