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Flashcards in Important of evidence in medicine Deck (15):

Which of the following is NOT important to consider when assessing whether a relationship is causal?
o Experimental evidence
o Consistency
o Plausibility
o Disease Prevalence
o Specificity

Disease prevalence


Which criteria is essential for a casual pathway between an exposure and an outcome?
o Consistency with other investigations
o Temporal relationship
o Experimental evidence
o A strong association
o Plausibility

Temporal relationship


What is the best way of addressing bias?
o Through statistical analysis e.g. regression
o By increasing the power of the study
o Considering potential bias in your study
o Through Standardisation
o By repeating the study

Considering potential bias in your study


What is the role of evidence based practice in clinical medicine?

Clinical findings- how to properly gather + interpret findings from history and physical examination

Aetiology- identifying causes of disease

Clinical manifestations of disease- knowing how often and when disease causes clinical manifestations

Differential diagnosis

Diagnostic tests
- how to select and interpret diagnostic tests, to confirm or exclude a diagnosis

-how to estimate a patient's likely clinical course over time and anticipate likely complications

- how to select treatments to offer a patient that do more good than harm and that are worth the efforts and costs of using them.

- how to reduce the chance of disease by identifying and modifying risk factors and how to diagnose disease early by screening.


List and the hierarchy of evidence in study design

Systematic review and meta-analyses, RCT, cohort studies, case-control studies, ecological studies, descriptive/ cross-sectional studies, case report/ series


Describe advantages systematic review and meta analyses

Way of getting round problems of expense and needing large sample size in RCTs, can use smaller studies and pool results


Describe an RCT

Gold standard for clinical trials + surgical interventions, they are expensive and need large sample size to demonstrate an effect. The people participating in the trial are randomly allocated to either the group receiving the treatment under investigation or to a group receiving standard treatment (or placebo treatment) as the control. Randomization minimises selection bias and the different comparison groups


Describe cohort studies

You have a group of people before they develop condition then look at exposures and risk factors. They are followed over time to see who gets disease of interest. Better for common conditions and less prone to bias


Describe case-control studies

Two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Useful for rare conditions.


Describe ecological studies

Type of descriptive study which uses correlations between different populations using different exposures. EG Alcohol consumption by country per capita vs liver cirrhosis rate


Describe descriptive/ cross-sectional studies

Based on routinely collected data, difficult to show a causal relationship. A cross-sectional study is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time


Descriptive case report

Description of single/ series of cases. This is NOT evidence used to support practice but can be useful in picking out new syndromes or conditions


Why does EBM matter to clinicians?

patient care, patient safety, medical knowledge, professionalism, revalidation


How are epidemiological skills applied to clinical decision making

Much of what underpin clinical medicine is epidemiological evidence (the study of the distribution of health-related states/events and the determinants of health-related states in specified populations, and the application of this study to control health problems- to promote, protect and restore health)


Why were studies suggesting MMR caused autism flawed?

They didn't explain 3 factors- bias, chance and confounding factors