Workshop 11 - clinical trial design Flashcards
what are case reports?
An article that describes and interprets an individual case, often written in the form of a detailed story. Case reports often describe:
* Unique cases that cannot be explained by known diseases or syndromes
* Cases that show an important variation of a disease or condition
* Cases that show unexpected events that may yield new or useful information
* Cases in which one patient has two or more unexpected diseases or disorders
considered lowest level of evidence, also first lien of evidence because they are where ewe ideas emerge.
what are advantages and disadvantages of case control studies ?
advantages:
Quicker and more cost-effective to publish than larger research studies.
Important for documenting unexpected adverse reactions or the effects of new treatments.
help identify new diseases or adverse effects of treatments, generating hypotheses for further study
erve as a valuable educational tool for clinicians and healthcare students.
Provide detailed insight into rare, novel, or unique conditions that may not be captured in larger studie
disadvantages:
Single observations cannot be generalized to the larger population.
Without a control group, it is impossible to determine causality
Considered low-level evidence because they are anecdotal and subject to bias.
Cannot provide statistical power due to the involvement of typically one or a few patients
What are the design pitfalls to look out for with case reports?
Selection Bias, Confirmation Bias: Authors may select cases that support their own hypotheses or clinical beliefs.
Inadequate Peer Review may lack credibility and reliability.
Incomplete Information causing misinterpretation of the case.
Inadequate Consent and Anonymity: Not obtaining proper patient consent or failing to ensure the anonymity of the patients can lead to ethical concerns.
Poor Quality of Presentation: Unclear writing, lack of critical thinking, or failure to contextualize findings within existing literature can undermine the case report’s value
what is a case control study
a case control study is when a group of individual who have the disease and group who don’t are compared. They compare the frequency of the risk factors and the exposure to determine the relationship between risk factor and disease
case control studies re observation but no intervention is attempted to alter the disease course. Retrospectively examined from afar of the risk factors exposure on the disease from the two groups and estimate the odds.
what are advantage and disadvantages of case control studies ?
advantages
They are less expensive than cohort or randomized controlled trials
can be conducted relatively quickly, especially when compared to cohort studies or RCTs.
Suitable for studying rare diseases or diseases with long latency periods
Can be conducted with a much smaller sample size than other study designs.
They allow for the examination of multiple risk factors for a single disease outcome.
disadvantages:
Cannot provide data on the incidence of a disease.
Reliance on participant memory for past exposure can lead to recall bias.
selection Bias: It can be challenging to select appropriate control groups, leading to selection bias.
Generally, they are limited to assessing one outcome
There may be confounding variables that are not identified or controlled for, affecting the validity of the findings
What are the design pitfalls to look out for with case control studies?
Not choosing controls that are representative of the population from which the cases were drawn can introduce bias
ecall Bias: Cases may remember their exposures more clearly than controls, particularly if exposures are related to significant event
Improper matching can introduce bias or obscure real associations between the exposure and the outcome.
Misinterpretation of data or failure to properly analyze the relationship between exposure and outcome can lead to over- or underestimation of risk.
Difficulty establishing the timeline of exposure and onset of disease, which can make it challenging to infer causality.
what os the definition for a cohort study?
A study design where one or more samples (called cohorts) are followed prospectively and subsequent status evaluations with respect to a disease or outcome are conducted to determine which initial participants’ exposure characteristics (risk factors) are associated with it. As the study is conducted, outcome from participants in each cohort is measured and relationships with specific characteristics determined.
what are advantages and disadvantages of cohort study?
advantages:
Directly observing participants over time allows for a more accurate measurement of exposures and outcomes
They can investigate multiple outcomes for a single exposure, offering a broader understanding of the exposure’s potential effects
They provide data on the incidence of disease and thus can calculate relative risks directly.
Compared to case-control studies, they are less prone to recall and selection biases.
disadvantages
They require long follow-up periods, especially for diseases with long latency, which can delay results
They are usually more costly than case-control studies due to the scale and duration of the study
Over time, some participants may drop out, move away, or be lost to follow-up, which can bias the results
Large numbers of participants are needed, which makes them less efficient for studying rare diseases
As time passes, the classification of exposure may change, leading to misclassification bias
[What are the design pitfalls to look out for with cohort studies?]
Over time, the nature or intensity of exposures may change, affecting the study’s relevance.
Large volumes of data require robust management and analysis strategies to prevent errors.
Inconsistent criteria or methods for assessing the outcome can lead to misclassification.
articipants may drop out over time, which can bias the results if the dropouts are related to the exposure or outcome.
what is the definition for randomised clinical trials?
A study design that randomly assigns participants into an experimental group or a control group. As the study is conducted, the only expected difference between the control and experimental groups in a randomized controlled trial (RCT) is the outcome variable being studied.
what are the advantages and disadvantage of randomised controlled trials?
advantages
Randomization helps to balance known and unknown confounding variables across the treatment groups.
The design allows for strong causal inferences to be made about the effect of an intervention.
Protocols for treatment administration, monitoring, and assessment of outcomes are standardized.
RCTs often have strict ethical oversight, which can enhance the protection of participants.
RCTs are considered the gold standard in the hierarchy of evidence for evaluating the efficacy of interventions.
disadvantages
RCTs require significant resources and time to conduct.
Strict inclusion and exclusion criteria can limit the generalizability of the results to a broader population.
Participants may not adhere to the treatment regimen, which can impact the validity of the findings.
Withholding a potentially beneficial treatment from the control group raises ethical concerns, particularly if an existing standard treatment is available.
They are complex to design and execute properly, requiring expertise in multiple fields.
RCTs typically focus on a single intervention and a limited set of outcomes, which might not capture the full complexity of medical care.
what is the definition of practice guidelines studies
A statement produced by a panel of experts that outlines current best practice to inform health care professionals and patients in making clinical decisions. The statement is produced after an extensive review of the literature and is typically created by professional associations, government agencies, and/or public or private organizations.
Good guidelines clearly define the topic; appraise and summarize the best evidence regarding prevention, diagnosis, prognosis, therapy, harm, and cost-effectiveness; and identify the decision points where this information should be integrated with clinical experience and patient wishes to determine practice. Practice guidelines should be reviewed frequently and updated as necessary for continued accuracy and relevancy.
what are the advantages and disadvantages of practice guidlines or clinical guidelines?
advantages:
They provide standardized recommendations, which can reduce variability in clinical practice and improve the quality of patient care.
Guidelines are typically based on a synthesis of the current best evidence, which can assist practitioners in decision-making.
They serve as an educational resource for healthcare professionals, particularly those in training or those facing unfamiliar clinical scenarios.
By promoting best practices, guidelines can contribute to more efficient use of healthcare resources and potentially reduce costs.
Guidelines can enhance patient safety by recommending practices that have been shown to reduce the risk of errors or complications.
disadvantages
They may not account for individual patient preferences or unique clinical circumstances, which can limit clinician autonomy and patient-centered care.
Because medical research is continuously evolving, guidelines can become outdated if they are not regularly reviewed and updated.
Development of guidelines can be influenced by individuals or groups with commercial interests, potentially biasing recommendations.
There can be barriers to the adoption and implementation of guidelines in clinical practice due to a variety of factors, including resistance to change.
Clinical situations are often complex, and guidelines may oversimplify these situations, leading to suboptimal decisions if followed without consideration of the full clinical context.
[What are the design pitfalls to look out for with a practice guideline?]
nadequate Evidence Base: Guidelines should be grounded in robust, high-quality evidence. Basing recommendations on limited or poor-quality evidence can lead to ineffective or even harmful practices.
Lack of Multidisciplinary Input: Input from a single specialty or a non-diverse panel can result in guidelines that don’t fully consider all clinical aspects or patient needs.
Failure to Update Regularly: Medical knowledge evolves rapidly, and guidelines that are not updated regularly may become outdated and potentially dangerous.
Not Addressing Variability in Practice: Guidelines that do not consider different clinical settings or healthcare systems may be less applicable in certain contexts.
Conflicts of Interest: Developers of guidelines may have financial or professional interests that could unduly influence the recommendations.
Poor Methodology: Not using a systematic, transparent method for literature review and evidence synthesis can undermine the validity of the guidelines.
Overlooking Patient Preferences: Failing to incorporate patient values and preferences can limit the patient-centeredness and applicability of guidelines.
Complexity and Accessibility: Guidelines that are too complex or not easily accessible may not be used effectively by healthcare providers.
Inadequate Peer Review: Insufficient review by external experts can lead to a lack of critical appraisal and acceptance of the guidelines.
Neglecting Implementation Strategies: Without strategies and resources for implementation, even well-designed guidelines may have little impact on actual practice.
what is the definition for a systematic review
A document often written by a panel that provides a comprehensive review of all relevant studies on a particular clinical or health-related topic/question. The systematic review is 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.
