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

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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: Emily.Mosites@tn.gov

• Alice: Alice.Green@tn.gov

• Katie: Katie.Garman@tn.gov

615-741-7247