FOM 1.4.1 Flashcards
What does EBM stand for?
Evidence-Based Medicine
Name the three areas that EBM tries to combine.
1) Individual Clinical Expertise 2) Best External Evidence 3) Patient Values & Expectations
Define evidence-based medicine.
A systematic approach to clinical problem solving that allows the integration of the best available research evidence w/ clinical expertise & patient values.
EBM helps us address what 3 issues
1) ever-expanding literature base 2) complexity of modern medicine 3) limited amount of time
What are the 6 steps of the EBM process?
1) ask a clinical ? 2) search the literature 3) critically evaluate the info 4) Weigh literature against other info 5) Apply to clinical case 6) Assess effectiveness
What is epidemiology?
Study of distribution & determinants of dz
Define clinical epidemiology.
Application of population-based info to decision making about individual patients
What are two quantifying measures of occurrence?
1) Incidence 2) Prevalence
What is morbidity?
- A dz’ed condition or state 2. The incidence or prevalence of a dz or of all dz’s in a population
Define Incidence.
NEW cases of dz that develop in a susceptible population over a given period of time.
Define prevalence.
EXISTING cases of a dz (new & old) in a susceptible population.
Name the type of prevalence that looks at amount of dz at one point in time.
Point prevalence. Most commonly used type of prevalence
Name the type of prevalence that looks at amount of dz present in a population during a defined period of time.
Period prevalence
Define cumulative incidence (risk).
Probability that individual will contract a dz.
Define incidence rate.
How fast new occurrences of dz arise.
Prevalence = __ /___
of existing individuals with dz / # of persons in population
Cumulative Incidence, CI (risk of acquiring) = __ / __
New cases / persons at risk
Incidence Rate (IR) = __ / __
of new cases / total person time
Incidence rate: is it a proportion? What is its range?
Not a proportion Range: 0 to infinity
What are the units of incidence rate?
cases per person-year
In epidemiology, what is the most commonly used type of rate?
Avg rates
If you follow 60 people for 6 months and have 90 new cases, what is the incidence rate?
3 cases per person-year
If you increase the incidence of a dz, how would the affect prevalence?
Increase prevalence
If a new treatment provides a longer life span for those who are dz’ed, how is the prevalence affected?
Increased prevalence (e.g. AIDS)
Which occurrence variable do vaccinations directly affect? And, how?
Incidence, decrease
What happens to prevalence if: number of people dying from the dz increases?
Prevalence decreases.
An oatmeal manufacturer has an ad campaign claiming that a diet high in grains helps prevent colon cancer. To evaluate this claim, is it necessary to measure incidence or prevalence?
Incidence.
What does 5-year survival measure?
% of patients alive 5 yrs after treatment begins or 5 yrs after diagnosis (measure to prognosis)
Define median survival time.
Time following diagnosis at which half of patients remain event-free.
How does a Kaplan-Meier Method plot look?
Like an uneven staircase. Each individual event and tracked (mostly likely different time periods b/t events)
Why are hazard rates calculated over shorter periods of time then aggregated?
If time period is long, rate may change over time.
Cumulative mortality = __
Cumulative incidence
Mortality rate = __
Incidence rate
Mortality rate = __ / __
of deaths / total person-time observed
What is the difference between a crude and adjusted rate?
Crude rates are expressions of raw data. In an adjusted rate, the rates can be standardized to allow for comparison b/t groups. (i.e. Adjusting mortality rates to factor in age)
Case Fatality = __ / __
of ppl dying from dz / # of ppl who contracted dz
Is case fatality a proportion?
Yes, it’s range is always between 0 and 1.
What is years of potential life lost?
Measure of premature morality (compares age of death to avg lifespan)
What is years of potential life lost?
Measure of premature morality (compares age of death to avg lifespan)
What is different b/t quality -adjusted life years (QALYs) and years of potential life lost?
QALYs applies weight ranges from 0 to 1 (0 = dead) that corresponds to quality
What is used to assess value for money of a medical intervention?
QALYs
What is the complement of QALYs?
Disability-adjusted life years (DALYs)
What does disability-adjusted life years measure?
Healthy years lost
How are DALYs and QALYs similar?
Both take life expectancy into account.
Give an example of nominal calculations.
% and proportion
Give an example of Ordinal measures.
Tumor staging, Likert scales Similar to a race, there is an order but the difference b/t two values may not be the same like distance b/t 1st and 2nd may be different than distance b/t 2nd and 3rd
An example of numerical measures.
Interval, rate (i.e. Age)
What does a large standard of deviation mean? How it affect a graph?
It means the values are more spread out. The curve will be flattened over a longer area.
What is the importance of having a p-value of 0.05?
The data is within two standard deviations
When the correlation coefficient (r) of a set of values is 1, how do the individual values fit the line of best fit?
They are right on top of it. High correlation.
What’s the relationship strength of these (r) values? 0.0 - 0.25: __ 0.25 - 0.5: __ 0.5 - 0.75: __ 0.75 - 1: __
0.0 - 0.25: Little 0.25 - 0.5: Fair 0.5 - 0.75: Moderate/good 0.75 - 1: Very good/excellent
What does a r value (correlation coefficient) of -1 represent?
A perfect negative correlation.
Answer
No because the prevalence line is rising meaning patients w/ said disease are living longer
Yes, annual incidence are decreasing
Yes, prevalence is rising
No, prevalence is rising
