epi tools everyone can use emily mosites, mph alice green, dvm katie garman, mph
TRANSCRIPT
Epi Tools Everyone Can Use
Emily Mosites, MPH
Alice Green, DVM
Katie Garman, MPH
Objectives
• Review concepts from regional outbreak training– Line list– Resources for outbreaks
• Demonstrate use of statistical software to develop– Epi-curve– Symptom profile– 2x2 tables (OR, RR)
• Data management/ analysis tips
Regional Outbreak Training Objectives
• Provide Regional Health Departments with tools to investigate clusters and outbreaks
• Today: foodborne diseases– Concepts are generalizable
• Promote collaboration and understanding between epidemiologists/CEDS staff, environmentalists, and laboratorians– “Epi-Ready” model
The “Stool”
Foodborne illness Foodborne illness investigationsinvestigations
Lab
Lab
Epi
dem
iolo
gy
Epi
dem
iolo
gy
Env
iron
men
tal
Env
iron
men
tal
Foodborne illness Foodborne illness investigationsinvestigations
Lab
Lab
Epi
dem
iolo
gy
Epi
dem
iolo
gy
Env
iron
men
tal
Env
iron
men
tal
Epi Tools
Tools
• Many tools you can use
• Today’s focus– Excel– SAS– EpiInfo
Compile a Line list: Excel
Data Entry Tips
• Blank does not equal “No”
• Single-word variable name
• Use 1= yes & 0= no OR 1=yes & 3=no– Proper alignment to calculate RR
Analysis in Excel
Why Excel?
If you don’t want to start having dreams in SAS code
If you have never heard of EpiInfo
If you find yourself doing analysis in the middle of the woods with only Microsoft ® Office™
USE EXCEL!!!
Overview
• Summarizing Data with PivotTables
• RR, OR, and Chi Squares Test Page
• Incubation period and EpiCurve
We will send you an excel workbook with these formulas and explanations!
Why use SAS in an outbreak investigation?
• It’s powerful•Fisher’s exact•Easy to screen large numbers of variables
• It’s subsidized by CDC• It’s fun!!
• Embrace your dorkiness
Fisher’s Exact Test
Meal Date (exposure)
Illness Onset Date
End Illness Date
• Why use Epi-Info (Version 3.5.1)– Easy
• Point and click• Rapid questionnaire development• Simple commands
– Accessible• available anywhere at anytime at www.cdc.gov
– FREE
www.cdc.gov/epiinfo
Click on analyze data
Click on Read (Import)
Select the correct data
format
Find your file
Make sure all of your records have
been imported
Start looking at your data
Select Select your variable
Type “=1” to select those who were sick
ListSelect your variable
Sick = 1 is selected
To unselect click on cancel select
Create symptom profile using frequency command
Frequencies
Select your
variables
Stratify by sick
Symptom Profile
Develop an epi curve using the graph command
GraphSelect Bar
Choose onset date
Calculating relative risk or odds ratio using the tables
command
Remember…• In order to calculate
RR– 1= yes– 3= no
0
well
1
ill
BBQ 15 20
No BBQ
20 5
RR= 15/(15+20) = 0.53
20/(20+5)
1
ill
3
well
BBQ 20 15
No BBQ
5 20
RR= 20/(20+15) = 2.85
5/(5+20)
Add outcome variableAdd exposure variable
BBQ Chicken
Sweet Tea
Resources for Outbreaks
http://health.state.tn.us/ceds/resources.htm
Sample databases
Modifiable gastrointestinal outbreak questionnaires
Thank you!
• Connie Robinson and staff
• Rand Carpenter
• John Dunn
Questions
• Emily: [email protected]
• Alice: [email protected]
• Katie: [email protected]
615-741-7247