HYMR Clinical Research and Design Flashcards
Which of the following study designs would be most likely to determine the prevalence of a disease?
A. Cross-sectional study
B. Cross-over study
C. Cohort study
D. Case-controlled study
A. Cross-sectional study
When needing to determine the prevalence of a disease or situation, a cross-sectional study design is best method because they are a snapshot in time (ie what is the status of something right at the moment of the assessment)
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Which of the following study designs is a type of observational study?
A. Cross-sectional study
B. Crossover study
C. Historical control study
D. Open-label study
A. Cross-sectional study
*Observational studies include cross-sectional studies, case-control studies and cohort studies
* A cross-sectional study is conducted at a point in time over a short period usually to determine the prevalence of an event in a given population (a “snapshot” of an outcome).
* A crossover study is a type of experimental study, instead of an observational study, and is a randomized trial in which subjects are randomly allocated to a sequence of two or more treatments given consecutively; study participants are initially assigned to one condition or treatment and subsequently switched to the alternate treatment or condition at some point in study.
* A historical control study is a type of experimental controlled trial in which results from participants receiving an intervention are compared with outcomes from patients treated before the new intervention was available and is used when alternative therapy is unavailable and a placebo-controlled trial is considered unethical.
An open-label study is a type of experimental study in which both the subjects and investigators are aware of the treatment the subject is receiving.
*An open-label study is a type of experimental study in which both the subjects and investigators are aware of the treatment the subject is receiving.
Which of the following study designs can help to determine causality?
A. Case Series
B. Case Control Study
C. Cross Sectional Study
D. Randomized Clinical Control Trial
D. Randomized Clinical Control Trial
- The randomized clinical trial (RCT) is the only one of the listed studies that can prospectively control for confounders, limit bias, and allow for determination of causation.
- You can see there are two independent groups who have been prospectively followed and do not cross over.
All of the following are benefits of the randomization process for clinical trials EXCEPT:
A. Randomization ensures all participants have an equal chance to be in the intervention or control group
B. Randomization provides one of the most cost efficient types of trial designs
C. Randomization minimizes bias created by unbalanced treatment allocations
D. Randomization helps to ensure validity of statistical tests
B. Randomization provides one of the most cost efficient types of trial designs
- The main advantages of the randomization process include minimizing bias, assuring validity of statistical tests, and allowing study participants an equal opportunity to be in any of the treatment groups.
- Randomized controlled trials, however, are some of the most time-consuming. expensive trials to conduct.
High-Yield Core Concept:
* One of the main reasons for utilization of randomization in a clinical trial is to reduce the risk of bias, specifically selection bias, so that the internal validity of clinical trial.
A 52-year-old woman began experiencing severe musculoskeletal pain 13-months after initiating alendronate (Fosamax) therapy for osteoporosis requiring treatment discontinuation. You are aware of 7 additional female patients who have also reported this same reaction to alendronate. How could these data best be reported in the literature?
A. Case series
B. Cross-sectional study
C. Letter to the editor
D. Case report
A. Case series
- A case study is a descriptive study that records events, observations, or activities that occurred retrospectively in a single patient, while a case series describes these occurrences in a number of patients.
- Case studies or series are retrospective, not blinded or randomized, with no clearly defined outcomes, but may serve as springboards for future research.
- A cross-sectional study is an observational study conducted at a point in time over a short period usually to determine the prevalence of a predefined outcome or event in a given population (a “snapshot” of an outcome).
- A letter to the editor is used primarily to comment on/critique data presented in original research and may present the author’s own scientific observations in response to some point made in the original research. These letters have strict guidelines and are usually published within three to six months of the original research publication.
In a randomized, double-blind, multicenter trial, investigators evaluated the safety and efficacy of a new flu vaccine in adult patients over five flu seasons. Patients were randomized to treatment groups based on age (18-64 years of age or 65 years of age and older) and treatment region in groups of 6. What type of randomization process was used in this trial?
A. Simple random assignment
B. Simple randomization
C. Block randomization
D. Stratified block randomization
D. Stratified block randomization
- Randomization is used in clinical trials to create comparison groups as similar as possible.
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Randomization with stratification ensures that any characteristic that could potentially affect study outcomes or prognosis will be divided evenly among treatment groups. * For example, subjects can be stratified based on age, treatment center, or presence or absence of disease state.
Block randomization is used to confirm that treatment groups are balanced with respect to the number of subjects per treatment allocation. - Block sizes must be divisible by the number of treatment groups included in the study.
- For example, a block size of 4 has 6 possible ways to randomly assign subjects to treatment groups and provide equal subject numbers in each treatment: AABB, ABAB, ABBA, BABA, BBAA, BAAB.
Randomization with stratification is one of the best ways to ensure that treatment groups are as comparable as possible with respect to subject characteristics and numbers.
* Note:
* This is a difficult question/concept for anyone to wrap their minds around. In an effort to keep this as simple as possible, this question explains a study that initially stratified patients into one of two main groups (like done in most comparative trials). The researchers then went on further after stratification to place patients into one of six groups based on geographic region, which is treated as blocks. Block randomization is basically an effort to randomize patients into groups (blocks) with the same same size in each and to maintain that balance over time.
Investigators recruit 50 patients to determine if an investigational drug therapy is safe. The drug is administered in escalating oral doses of 100 mg daily, 200 mg daily, and 400 mg daily for 2 weeks and the investigators then assess the data for safety and optimal dosage. This is an example of a:
A. Phase 4 trial
B. Phase 3 trial
C. Phase 2 trial
D. Phase 1 trial
D. Phase 1 trial
- Phase 1 trials are the first step in the four-trial series that evaluate drug safety and efficacy in humans. This type of trial is implemented to determine whether a drug is safe, decides the most tolerable dosage, and identifies side effects.
- Phase 2 trials broaden the scope of investigation and include larger patient numbers (100-300) and evaluate efficacy as well as safety.
- Phase 3 trials involve even larger patient numbers (hundreds to several thousand) and further investigate efficacy by comparing the newer agent to standard therapy as well as safety.
- Phase 4 trials are post-marketing studies designed to collect additional data about the newer drug therapy and to provide additional monitoring of safety and effectiveness.
Investigators are interested in conducting a one-year trial to assess efficacy and bleeding events in patients prescribed a new anti-platelet agent recently marketed to manage acute coronary syndrome. How would this trial be classified?
A. Phase 0 trial
B. Phase 3 trial
C. Phase 4 trial
D. Cross-sectional study
C. Phase 4 trial
- Phase 4 trials are conducted after a drug product has been marketed (also called postmarketing surveillance trials) to compared the new agent to agents already available as well as evaluate long-term safety and efficacy.
- Phase o trials are preliminary pharmacokinetic/pharmacodynamic studies involving small patient numbers (approximately 10 subjects) without therapeutic or diagnostic intent designed to determine whether a drug warrants additional investigation.
- Phase 3 trials are large safety and efficacy studies conducted prior to marketing involving approximately 1000 to 3000 subjects.
- A cross-sectional study is conducted at a point in time over a short period usually to determine the prevalence of an event in a given population (a “snapshot” of an outcome).
Researchers desire to assess whether smoking cessation behavioral modification or nicotine replacement therapy impact smoking cessation rates in adult blue collar workers in a large urban area. Researchers plan to collect data over a 1-year time period. What type of trial design should be used to evaluate this issue?
A. Case-control study
B. Randomized, placebo-controlled study
C. Cohort study
D. Crossover study
C. Cohort study
- A cohort study is a type of observational study that follows a group of people over time, either prospectively or retrospectively, and determines the correlation between identified risk factors and outcomes.
- A case-control study is an observational study that identifies a group with an outcome/event (cases) and a group without the outcome/event (controls) and then looks back retrospectively for potential risk factors and determines and association between the risk factor and the outcome/event.
- A randomized, placebo-controlled study randomly assigns subjects to either the intervention or placebo and determines whether statistical differences exist with the intervention compared to placebo.
When evaluating a new study that was published, which of the following would be known to reduce the risk of bias, and thus improve the internal validity of that study? (Select all that apply)
A. Single-center
B. Prospectively carried out
C. Double-dummy interventions
D. Randomization that is centralized
Correct Answer: Prospectively carried out, Double-dummy interventions, Randomization that is centralized
In a randomized, controlled trial, investigators wanted to determine whether ibuprofen would have detrimental effects on blood pressure control in 25 elderly hypertensive patients. Patients randomly received either hydrochlorothiazide (HCTZ) plus ibuprofen or HCTZ plus placebo for 4 weeks, followed by a 2-week washout period. Patients then received the opposite therapy for 4 weeks. This is an example of a(n):
A. Active controlled trial
B. Historical control trial
C. Parallel design trial
D. Crossover trial
D. Crossover trial
- Parallel design trial structure involves subjects randomly assigned to only one treatment (i.e., either one of the treatment groups or the control group) who are there for the study duration.
- A crossover trial study designs randomly assign participants to either the treatment or control group for a particular time period and then switch them to the other study group at some point in the trial.
- An active controlled trial is a study design in which a new treatment is compared to a standard treatment (no placebo), while a historical control trial involves data that were collected prior to the beginning of a clinical trial.
In clinical trials, the technique in which the treatment status for experimental and control groups is concealed from study participants and/or investigators is best defined as:
A. Blinding
B. Stratification
C. Randomization
D. Washout period
A. Blinding
- In clinical trials, blinding is used to minimize outside influences skewing data interpretation by not allowing the investigators and/or subjects to determine who is in the intervention or control group.
- Randomization is a technique used to give every person enrolled in a clinical trial an equal opportunity to be in the experimental or control group, while stratification is a more sophisticated method of randomization in which specific characteristics are identified and used to determine to which treatment groups subjects will be assigned so that significant imbalances of these characteristics will not be present in treatment groups.
- A washout period is the period between treatments in a crossover trial in which no drug therapy is given to minimize carryover effects of the study medications.
