(M) Analytic - Epidemiologic Approach Flashcards
Event of interest
disease or death
Outcome
should proceed before the outcome
Exposure
Health-related event of interest
Outcome
death, disease condition like AIDS
Outcome
when someone got pregnant, whats the outcome and determine exposure
Exposure - tite, and fertilization of sperm with egg cell
outcome - blessing
blessing - anak
Having, or being exposed to, a potential cause or risk factor for disease or other outcome
Exposed
being a smoker or having sex with someone who has an STI
Exposed
Not having, not being exposed to, a potential cause or risk factor for disease or other outcome
Unexposed
Individuals that are disease positive
Cases
Individuals that are disease negative
Controls
Test the hypothesis of relationship between at minimum, two variables
Analytic Studies
what are the 2 variable that concerns with ANALYTIC studies
- one independent variable (exposure)
- one dependent variable (disease)
Analyitc studies - T or F
There is a comparison between comparator group (exposed and unexposed; positive and negative etc..)
T
Determine the factor, and outcome
Hypothesis – Is smoking related to hypertension?
- Factor – Smoking
- Outcome – Hypertension
in cross sectional what comes first. population or selected sample
Population
Cross-sectional
other name for it
Prevalence study
cross - sectional
Exposure and Outcome are measured at
One-point in time
sabay
Cross-sectional
if one point at a time, what will be the weakness?
Exposure should come first before outcome
– which means we cannot actually determine which came first
Cross-sectional
what are the categories?
- With Exposure, With Outcome
- With Exposure, Without outcome
- Without Exposure, With outcome
- Without Exposure, Without Outcome
Uses of Cross-sectional Study - T or F
Estimate burden of disease (prevalence)
T
Uses of Cross-sectional Study - T or F
Establish baseline data
T
Uses of Cross-sectional Study - T or F
Determine association between non-existing variables
F
Coexisting Variables
Cross-sectional
What are the 2 analysis
- Measures of Disease Occurence
- Measure of Association
Cross-sectional: Analysis
under measures of disease occurrence
- Prevalence in the population
- Prevalence among exposed
- Prevalence among unexposed
Cross-sectional: Analysis
under measure of association
Prevalence ratio
Advantages of cross-sectional studies
- Resource-eficient
- Does not suffer from attrition
- Generalizable
Disadvantages of cross-sectional studies
Difficult to establish causality
why is it hard to establish causilty using cross-sectional?
Temporal ambiguity between exposure and outcome: Which came first?
temporal ambiguity is also a concern for ecological studies
if u see this card
go over the formula for prevalence proportion and Prevalence ratio
PR = 1
Exposure is not associated with the outcome
Numerator = Denominator
The ratio = 1, no relationship.
no relationship with exposure and outcome
PR < 1
Exposure variable negatively associated with the outcome
Unexposed > Exposed
The ratio: < 1
the exposure variable is protective of the disease
Unexposed > Exposed; The ratio = < 1
PR > 1
Exposure variable positively associated with the outcome
Exposed > unexposed
The ratio: > 1
prevalence of the disease is higher among the exposed than among the unexposed
the ratio is > 1
T or F
The exposure variable is a risk factor to the disease
True
what is the PRINCIPLE in a cohort study?
Exposure First, then A follow up
- the follow up is to know if there is a CONCERNED OUTCOME
This approach is suitable in determining the influence of a particular risk factor in the causation of an event, such as a particular disease.
Cohort Study
Begins with the identification/selection of a group exposed to a risk factor, and a comparable group not exposed.
Cohort Study
In cohort study Both groups are then observed if they will develop the ?
sickness
if mag kaka cancer sila or what disease they were exposed to
what should be the characteristic of the group in a cohort study?
Distinct set of characteristics; secondary to:
* Common setting
* Common experience
Refers to the secular change of disease frequency in a group as influenced by membership in that particular group.
Cohort Effect
Exposure is measured at the present time and the participants are followed up to measure Outcome at a future time
Cohort Study
other names for cohort study
- Follow Up Study
- Longitudinal Study
- Incidence Study (something new; positive sa disease)
Types of Cohort Study
- Prospective/concurrent
- Retrospective/non-concurrent
- Ambispectibe
Types of cohort
starts at the beginning
Prospective/concurrent
Types of cohort
starts at the end(future) of the study
Retrospective/non-concurrent
Types of Cohort
mixed of both
Ambispective
Uses of Cohort Study - T or F
Calculate risk of developing disease
T
Uses of Cohort Study - T or F
Establish the temporal relationship between study variables
T
Uses of Cohort Study - T or F
Expedient in examining single outcomes
F - MULTIPLE
Uses of Cohort Study - T or F
Practical in studying rare exposures
T
Cause there is already a established person with the disease, just need to retrospective the exposure and not randomly try to guess which exposure lead to the outcome
Cohort Study: Analysis
what are measures under this?
- Measures of Disease Occurrence
- Measures of Association
Cohort Study
under the measure of disease occurrence
- Incidence Proportions
- Incidence Rates
Cohort Study
under measures of association
- Risk Ratio
- Rate Ratio
Advantages of Cohort Study
- More likely to determine causality (as compared to a cross-sectional study)
- Followed the natural history of disease
At the start, those with the outcome of interest should be excluded.
Cohort Study
If they have sickness, out na sa study
Disadvantages of Cohort Study
- Resource-intensive
- Sufferes from attrition
If u see this card
Go over the formula for incidence proportion and Incidence Rate
Cohort Study
- Describes the average risk for developing a disease condition
- More useful in determining etiologic/risk factors of diseases more than prevalence proportion
Incidence proportion
Cohort Study
- Describes the speed at which new cases occur
- “Time at risk”
Incidence Rate
period or duration at which each person is vulnerable (“at risk”) of developing the disease
“Time at risk”
Relative Risk is also known as?
- Risk Ratio
- Rate Ration
*
Cohort Study
if comparing incidence proportions
Risk Ratio
Cohort study
if comparing incidence rates
Rate Ratio
RR > 1
Exposure variables is a risk factor
shows an association
RR > 1
conclusion can be read “those with the exposure were more likely to develop disease.”
RR > 1
exposure variable is protective factor
RR < 1
T or F
OR is just an estimation of the RR.
OR = odd ratio
True
The RR is a more powerful effect measure than the?
OR (ODD RATIO)
if u see this card
Go over the example for RISK RATIO yung mahaba
A type of study that attempts to capture the advantages of both the cross-sectional study and the cohort study
Case-Control Study
It tries to eliminate the temporal ambiguity of the cross-sectional study while at the same time shortening the duration of the study
Case-Control Study
Outcome is measured at the present time and Exposure of the participants in the past is estimated
Case-Control Study
Case Contol
1st step process
We select the cases from a target population.
Case Control Study
3rd Step
Then select another group of individuals without the outcome or disease as Controls
ex. Women without breast cancer of the reproductive age group
Case Control Study
2nd Step
Cases are a group of individuals with the outcome or disease
ex. Women with breast cancer of the reproductive age group
Case-control Study
4th Step
Go back in time (retrospective) to determine exposure in the cases and in the control
Case-Control Study
5th Step
Compares the exposure status among the cases and among the controls
Uses of Case-Control Study - T or F
Determine association between variables
T
Uses of Case-Control Study - T or F
Estimate ratio risk
F - Relative Risk
Uses of Case-Control Study - T or F
Expedient in examining multiple exposures
T
Uses of Case-Control Study - T or F
Practical in studying rare diseases
Because it already started with a case, which will not give a hard time to trace back
if u see this card
go over the example for case-control study
Case-Control Study: Analysis
what are the measures under this?
- Measure of Exposure occurrence
- Measure of Association
why is there no measure of disease occurrence under case-control??
cannot compute for prevalence and incidence
Case-control
Exposure Odds
Measure of Exposure Occurrence
case-control
Odds Ratio
Measure of Association
Advantages of case-control study
Less resource- intensive (as compared to a cohort study)
No attrition
Advantages of case-control studyDisadvantages
Likely to suffer from problems with recall
if u see this card
go over the formula for ODDS and EXPOSURE ODDS
The ratio of two odds. The odds ratio calculated from a case-control study is the ratio of the odds of exposure among the cases to the odds of exposure among the controls.
Odds Ratio
the conclusion is the “those with the disease are more likely to have the exposure”
OR > I
Exposure variable is a risk factor
OR > I
the exposure and disease are not associated.
OR = I
Exposure variable has no effect on outcome
OR = I
it can be said that the exposure has a protective effect against the disease
OR < I
difference of odd ratio and risk ratio?
odd ratio is from case control, risk ratio is from cohort
why odd ratio is not better than risk ratio?
it is just an estimation and RR talks more about LIKELINESS TO DEVELOP, whereas OR talks about EXPOSURE ALONE
The previous approaches: Cross-sectional, Cohort and case control study are all approaches that just
OBSERVES DATA!
the data? NO MANIPULATION!
OBSERVATIONAL ANALYTIC STUDIES
- Cross-sectional
- Cohort
- case control study
what is the main key of characterization for experimental study?
INTERVENTION! - there is an employent intervetion or manipulation
Experimental study - T or F
Randomize into Test (Experimental) group and Control group
T
Experimental study - T or F
Randomization ensures that both groups’ characteristics will become straight (the same), EXCEPT for the treatment
F - HOMOGENOUS
A cohort study, only with assignment/manipulation of Experimental + Randomization/random allocation
Experimental Study
Best study design for controlling confounders
Experimental Study
Provide strongest causal inference
Experimental Study
Limitation of experimental?
ethical issue!
But if solved, it will be the best design
Random Allocation
Randomization
Process of assigning each participant into a group—whether experimental or control—by chance
Randomization
A defining feature of a modern trial design
Randomization
Absence in an experimental study makes the study quasi-experimental in nature
Randomization
please
study the process for randomization now na
what are the classification of experimental Study
- Clinical Trial
- Community Trial
- Therapeutic Trial
- Prolyphlactive Trial
- Parallel Design
- Crossover Design
Intervention is allocated to individuals
Clinical Trial
Intervention is allocated to an entire community
Community Trial
intervention is a treatment agent
Therapeutic Trial
Intervention is a preventive agent
Prolyphlatctic Trial
AKA. “between-subjects” design
Parallel Design
AKA. “within-subjects” design
Crossover Design
Initially 1 in control group and experimental group- wash out period will happen and there will be cross over of group
“within-subjects” design
Crossover Designq
Experimental Study: Analysis
- Measures Disease Occurrence
- Measures of Association
Experimental Study: Analysis
Incidence Proportions
Incidence Rates
Measures Disease Occurrence
Experimental Study: Analysis
Risk Ratio
Rate Ratio
Measures of Association
Disadvantage of Experimental study
- Ethical Considerations
- Resoure Intensive
if u see this card
go over all of the formula for experimental study
Experimental - Clinical
Number of events or Disease (risk) in the experimental group. (among the exposed)
Experimental Event Rate (EER)
Experimental - Clinical
Number of events or Diseases (risk) in the control group
Control Event Rate (CER)
Experimental - Clinical
ratio of the risk of the disease in the experimental group (EER) and the risk in the control group (CER).
Risk Ratio
Experimental - Clinical
also called the Risk difference is the difference in the event rates for the EER and CER.
Absolute Risk Reduction (ARR)
Experimental - Clinical
relative to those who are in the control group
Relative Risk Reduction (RRR)
Experimental - Clinical
he number Of patients who would have to receive the treatment for one of them to benefit.
Numbers Needed to Treat (NNT)
if u see this card please PLEASE
go over the intention to treat vs. per protocol analysis
diko sinama TOO MANY FUCKER
“a review of the evidence on a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant primary research, and to extract and analyze data from the studies that are included in the review.” The methods used must be reproducible and transparent.
Systematic Review
A comprehensive review of all relevant studies on a particular clinical or health-related topic/question.
Systematic Review
created after reviewing and combining all the information from both published and unpublished studies (focusing on clinical trials of similar treatments) and then summarizing the findings (STUDY OF OLD DATA)
Systematic Review
what needs to be combined in a systematic review?
all the information from both published and unpublished studies
Systematic Review - T or F
The scope of the review is identified in advance (eg review question and sub‐questions and/or sub‐group analysis to be undertaken)
T
Systematic Review - T or F
Comprehensive search to find some relevant studies
F - ALL
Systematic Review - T or F
Use of explicit criteria to include / exclude studies
T
Systematic Review - T or F
Application of established standards to critically appraise study quality
T
Systematic Review - T or F
Explicit methods of extracting and synthesizing study findings (qualitative or quantitative)
T
Systematic Review - T or F
Need to include a meta-analysis (quantitative synthesis)
F - may only (optional baga)
Uses or Limitation of Systematic Review
Identifies, appraises and synthesizes all available research that is relevant to a particular review question
Uses of Systematic Review
Uses or Limitation of Systematic Review
Systematic reviews with narrowly defined review questions provide specific answers to specific questions
Limitation
Uses or Limitation of Systematic Review
Alternative questions that have not been answered usually need to be reconstructed by the reader
Limitation
Uses or Limitation of Systematic Review
Collates all that is known on a given topic and identifies the basis of that knowledge
Uses
Uses or Limitation of Systematic Review
Comprehensive report using explicit processes so that rationale, assumptions and methods are open to scrutiny by external parties
Uses
Uses or Limitation of Systematic Review
Can be replicated / updated
Uses
Advantages of Systenatic Review - T or F
Exhaustive review of the current literature and other sources (unpublished studies, ongoing research)
T
Advantages of Systenatic Review - T or F
more costly to review prior studies than to create a new study
F - less costly
Advantages of Systenatic Review - T or F
Less time required than conducting a new study
T
Advantages of Systenatic Review - T or F
Results can be generalized and extrapolated into the general population more broadly than individual studies
T
Advantages of Systenatic Review - T or F
More reliable and accurate than ecological studies
F - individual studies
Advantages of Systenatic Review - T or F
Considered an evidence-based resource
T
Disadvantages of Systematic Review
- Very time consuming
- May not be easy to combine studies
Design Pitfalls to Look Out For
Studies included in systematic reviews may be of varying study designs, but should collectively be studying the same outcome.
Is each study included in the review studying the same variables?
Design Pitfalls to Look Out For
Some reviews may group and analyze studies by variables such as age and gender; factors that were not allocated to participants.
Do the analyses in the systematic review** fit the variables** being studied in the original studies?
A subset of systematic reviews:
Meta-Analysis
A method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power.
Meta-analysis
This conclusion is statistically stronger than the analysis of any single study, due to increased numbers of subjects, greater diversity among subjects, or accumulated effects and results.
Meta-Analysis
Meta-analysis provides a
logical framework to a research review
provides a logical framework to a research review where similar measures from comparable studies are listed systematically and the available effect measures are combined wherever possible.
Meta-Analysis
It reduces the quantity of data by summarizing data from multiple resources and helps to plan research as well as to frame guidelines.
Fundamental Rationale of META ANALYSIS
t also helps to make efficient use of existing data, ensuring generalizability, helping to check consistency of relationships, explaining data inconsistency, and quantifies the data.
Fundamental Rationale of META ANALYSIS
It helps to improve the precision in estimating the risk by using explicit methods.
Fundamental Rationale of META ANALYSIS
Uses of Meta-Analysis - T or F
To establish statistical significance with studies that have conflicting results
T
Uses of Meta-Analysis - T or F
The data is combined thats why it is much stronger
T
Uses of Meta-Analysis - T or F
To develop a less correct estimate of effect magnitude
F - MORE CORRECT
Uses of Meta-Analysis - T or F
To provide a more simple analysis of harms, safety data, and benefits
F - COMPLEX ANALYSIS
Uses of Meta-Analysis - T or F
To examine subgroups with individual numbers that are not statistically significant
T
Advantages or Disadvatanges (Meta-analysis)
Greater statistical power
Advantages
Advantages or Disadvatanges (Meta-analysis)
Confirmatory data analysis
Advantages
Advantages or Disadvatanges (Meta-analysis)
Difficult and time consuming to identify appropriate studies
Disadvantages
Advantages or Disadvatanges (Meta-analysis)
Greater ability to extrapolate to general population affected
Advantages
Advantages or Disadvatanges (Meta-analysis)
Not all studies provide adequate data for inclusion and analysis
Disadvantages
Advantages or Disadvatanges (Meta-analysis)
Requires advanced statistical techniques
Disadvantages
Advantages or Disadvatanges (Meta-analysis)
Heterogeneity of study populations
Disadvantages
Advantages or Disadvatanges (Meta-analysis)
Considered an evidence-based resource
Advantages
Design Pitfalls to Look Out For - Meta Analysis
The studies pooled for review should be similar in type (i.e. all randomized controlled trials).
Are the studies being reviewed all the same type of study or are they a mixture of different types?
Design Pitfalls to Look Out For - Meta Analysis
The analysis should include published and unpublished results to avoid publication bias.
Does the meta-analysis include any appropriate relevant studies that may have had negative outcomes?
refer to the entire process of collecting, reviewing, and presenting all available evidence
Systematic review
refer to the statistical technique involved in extracting and combining data to produce a summary result.
Meta-analysis
the goal is to produce SUMMARY RESULT
Meta-analysis
Systematic Review vs Meta-Analysis
Statistical techniques employed
Meta-analysis
Systematic Review vs Meta-Analysis
entire process of collecting, reviewing, and presenting all available evidence
Systematic Review
gold standard for demonstrating causality between the use of a specific medicine and intended and unintended effects under ideal conditions.
Randomized Controlled Trials (RCTs)
Limitations of RCT - T or F
Limited to evaluating specific interventions one by one
T
Limitations of RCT - T or F
When selecting the patient sample according to strict inclusion and exclusion criteria, they have reduced external validity (or generalization), which maximizes the transfer of their results.
F - LIMITS the transfer
Limitations of RCT - T or F
The highly selective populations examined within the setting of RCTs are often not comparable with the more heterogeneous populations in clinical practice.
T
Limitations of RCT - T or F
Heterogeneous population in the real world setting
T
Limitations of RCT - T or F
“Efficacy-effectiveness gap” (Eichleretal)
T
disparity of findings on the therapeutic efficacy of medicines from tightly controlled RCT settings and the effectiveness of medicines in the real world.
“Efficacy-effectiveness gap” (Eichleretal)
observational studies based on real data obtained from daily clinical practice.
real-world data (RWD)
evidence obtained from real-world data (RWD)
Real world evidence (RWE)
studies that collect data relevant to human health that do not come from conventional randomized clinical trials.
Real World Data
RWD - T or F
They document the real care that patients receive in the clinic and include a variety of cases (for example, patients suffering from several diseases at once) without limiting strict inclusion and exclusion criteria.
True
what is generated in RWD
long-term data – on the effectiveness and safety of health interventions
RWD provides?
useful information for economic health analyses
RWD and RWE provide
external validity that RCTs lack
Advantages over RCTs of RWD - T or F
lower cost, larger sample size, and greater representativeness than other research designs, and high external validity.
T
Advantages over RCTs of RWD - T or F
single sources – patient registries, administrative claims, and social media channels
F - FROM VARIOUS SOURCES
Advantages over RCTs of RWD - T or F
Application – Different real environments providing insights into drug safety, in health and financial terms, and its long-term effects.
T
Real-world data can improve decision-making, pre-authorization, and reimbursement of new drugs and treatments and benefit medical research and patient outcomes.’
Advantages over RCTs
if u see this card
study the quality of evidences hierarchy
if u see this card
go na sa next dami pa yung validity of study designs
