MDSC 515 FINAL QUESTIONS AND ANSWERS
Thalidomide - Answers :-anti-convulsive drug - made users sleepy and relaxed
-impossible to achieve LD50 of the drug (this is when 50% of the test organisms die due
to poisoning from it)
-animal tests did not determine the effects during pregnancy
-it was highly toxic during pregnancy - babies were born without limbs due to it
-pregnant women had been taking it as it reduced morning sickness
-eventually it was withdrawn as the outcomes were bad
Theranos - Answers :-theranos testing only required a drop of blood for thousands of
tests to be completed on individuals
-it was also a cheaper method than typical conventional methods
-it began to become more popular in lots of pharmacies
-then an investigation discovered it was fabricating a lot of its results and then it was
withdrawn as a method
Hydroxychloroquine - Answers :-originally an anti-malarial drug
-used now for a lot of rheumatoid conditions (auto-immune)
-anti-inflammatory - inhibit lysosome functions (inflammatory functions such as release
of inflammatory cytokines and build up of cellular debris)
-anti-malarial function involves the inhibition of malarial haemozoinb formation to avoid
toxic buildup of heme breakdown products (haemozoin formation required for the
survival of malaria in the cells otherwise it is attacked by toxic effects of heme)
-was originally said to decrease covid replication
-after studies it was shown not to be associated
Evidence based medicine - Answers :-integration of the best research evidence with
clinical expertise and patient values
Bradford hill criteria - Answers :1. Strength of association - larger association = more
likely it was the cause
2. Consistency: if the findings have been consistently found it is more likely they are true
3. Specificity: more specific an association the more likely there is a causal relationship
4. Temporality: the effect came after the cause - can know that it was potentially the
cause of it
5. Biological gradient: greater exposure leads to greater outcomes
6. Plausibility: plausible mechanism between cause and effect
7. Coherence: coherence between epidemiological and laboratory findings increases
the likelihood of the effect.
8. Experimental evidence
9. Analogy: the use of analogies or similarities between the observed associations and
other associations
10. Reversibility: if the cause is deleted then the effect disappears as well
Framing research questions - Answers :-establish a framework to evaluate the research
,-identify/prevent bias
-organize a research study of insufficient evidence is available
Qualitative research - Answers :-exploratory
-hypothesis generating
-more interpretive
-attempting to understand complex phenomena
-involves thematic analysis - identify themes
Quantitative - Answers :-structured
-seeking to understand
-association to causation
-observational or experimental
-involves statistical analysis
-used to test hypotheses
Observational research studies - Answers :-no direct intervention by the researcher
-case report: single case
-case-series: multiple instances of disease
-cohort: multiple instances of exposure
-case-control: comparing exposure data in patients who have the disease (cases) and
those who dont (controls)
Experimental research studies - Answers :-specific intervention by the researcher
-diagnostic test studies - may be experimental or observational
-rcts - randomized
Retrospective vs prospective research - Answers :-retrospective looks back into the
past to collect data
-prospective progresses into the future to collect data - controlled variables/exposures
Observational retrospective studies - Answers :-case report
-case control
-case studies
-all of the situations where the individuals already have the disease and we look back to
determine potential associations with exposures
Observational prospective studies - Answers :-cohort
-individuals have yet to develop the disease but have the risk factors so we watch to
see if they develop it
Diagnostic test studies - Answers :-when testing a novel diagnostic test against a
reference standard
-can be retrospective in the sense they use information from the past or prospective in
that they follow individuals in the future
,-involves individuals either with the disease or suspected to have the disease as well as
controls
Critical appraisal - Answers :-how to we determine if evidence should be included
-is any evidence considered sufficient
-is bad quality evidence better than no evidence
-is there methods to appraise evidence
GRADE - biomedical appraisal - Answers :-Grading of Recommendations, Assessment,
Development and Evaluations
-critical appraisal tools for high-level appraisal of medical studies
GRADE certainty ratings - Answers :-very low: the effect is probably markedly different
from the estimated effect
-low: the true effect might be markedly different from the estimated effect
-moderate: true effect is probably close to the estimated effect
-high: confidence that the true effect is similar to the estimated effect
Why would certainty be rated down - Answers :-risk of bias - flaws in study design or
data reporting
-imprecision - uncertainty of effect of magnitude (Confidence interval)
-inconsistency - contrasts with other studies
-indirectness - population does not match study cohort or the outcomes of interest are
just surrogates of the outcome of interest - believe to be indicative of the outcomes
-publication bias - studies published just report anticipated outcomes or effects
Why would certainty be rated up - Answers :-large magnitude of effect
-dose-response gradient
-all confounders would decrease magnitude of effect (when there is an effect)
Subtypes of variables - Answers :-ordinal - all integers
-continuous - real numbers
-nominal - non-numerical - like colours
Event possibility - Answers :-when there is an observation, what are all the possible
outcome events
Event probability - Answers :-measure of the frequency of a given event when a series
of events are observed
Relative frequency - Answers :-actual probability of an event is unknown
-the relative frequency is the number of observations over time divided by the total
number of observations over that time
-associated error measure - need to do it enough times to ensure it is validated
Accuracy - Answers :measure of nearness of a given measurement to a reference point
, Precision - Answers :measure of consistency of a set of measurements
Prevalence - Answers :-number of cases per sample of population evaluated
Incidence - Answers :-number of new cases per sample of population evaluated per
time period
Tests of categorical variables - Answers :relative risk, odds ratio, sensitivity/specificity
Risk ratio - Answers :-ratio of risk in disease in exposed individuals versus the risk of
disease in non-exposed individuals
Odds ratio - Answers :-ratio of odds that a case was exposed versus odds that controls
were exposed
-odds of disease in the exposed over odds of disease in non-exposed
Use of OR and RR in studies - Answers :- can be used to measure the association
-odds ratio used in case-control - see the individuals with the disease compared to
without
-RR cannot be used for it as the control may not accurately represent the population
Hazard ratio - Answers :-ratio of a hazard in the presence of a
predictor/intervention/exposure to the hazard without
-HR<1 = reduction in the hazard in the presence of the predictor/indicator relative to the
baseline
-HR = 1 = no difference over the baseline
-HR>1 indicates an increase in the hazard in the presence of the predictor/indicator
relative to the baseline
Sensitivity - Answers :-how well a test correctly detects individuals with the condition of
interest
-minimizes false negatives
Specificity - Answers :-how well the test correctly identifies individuals without the
condition of interest
-minimizes false positives
Positive predictive value - Answers :-probability that a positive test is correct
Negative predictive value - Answers :-probability that a negative test is correct
Positive likelihood ratio - Answers :-how much more likely individuals with the condition
are to have a positive test result
Thalidomide - Answers :-anti-convulsive drug - made users sleepy and relaxed
-impossible to achieve LD50 of the drug (this is when 50% of the test organisms die due
to poisoning from it)
-animal tests did not determine the effects during pregnancy
-it was highly toxic during pregnancy - babies were born without limbs due to it
-pregnant women had been taking it as it reduced morning sickness
-eventually it was withdrawn as the outcomes were bad
Theranos - Answers :-theranos testing only required a drop of blood for thousands of
tests to be completed on individuals
-it was also a cheaper method than typical conventional methods
-it began to become more popular in lots of pharmacies
-then an investigation discovered it was fabricating a lot of its results and then it was
withdrawn as a method
Hydroxychloroquine - Answers :-originally an anti-malarial drug
-used now for a lot of rheumatoid conditions (auto-immune)
-anti-inflammatory - inhibit lysosome functions (inflammatory functions such as release
of inflammatory cytokines and build up of cellular debris)
-anti-malarial function involves the inhibition of malarial haemozoinb formation to avoid
toxic buildup of heme breakdown products (haemozoin formation required for the
survival of malaria in the cells otherwise it is attacked by toxic effects of heme)
-was originally said to decrease covid replication
-after studies it was shown not to be associated
Evidence based medicine - Answers :-integration of the best research evidence with
clinical expertise and patient values
Bradford hill criteria - Answers :1. Strength of association - larger association = more
likely it was the cause
2. Consistency: if the findings have been consistently found it is more likely they are true
3. Specificity: more specific an association the more likely there is a causal relationship
4. Temporality: the effect came after the cause - can know that it was potentially the
cause of it
5. Biological gradient: greater exposure leads to greater outcomes
6. Plausibility: plausible mechanism between cause and effect
7. Coherence: coherence between epidemiological and laboratory findings increases
the likelihood of the effect.
8. Experimental evidence
9. Analogy: the use of analogies or similarities between the observed associations and
other associations
10. Reversibility: if the cause is deleted then the effect disappears as well
Framing research questions - Answers :-establish a framework to evaluate the research
,-identify/prevent bias
-organize a research study of insufficient evidence is available
Qualitative research - Answers :-exploratory
-hypothesis generating
-more interpretive
-attempting to understand complex phenomena
-involves thematic analysis - identify themes
Quantitative - Answers :-structured
-seeking to understand
-association to causation
-observational or experimental
-involves statistical analysis
-used to test hypotheses
Observational research studies - Answers :-no direct intervention by the researcher
-case report: single case
-case-series: multiple instances of disease
-cohort: multiple instances of exposure
-case-control: comparing exposure data in patients who have the disease (cases) and
those who dont (controls)
Experimental research studies - Answers :-specific intervention by the researcher
-diagnostic test studies - may be experimental or observational
-rcts - randomized
Retrospective vs prospective research - Answers :-retrospective looks back into the
past to collect data
-prospective progresses into the future to collect data - controlled variables/exposures
Observational retrospective studies - Answers :-case report
-case control
-case studies
-all of the situations where the individuals already have the disease and we look back to
determine potential associations with exposures
Observational prospective studies - Answers :-cohort
-individuals have yet to develop the disease but have the risk factors so we watch to
see if they develop it
Diagnostic test studies - Answers :-when testing a novel diagnostic test against a
reference standard
-can be retrospective in the sense they use information from the past or prospective in
that they follow individuals in the future
,-involves individuals either with the disease or suspected to have the disease as well as
controls
Critical appraisal - Answers :-how to we determine if evidence should be included
-is any evidence considered sufficient
-is bad quality evidence better than no evidence
-is there methods to appraise evidence
GRADE - biomedical appraisal - Answers :-Grading of Recommendations, Assessment,
Development and Evaluations
-critical appraisal tools for high-level appraisal of medical studies
GRADE certainty ratings - Answers :-very low: the effect is probably markedly different
from the estimated effect
-low: the true effect might be markedly different from the estimated effect
-moderate: true effect is probably close to the estimated effect
-high: confidence that the true effect is similar to the estimated effect
Why would certainty be rated down - Answers :-risk of bias - flaws in study design or
data reporting
-imprecision - uncertainty of effect of magnitude (Confidence interval)
-inconsistency - contrasts with other studies
-indirectness - population does not match study cohort or the outcomes of interest are
just surrogates of the outcome of interest - believe to be indicative of the outcomes
-publication bias - studies published just report anticipated outcomes or effects
Why would certainty be rated up - Answers :-large magnitude of effect
-dose-response gradient
-all confounders would decrease magnitude of effect (when there is an effect)
Subtypes of variables - Answers :-ordinal - all integers
-continuous - real numbers
-nominal - non-numerical - like colours
Event possibility - Answers :-when there is an observation, what are all the possible
outcome events
Event probability - Answers :-measure of the frequency of a given event when a series
of events are observed
Relative frequency - Answers :-actual probability of an event is unknown
-the relative frequency is the number of observations over time divided by the total
number of observations over that time
-associated error measure - need to do it enough times to ensure it is validated
Accuracy - Answers :measure of nearness of a given measurement to a reference point
, Precision - Answers :measure of consistency of a set of measurements
Prevalence - Answers :-number of cases per sample of population evaluated
Incidence - Answers :-number of new cases per sample of population evaluated per
time period
Tests of categorical variables - Answers :relative risk, odds ratio, sensitivity/specificity
Risk ratio - Answers :-ratio of risk in disease in exposed individuals versus the risk of
disease in non-exposed individuals
Odds ratio - Answers :-ratio of odds that a case was exposed versus odds that controls
were exposed
-odds of disease in the exposed over odds of disease in non-exposed
Use of OR and RR in studies - Answers :- can be used to measure the association
-odds ratio used in case-control - see the individuals with the disease compared to
without
-RR cannot be used for it as the control may not accurately represent the population
Hazard ratio - Answers :-ratio of a hazard in the presence of a
predictor/intervention/exposure to the hazard without
-HR<1 = reduction in the hazard in the presence of the predictor/indicator relative to the
baseline
-HR = 1 = no difference over the baseline
-HR>1 indicates an increase in the hazard in the presence of the predictor/indicator
relative to the baseline
Sensitivity - Answers :-how well a test correctly detects individuals with the condition of
interest
-minimizes false negatives
Specificity - Answers :-how well the test correctly identifies individuals without the
condition of interest
-minimizes false positives
Positive predictive value - Answers :-probability that a positive test is correct
Negative predictive value - Answers :-probability that a negative test is correct
Positive likelihood ratio - Answers :-how much more likely individuals with the condition
are to have a positive test result
