8. Use of pertinent treatment guidelines 3 Flashcards
What is a cohort study?
A cohort study is an observational study design that involves monitoring a large number of individuals over a long period of time commonly years to compare incidence rates of diseases or outcomes in groups that differ based on their exposure levels. It allows researchers to observe the natural progression of diseases and the effects of risk factors.
What does ‘concealment of allocation’ mean in the context of a clinical study?
‘Concealment of allocation’ refers to the precautions and methods employed to ensure that the groups to which participants are assigned in a study remain undisclosed prior to their actual allocation. This process helps minimize bias in the assignment of participants to ensure the integrity of the study process.
Define ‘confounding variable’ and explain its significance in research.
A confounding variable is an extrinsic factor that is correlated with both the exposure being studied and the outcome of interest. Its presence can distort the apparent relationship between the exposure and outcome making it difficult to ascertain causation. Recognizing and controlling for confounding variables is crucial to obtaining valid research results.
What is a cross-sectional study and what does it measure?
A cross-sectional study is a type of observational research that looks at the relationship between diseases or health-related characteristics and other variables of interest within a defined population at a specific point in time. It primarily measures disease prevalence rather than incidence and it cannot adequately establish temporal relationships between causes and effects.
What is the difference between disease prevalence and disease incidence as recorded in studies?
Disease prevalence refers to the total number of existing cases of a disease in a population at a specific time while disease incidence measures the number of new cases that develop in a population over a defined time period. Cross-sectional studies typically focus on prevalence.
What is a diagnostic test?
A diagnostic test is any medical procedure or examination used to determine the presence or absence of a disease condition or health issue in a patient. These tests may include laboratory tests imaging studies and physical exams.
What is the purpose of diagnostic tests?
Diagnostic tests are performed to confirm or determine the presence of disease in an individual suspected of having the disease. Typically this is done following the report of symptoms or based on the results of other medical tests.
Give two examples of diagnostic tests.
- A chest x-ray to diagnose pneumonia. 2. A skin biopsy to detect cancerous cells.
Define ‘disease incidence’.
‘Disease incidence’ refers to the measure of new cases of a disease or condition occurring in a specified population over a particular period of time.
Define ‘disease prevalence’.
‘Disease prevalence’ refers to the total number or rate of cases of a disease or condition present in a population at a specific point in time.
What does ‘expert opinion’ mean in a medical context?
‘Expert opinion’ refers to a determination made by experts through an evidence-based process recommending whether a particular medical practice should or should not be performed. This opinion is typically published in a peer-reviewed medical journal.
What is an inception cohort study?
An inception cohort study is a type of research design where a group of individuals is identified for subsequent study at an early uniform point in the course of a specified health condition or even before the condition develops.
What is defined as the ‘index test’?
The ‘index test’ is the diagnostic procedure or test being evaluated in a study to determine its accuracy or effectiveness in diagnosing a particular disease or condition.
What does ‘Intention to treat’ mean in the context of randomized controlled trials?
‘Intention to treat’ is a principle in the conduct and analysis of randomized controlled trials where all patients allocated to a given arm of the treatment regimen are included in the analysis regardless of whether they received or completed the prescribed regimen. This approach is critical for preserving the benefits of randomization and ensuring the validity of the study results.
What are the consequences of not adhering to ‘Intention to treat’ analysis in clinical trials?
Failure to follow ‘Intention to treat’ analysis can defeat the main purpose of random allocation leading to biased results and potentially invalid conclusions about the effectiveness of the treatment under study.
What does ‘Low risk of bias’ refer to in clinical trials?
‘Low risk of bias’ refers to trials or studies that have methodological safeguards in place to protect against various biases including those arising from financial interests academic interests industry influence and other issues related to the randomization sequence allocation concealment selection bias blinding selective outcome reporting early stopping and adherence to the intention to treat principle.
What are some factors that can contribute to bias in clinical trials?
Factors that can contribute to bias in clinical trials include: vested financial interests academic biases influence from the industry improper generation of randomization sequence lack of allocation concealment selection bias improper blinding selective reporting of outcomes and premature stopping of trials.
Define ‘Meta-analysis’.
Meta-analysis is a mathematical process that combines results from two or more studies using a method that provides weights to each study based on their statistical significance and reliability allowing for a more comprehensive understanding of the overall efficacy of a treatment or intervention.
What is the importance of the statistical weighting in a meta-analysis?
Statistical weighting in a meta-analysis is important because it accounts for the varying sizes and precisions of individual studies ensuring that larger more reliable studies have more influence on the overall results than smaller less reliable studies.
What is a ‘randomized controlled trial’ (RCT)?
A randomized controlled trial (RCT) is a study design that randomly assigns participants to either a treatment group or a control group allowing researchers to evaluate the effect of an intervention while minimizing biases and confounding variables.
Why is randomization important in clinical trials?
Randomization is important in clinical trials because it helps to eliminate selection bias ensuring that treatment groups are comparable and that the results can be attributed to the intervention rather than to differences between the groups.
What is allocation concealment and why is it important?
Allocation concealment is the practice of keeping the allocation sequence hidden from participants and researchers until the moment of assignment. It is important to prevent selection bias ensuring that neither participants nor researchers can influence which treatment group participants are assigned to.
What is the role of blinding in clinical trials?
Blinding in clinical trials refers to the practice of keeping participants caregivers and/or researchers unaware of which participants are receiving the treatment or control which helps to minimize bias in treatment administration reporting and outcome assessment.
What is likelihood variance?
Likelihood variance refers to the extent to which the observed results of a study are expected to vary from the true value or parameter being estimated. A lower likelihood variance indicates that the results are more likely to be closer to the truth.
What does ‘post-marketing surveillance’ mean?
Post-marketing surveillance is a procedure implemented after a drug has been licensed for public use. It is designed to gather information on the actual use of the drug for specific indications and to monitor the occurrence of side effects adverse reactions etc. This method is particularly useful for identifying adverse drug reactions especially those that are rare.
What is the definition of prognosis in medical terms?
Prognosis refers to the anticipated prospect of survival and recovery from a disease based on the usual course that the disease takes or indicated by special features of a particular case.
What is a randomized trial?
A randomized trial is a type of clinical experiment where subjects within a population are randomly allocated into groups typically called study and control groups. These groups receive either the experimental diagnostic preventive or therapeutic intervention or no intervention at all. The results are then assessed by comparing rates of disease death recovery or other relevant outcomes.
Why is post-marketing surveillance important?
Post-marketing surveillance is critical for ensuring drug safety as it helps in identifying long-term effects side effects and rare adverse drug reactions that may not have been evident in pre-marketing clinical trials.
How does randomization in trials help eliminate bias?
Randomization helps eliminate bias by ensuring that each participant has an equal chance of being assigned to any treatment or control group. This minimizes the potential for selection bias and ensures that the groups are comparable thus enhancing the validity of the study’s results.
What types of outcomes can be assessed in a randomized trial?
In a randomized trial outcomes can include rates of disease incidence mortality (death) recovery rates and other significant clinical events or measures relevant to the study’s hypotheses.
What are the components that influence prognosis?
Prognosis can be influenced by variables such as the type and stage of the disease the patient’s overall health age comorbid conditions and specific features of the case (such as genetic markers or response to previous treatments).
What is the significance of identifying rare adverse drug reactions?
Identifying rare adverse drug reactions is significant because these reactions may not be detectable in smaller clinical trials but can have serious consequences for public health. Understanding these reactions helps healthcare providers make safer prescribing decisions.
What is the relationship between prognosis and treatment options?
Prognosis informs treatment options by providing insights into the expected outcome of a disease which can guide healthcare professionals in selecting appropriate interventions and setting realistic treatment goals tailored to individual patients.
What is the meaning of ‘Reference standard’ in clinical studies?
‘Reference standard’ refers to the gold standard to which an index test (the test being evaluated) is being compared.
What does ‘Risk of bias’ mean in clinical trials?
‘Risk of bias’ refers to the potential introduction of bias into trials due to methodological insufficiencies. These biases can relate to vested interests (financial academic industry influence) or issues related to randomization sequence generation allocation concealment selection blinding selective outcome reporting early stopping and intention to treat.
Define ‘Selective outcome reporting’ in the context of clinical research.
‘Selective outcome reporting’ is the practice of failing to report all of the outcomes that are measured in a trial including any post hoc changes to the primary outcome.
What is a ‘Systematic review’ and its purpose?
A ‘Systematic review’ is an approach that applies strategies to minimize bias in the gathering critical appraisal and synthesis of all relevant studies on a specific topic. Its purpose is to focus on peer-reviewed publications that address a specific research question.
List some methods that can introduce ‘Risk of bias’ in clinical trials.
Methods that can introduce ‘Risk of bias’ include:
- Poor generation of randomization sequence
- Inadequate concealment of allocation
- Improper selection and recruitment of participants
- Lack of blinding for participants and personnel
- Selective outcome reporting
- Early stopping of trials without proper justification
- Not adhering to intention to treat analysis.
What are the consequences of ‘Selective outcome reporting’ in clinical trials?
Consequences of ‘Selective outcome reporting’ can lead to misleading conclusions about the effectiveness or safety of an intervention as it may bias the interpretation of results by only presenting positive or favorable outcomes while ignoring negative or neutral results.
How does a ‘Systematic review’ differ from a narrative review?
A ‘Systematic review’ is structured and methodical focusing on minimizing bias and analyzing all relevant studies comprehensively using predefined criteria. A narrative review on the other hand can be more subjective summarizing studies without a rigorous methodological approach or comprehensive sourcing.
What are the key components of a ‘Systematic review’?
Key components of a ‘Systematic review’ include:
- Clear research question
- Comprehensive literature search strategy
- Inclusion and exclusion criteria for selecting studies
- Critical assessment of the quality of included studies
- Data extraction and synthesis of findings
- Discussion of implications and future research directions.
Why is blinding important in clinical trials?
Blinding is important in clinical trials because it helps to avoid bias in treatment administration and outcome assessment ensuring that neither participants nor researchers can influence results based on knowledge of the treatment being given.
What is a systematic review?
A systematic review is a comprehensive and rigorous method for assessing and synthesizing research articles on a particular health problem. It involves a structured approach to selecting relevant studies and evaluating their quality to draw conclusions based on the available evidence.
How does a systematic review differ from a meta-analysis?
A systematic review differs from a meta-analysis in that it does not include a quantitative summary of results. While a systematic review summarizes existing literature a meta-analysis statistically combines the results of multiple studies. However a meta-analysis may be included as a part of a systematic review.
What does ‘treatment benefits’ refer to?
‘Treatment benefits’ refer to positive patient-relevant outcomes that result from an intervention. These benefits can be measured using epidemiological measures such as absolute risk reduction and the number needed to treat.
What is meant by ‘treatment harms’?
‘Treatment harms’ refer to adverse patient-relevant outcomes associated with an intervention. These harms can be identified using epidemiological measures such as absolute increased risk of occurrence and the number needed to harm. Treatment harms can also be tracked through post-marketing surveillance.
What are epidemiological measures?
Epidemiological measures are statistical tools used to quantify health outcomes in populations allowing for the estimation of risks benefits and harms associated with medical interventions. Common measures include absolute risk reduction number needed to treat and absolute increased risk.
What is absolute risk reduction (ARR)?
Absolute risk reduction (ARR) is a measure that quantifies the decrease in risk of an adverse event occurring in a treatment group compared to a control group. It is calculated by subtracting the risk in the treatment group from the risk in the control group.
What does ‘number needed to treat’ (NNT) mean?
‘Number needed to treat’ (NNT) is an epidemiological measure that indicates the number of patients who need to be treated with a specific intervention in order to prevent one additional adverse outcome. A lower NNT indicates a more effective treatment.
What is the ‘number needed to harm’ (NNH)?
The ‘number needed to harm’ (NNH) is an epidemiological measure that indicates the number of patients who need to be treated with a specific intervention to cause one additional adverse outcome. A higher NNH indicates a lower risk of harm.
What role does post-marketing surveillance play in assessing treatment harms?
Post-marketing surveillance plays a critical role in identifying treatment harms after a medical intervention has been released to the market. It involves the ongoing monitoring of a drug’s effects in the general population to detect any adverse events that were not identified in clinical trials.
