EBM/Research/Ethics Flashcards
2x2 table - Which values change with a chance in disease prevalence?
PPV and NPV
What is type 1 vs type 2 error?
Type 1 = false positive study
Type 2 = false negative study
Efficacy vs. Effectiveness?
Efficacy: value of intervention to group who accept advice and comply with it (ideal world, theoretical impact)
Effectiveness: value of intervention to a group offered it (real world, actual impact)
Define and provide the formula for:
a. Prevalence
b. Incidence
Incidence rate = # of new cases during specific time period / observed person-time among people at risk during this time period
PREVALENCE = # of cases at specific time (new + ongoing cases) / total # of people at specific time
- aka: ‘burden of disease’
Define regression analysis and name 2 types
Regression analysis is a set of statistical processes used to define the relationship among variables. It examines the influence of an independent variable on the dependent variable.
Types: Linear regression, Logistic regression
5 literature “quality” categories
Level of evidence: 1 - RCT/ systematic review 2- cohort (prospective) 3- retrospective, case-control 4- case series 5- case report, expert opinion
4 quality indicators in an RCT
- Randomization
- Allocation Concealment
- Blinding
- Intention to treat analysis
- Inclusion and Exclusion Criteria
- Sample Size Calculation
- Loss to follow up - patient flow diagram
What is the name of the value you calculate in a case-control study that tells you the impact of an exposure on a population?
Odds ratio
What four steps are there in creating a clinical decision rule?
derivation, validation, implementation and impact analysis
What are the characteristics of a good screening test? A good confirmatory test?
● Highly sensitive
● Sensitive in early disease when subsequent course can be altered
● Acceptable to the population
● Diagnostic test: Highly specific
What are 3 requirements for a minor to give consent?
- informed
- non-coerced
- capacity
they “CAN” give consent - capable, appropriate info and non-coercive (voluntary)
parents refuse treatment - list 5 steps to address their concerns
- Identify their concerns
- Review the importance of the treatment and benefits/risks of treatment
- Provide alternatives if they exist
- Use common language/no medical jargon
- Keep in mind cultural differences and language barriers; may need to include people from their culture that they respect and would like present or to be part of the decision
- Determine if the child has the capacity to consent to treatment
- Document all discussions
Four ethical principles of human research
- autonomy
- beneficience
- nonmaleficience
- distributive justice
- respect for informed consent
- respect for privacy and confidentiality
Three criteria for determining authorship on a scientific paper
● Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND
● Drafting the work or revising it critically for important intellectual content; AND
● Final approval of the version to be published; AND
● Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
3 indications to break confidentiality
- Intended harm to self (i.e. suicidal ideation)
- Intended harm to others (i.e. homicidal ideation)
- If there is suspicion of child abuse
What are 4 things to do if you have had a medical error?
● medical error disclosure involves explaining what happened and why
● what will be done to prevent recurrence
● offering an apology
● Filing safety report
● Ensuring safety of child
What is the age of consent?
16 yo
18 for exploitative
Close in age exception: 12-13yo + 2 years old, 14-15 yo + 5 years old
What is intention to treat analysis?
• analysis based on the initial treatment assignment groups (even if that’s not the group they stayed in) and not on the treatment eventually received
vs. per protocol analysis
RCT’s - pros and cons
PROS:
o randomization gives best evidence for causality
o minimizes effects of confounders through randomization and blinding
o decreases bias
o efficacy/effectiveness of intervention can be assessed
CONS:
o expensive
o time consuming (long, follow-up required)
o difficult for rare events
o may be unethical
o “volunteer” bias
o narrow inclusion/exclusion criteria can limit generalizability
Cohort study - pros and cons
PROS:
o treatment not withheld
o can match subjects for potential confounders
o if prospective, can standardize eligibility and outcome measures
o can study incidence and time course of disease (natural history)
o generally cheaper than RCTs
o can estimate relative risk (incidence)
CONS:
o controls may be difficult to obtain (researchers aren’t in control of what the exposure is/was)
o does not deal with unanticipated confounders
o challenging for rare diseases/outcomes (not enough patients to follow them over time)
o loss to follow-up
o no causation, but can show association
o cost
Case-control pros and cons?
PROS:
o relatively quick and cheap
o may be the only feasible method to study rare disease or long lag from exposure to outcome
o smaller sample size, good for rarer diseases
o study etiology not treatment
CONS:
o recall/record bias
o choice of controls can be problematic
o dose not deal with unanticipated confounders
o no incidence rates/relative risk
o does not determine causality or incidence
Cross-sectional study - pros and cons?
PROS:
o cheap and quick and safe
o good to identify prevalence (how many cases are occurring RIGHT NOW)
o can generate 2x2 tables for comparison of groups
CONS:
o can determine association NOT causation
o does not deal at all with confounders
o cannot determine incidence
Systematic reviews - pros and cons?
PROS:
o if well-conducted, can be invaluable
o can examine inconsistencies between trials
o if combining multiple small studies, can create more precise answers
CONS:
o “garbage in, garbage out”
o biases: publication, time-lag
Sensitivity definition?
• sensitivity = given that the disease is present, the probability that the test is positive
• sensitivity = the proportion of people with the disease who test positive
1st column = a / (a+c)
SnNOUT – when Sensitivity is high, a Negative test rules OUT the disease (ex. urine cultures for UTI)
Specificity definition?
• specificity = given that the disease is absent, the probability that the test is negative
• specificity = the proportion of people without the disease who test negative
o 2nd column = d / (b+d)
SpPIN – when Specificity is high, a Positive test rules IN the disease (ex. biopsy for diagnosing cancer)
PPV definition?
• PPV = given that the test is positive, the probability that the disease is present
• PPV = the proportion of people who test positive who have the disease
o 1st row = a / (a+b)
NPV definition?
• NPV = given that the test is negative, the probability that the disease is absent
• NPV = the proportion of people who test negative who don’t have the disease
o 2nd row = d / (c+d)
