Transcript Hands-on session: Cox proportional hazard analysis

Advanced Statistics
for Interventional
Cardiologists
Why waisting time with
advanced statistics?
BMJ 2003
What you will learn
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Introduction
Basics of multivariable statistical modeling
Advanced linear regression methods
Hands-on session: linear regression
Bayesian methods
Logistic regression and generalized linear model
Resampling methods
Meta-analysis
Hands-on session: logistic regression and meta-analysis
Multifactor analysis of variance
Cox proportional hazards analysis
Hands-on session: Cox proportional hazard analysis
Propensity analysis
Most popular statistical packages
Conclusions and take home messages
1st day
2nd day
What you will NOT learn – as some
knowledge is necessary for this course!
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Descriptive statistics
Probability distributions
Inferential statistics
Finding differences in mean between two groups
Finding differences in mean between more than 2 groups
Linear regression and correlation for bivariate analysis
Analysis of categorical data: contingency tables
Analysis of time-to-event data: survival analysis
BUT IF YOU ARE STILL INTERESTED, ASK MEDTRONIC
TO SPONSOR YOU FOR THE UPCOMING
BIOSTATISTICS COURSE DUE IN JUNE 2009
What you will learn
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Introduction
Basics of multivariable statistical modeling
Advanced linear regression methods
Hands-on session: linear regression
Bayesian methods
Logistic regression and generalized linear model
Resampling methods
Meta-analysis
Hands-on session: logistic regression and meta-analysis
Multifactor analysis of variance
Cox proportional hazards analysis
Hands-on session: Cox proportional hazard analysis
Propensity analysis
Most popular statistical packages
Conclusions and take home messages
1st day
2nd day
Science or fiction?
There are three kind of lies: lies, damn
lies, and statistics
B. Disraeli
Knowledge is the process of piling up
facts, wisdom lies in their simplification
M. Fisher
What is statistics?
DEFINITIONS
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A whole subject or discipline
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A collection of methods
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Collections of data
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Specially calculated figures
What is statistics?
DEFINITIONS
•
A whole subject or discipline
•
A collection of methods
•
Collections of data
•
Specially calculated figures
A collection of methods
Statistics is great
Find out stuff
– Finding stuff out is fun
• Feel like you have done something
• It’s small, but it’s something
Understand stuff
– When are we being deceived
– Support, or illumination?
Ultimate goal: appraisal of causation
Methods of inquiry
Statistical inquiry may be…
Descriptive
(to summarize or describe an observation)
or
Inferential
(to use the observations to make estimates or predictions)
Descriptive statistics
100
100
AVERAGE
Samples and populations
This is a sample
Samples and populations
And this is its
universal population
Samples and populations
This is another sample
Samples and populations
And this might be its
universal population
Samples and populations
But what if THIS is its
universal population?
Samples and populations
Any inference thus
depend on our confidence
in its likelihood
Inferential statistics
If I become a scaffolder, how likely
I am to eat well every day?
P
values
Confidence
Intervals
Inferential statistics
Mauri et al, New Engl J Med 2007
Inferential statistics
Mauri et al, New Engl J Med 2007
Focus on p values
Mauri et al, New Engl J Med 2007
Focus on confidence intervals
Mauri et al, New Engl J Med 2007
Types of variables
Variables
CATEGORY
nominal
QUANTITY
ordinal
discrete
continuous
ranks
counting
measuring
TIMI
flow
Stent diameter
Stent length
BMI
Blood pressure
QCA data (MLD, late loss)
Death: yes/no
TLR: yes/no
ordered
categories
Paired vs unpaired data
Variables
PAIRED
OR
REPEATED
MEASURES
eg
• blood pressure measured
twice in the same patients
at different times
• MLD measured at
different times in the
same segment
UNPAIRED
OR
INDEPENDENT
MEASURES
eg
• blood pressure measured
in several different groups
of patients only once
• MLD measured at the
same time in different
vessels
For further slides on these topics
please feel free to visit the
metcardio.org website:
http://www.metcardio.org/slides.html