Research Exam 2 PPT 3 and PPT 4

Question 1

Descriptive observational study

Answer 1

Designed to describe the distribution between two or more variables without regards of hypothesis or any causal
-Not one clinical/epidemiology study can answer the research question definetly
-Information is collected routinely so less time consuming
-Essential for formulation hypothesis/research question

Question 2

Case report

Answer 2

Single patient

Question 3

Case series

Answer 3

Series of patient

Question 4

Case report and case series

Answer 4

Observational descriptive study design the most basic
-Make link between clinical medicine and epidemiology of the disease
-Chance of observation may open a new line of investigation

Question 5

Cross sectional studies

Answer 5

Observational descriptive study
-Measures the association of the outcome and the exposure within a population using a specific target time point
-Helpful in assessing the disease burdern and the healthcare needs
-Useful to estimate the prevalence of the disease and the exposure

Question 6

Observational Analytical study

Answer 6

Designed to perform Hypothesis testing to establish association between the outcome and the exposure
-Is comparison of groups
-Timing sequece
-Observational - Case control studies, cohort studies
-Interventional (Experimental)-Randomize control trials

Question 7

Cohort

Answer 7

Based on the exposure
It can be prospective or retrospective

Question 8

Case control

Answer 8

Based on the outcome
Is retrospective

Question 9

Prospective

Answer 9

Record information before the outcome occur
“Will follow patients for 5 years and recorded the incedence in both groups”

Question 10

Retrospective

Answer 10

Collect data after exposure occur

Question 11

An observational study is being conducted in 2023 to investigate whether vasopresssin increases the risk of venous thromboembolism (VTE) among critically ill patients. The investigators sampled patients who were hospitalized in the ICU from 2020-2022 and obtained two groups: one group who were treated with vasopressin and another group who were not treated with vasopressin. The investigators then recorded whether patients in each group developed VTE during their hospitlization.
Which of the following best describes this study?
A) Retrospective cohort study

B) Nested case-control study

C) Traditional case-control study

D) Prospective cohort study

Answer 11

A) Retrospective cohort study

Question 12

Selecting cohorts

Answer 12

1-Type of exposure being investigated
2-Frequency of exposure in the population
3-Accesibility of pt
-Pt should be free of the outcome at the start of the study in order to establish temporal relationship between exposure and outcome
-Divided into exposed and unexposed
-Measurement of exposure is based on Variability, Intensity, regularity, duration
-At the start both exposed and unexposed should have the equal chance of developing the outcome-Counterfactual idea

Question 13

Folow up in cohort studies

Answer 13

Frequency of examination and duration needs to be follow up but is based on the exposure and outcome of interest
-Need to follow up both group on the same time
-Concern on loss-to-follows up usually in long term studies

Question 14

Cohort studies pros

Answer 14

-Incidence data is available
-Establish temporal relation
-Study mutliple outcomes
-Study rare exposures

Question 15

Cohort studies cons

Answer 15

-Expensive more time consuming than case control
-Loss to follow up
-Large sample size
-Cannot study rare outcomes

Question 16

Case control study step 1

Answer 16

Select cases that are the patients that have the disease the outcome based on case definition

Question 17

Case control study step 2

Answer 17

Select the controls
-Pt that dont have the disease (outcome)
-They are selected from the population that gave rise to the cases
-They are independent of the exposure

Question 18

Case control study pros

Answer 18

-Less time consuming and inexpensive
-Smaller sample size
-Can study multiple exposule
-Can study rare outcomes
-Efficient for long term

Question 19

Case control study cons

Answer 19

-Cannot establish relation
-Difficult to identify controls
-Cannot study rare exposures
-Cannot predict incidance rate and prevalence
-Cannot calculate RR and RD only OR

Question 20

Nested case-control studies

Answer 20

A cohort study need to happend they are exposed then alot of time need to pass and if they have the disease they will be cases and if they dont have the disease they are controls
-The controls are selected from the cohort/target population that gave rise to the cases
-More time consuming cause uses a cohort study first than time needs to pass and get a case control studie
-OR is the measurement
-Disadvantage- more time consuming and less stregnth of evidence than cohort study

Question 21

Experimental study designs

Answer 21

Study design that is used to compare the benefits of a intervention with treatment or no treatment is used to see the cause and effects
-Is prospectives subjects are place in a study group and then follow up over time
-Randomize controlled trial
-Quasi experimental non random trial

Question 22

Randomized controlled trials

Answer 22

-Is a prospective study design compares the efficacy and effectiveness of a drug compared with the control group
-Done in human
-Gold standard for study design
-Is used for causation
-Has randomization, blindness, control group

Question 23

Efficacy trials

Answer 23

Compares the new drug with the comparator (the placebo) under ideal setting
-Homogenous population

Question 24

Effectiveness (Pragmatic) Trials

Answer 24

Compares the new drug with the comparator that is the usual care under REAL WORLD CONDITIONS
-Heterogenous population

Question 25

Concurrengt/Parallel design
a RCT design

Answer 25

-The most common RCT design
-Participants are assigned a group treatment and stayed in the same group throughout the study

Question 26

Crossover design a RCT

Answer 26

-Participants are randomily assigned to either the intervention group (exposure to drug) or the comparator (placebo) and then they will switch groups
- A CARRY OVER EFFECT needs to happen- that is a washout period not give any drug to prevent residual effect
-PERIOD EFFECT- is a stable disease and it provided byster

Question 27

Factorial design a RCT

Answer 27

Asseses multiple intervention in the same study
-So 2 interventions 4 possible combinations
-Has synergy that his potential for combining
-Drug A + Placebo
-Drug B+ Placebo
-Drug A + Drug B
-Placebo + Placebo

And the pts are randomize to the different groups

Question 28

RCT Design: Randomization

Answer 28

-Assigment of participants to the intervention group or comparation group placebo they have a equal chance of being selected
-Need to ensure similar characteristics in both groups
-Want to see the cause and effect of the treatment
-Randomization allows investigators to get close to counterfactual ideal

Question 29

Simple randomization

Answer 29

Uses a random number generator to allocate the pts in the different groups
-Easiest approach to randomization but small sample size cause unequal number of participants in each group

Question 30

Block randomization

Answer 30

Ensure the same number of participants in the treatment group and control group
-The participants are randomly divided into blocks and then the investigator randomly select a block for the study

Question 31

Stratified randomization

Answer 31

Participants are divided into different strata based on specific characteristics and then they are randomly selected from each strata into a treatment group
-Ensure certain baseline characteristics are equal between the treatment groups

Question 32

In a randomized controlled trial assessing the effectiveness of a new anxiety medication, the researchers want to ensure that history of depression at baseline are evenly distributed between the two treatment groups. Which randomization technique would best address this concern in the given scenario?
A) Cluster randomization

B) Block randomization

C) Simple randomization

D)Stratified randomization

Answer 32

D) Stratified randomization

Question 33

Cluster randomization

Answer 33

Specific groups (clusters) are randomize selected into a treatment group
Each subject in the cluster will receive the same treamnt
-Clusters can be: clinics, highschools, community, villages
-Useful for measuring the effect of the intervention in an entire community

Question 34

Open label

Answer 34

When blinding is impossible or unethical
The participant, investigator and data analysist know what they are taking

Question 35

Single blinded

Answer 35

Only the participant dont know what they are taking but the investigator and data analysis knows

Question 36

Double blinded

Answer 36

When the participant and the investigator dont know what they are taking but the data analysis do know

Question 37

Triple blinded

Answer 37

neither of the three participant, investigator and data analysis knows what they are taking

Question 38

RTC Design: Run In Period

Answer 38

-Is prior the trial start is remove all ineligible pts and non compliant pts
-Sometimes used as a carry over period (a wash out period) for pt to stop taking any medication prior to the trial

Question 39

Role of run in period

Answer 39

Ensure pt compliance and adherence
Minimize placebo effect
Ensure drug response

Question 40

The purpose of the run-in period in a randomized controlled trial is to:
A) Ensure compliance to treatment

B) Overestimate the drug benefits

C) Maximize placebo effect

D) Underestimate the risks of treatment

Answer 40

A) ensure compliance of the treatment

Question 41

Intention to treat ITT

Answer 41

Analyze all pt in both groups regardless if failed to follow up or took placebo when they shouldn’t
-try to preserve randomization

Question 42

Suppose a clinical trial randomly assigned 150 patients to receive either drug A (n=75) or placebo (n=75). At the end of the study, the researchers had the following results: in the drug A group, 70 were on drug A and 5 were on placebo; and in the placebo group, 72 were on placebo and 3 were on drug A. The investigators decide to analyze the study to include all patients as randomized, regardless of the treatment at the study end. Which of the following best describes this type of analysis?
A)Per-protocol

B)As-treated

C) Intention-to-treat

Answer 42

C) Intention to treat

Question 43

Per protocol (PP) or on treatment

Answer 43

Only analyze pt that took what they needed to take
-Does not take into consideration Loss of follow up or cross over
-Randomization is not preserve
-Is useful for analyzing AE

Question 44

As treated AT

Answer 44

At the end of the study the 3 pt that took placebo in the drug group will be analyze as the placebo group
-Randomization is not preserve
-Cross over and Loss of follow up is a concern

Question 45

Kaplan meier analysis

Answer 45

Summarizes the probability of survival over time
-It analyzes using log-rank test
-Compares the overall survival between the groups with respect to the study outcome

Question 45

Randomize control trial pros

Answer 45

Reach counterfactual ideal
-Provide causal evidence
-More control over measurments

Question 46

Randomize control trial cons

Answer 46

-More expensive and time consuming
-Cannot be measure in all conditions due to ethical reasons

Question 47

Quasi Experimental study design

Answer 47

Lack of randomization
-Is used to analyze a new implemented program or policy

Question 48

History effect

Answer 48

Some event other than the intervention occur during the time frame that is causing the observe change

Question 49

Maturation effect

Answer 49

Participant change their way of study and learning throughout the research

Question 50

Regression toward the mean

Answer 50

natural variation of repeated data look like real change

Question 51

Interrupted time series design

Answer 51

Uses multiple observations before and after the intervention, during a specific time frame
-See a change in the antibiotic use after the implementation of a new hospital policy

Question 52

An investigator is interested in investigating the implementation of a hospital policy to restrict the use of opioids using an algorithm. The investigators want to measure whether a change in the reduction in adverse events ocurred before and after the policy implementation. Which of the following studies would be the most appropriate to conduct this study?

A) Interrupted time series

B) One group pre-test post-test

C) Cohort study

D) Randomized controlled trial

Answer 52

A) interrupted time series