Using EpiData & Epi-Info for Windows Training for Communicable Disease Control in Local Authorities Cardiff Council (Strategic Planning & Environment) March 2007 Acknowledgements Acknowledgements © 2007 Cardiff Council (Strategic Planning & Environment). This training guide was produced by Alastair Tomlinson to form part of the Communicable Disease Lead Officer Training Programme, co-ordinated by the Wales Centre for Health. Please send enquiries relating to this training guide to: Alastair Tomlinson, Chartered Environmental Health Practitioner Team Leader (Health Improvement) Public Protection Division Room 134 City Hall Cathays Park Cardiff. CF10 3ND. 029 2087 1845 [email protected] About the software Epi Info™ is a public domain software package designed for the global community of public health practitioners and researchers. It provides for easy form and database construction, data entry, and analysis with epidemiologic statistics, maps, and graphs. Epi Info can be downloaded from http://www.cdc.gov/epiinfo EpiData Software has developed from securing the principles of Epi Info V6 for DOS to an independent documentation oriented system. EpiData can be downloaded from http://www.epidata.dk Conventions used in this training guide Text to be entered on screen is shown in this font. Directions to drop-down menu items are shown in bold type, e.g. File > SaveSave. i Table of Contents Table of Contents Acknowledgements...............................................................................i Table of Contents ..................................................................................ii Aim and Objectives ..............................................................................1 Outbreak Scenario................................................................................2 Creating a Questionnaire using EpiData .............................................3 Entering Data using EpiData ...............................................................17 Outbreak Investigation using Epi Info Analysis .................................19 Using Analysis with routine COSURV data.........................................35 Other capabilities of EpiData and Epi Info ........................................39 Appendix I – Comparison of Epi Info & EpiData ...............................44 Appendix II – Contents of course CD-ROM.......................................48 Appendix III – Further information & resources.................................49 Appendix IV – Worksheet for 2x2 table results .................................52 Appendix V – Check code example ................................................53 ii Aim and Objectives Aim and Objectives Aim of the training To provide training on the practical use of Epi Info and EpiData in communicable disease control, with particular reference to: ♦ An outbreak situation ♦ Analysis of routine Cosurv surveillance data Objectives By the end of the training delegates will: ♦ Have an understanding of EpiData and Epi-Info for Windows and their component elements ♦ Be able to use EpiData to design a data entry form for a questionnaire in an outbreak situation ♦ Be able to use EpiData to enter outbreak investigation data into a record suitable for analysis in Epi Info for Windows ♦ Be able to use Analysis to obtain useful statistical and epidemiological information from an EpiData / Epi-Info for Windows database for outbreak investigation purposes ♦ Be able to use Analysis to import routine Cosurv surveillance data into Epi-Info for Windows , and obtain useful statistical and epidemiological information 1 Outbreak Scenario Outbreak Scenario On the 17 th August, you receive a telephone call from a gentleman who reports that he and several others who attended a buffet following a funeral were suffering symptoms of food poisoning. The buffet, provided by an external caterer, was held at a local club following the funeral, and mourners arrived at the club at around 3.00 pm on 14 th August. Food left over from the buffet was placed in the main bar areas of the club for club members to consume later that day. Initial activity involves obtaining of a list of people who attended the funeral and others who may have eaten the food provided for the funeral buffet. A list of food served at the buffet has been obtained from the caterer, and cross-referenced with initial information gathered from cases. Indications are that around 70-80 people attended the funeral, and approximately 40-50 of these people may have experienced symptoms consistent with food poisoning. Table 111 --- List of foods served at the buffet sausage rolls chicken rolls salmon sandwiches pickled onions ham sandwiches egg rolls corned beef sandwiches ham rolls egg sandwiches chicken nuggets chicken sandwiches cheese & biscuits crisps gateaux pasties An Outbreak Control Team has been convened, and has decided to undertake a cohort study to investigate the outbreak. The OCT assigns you with the following tasks: ♦ Establish the case definition ♦ Develop a structured questionnaire to investigate the outbreak. ♦ Enter questionnaire data into an appropriate computer database ♦ Analyse the data to describe outbreak and identify exposures associated with illness This training uses this scenario to introduce the various functions of EpiData and Epi Info for Windows, and their particular use in outbreak investigation. 2 Creating a Questionnaire using EpiData Creating a Questionnaire using EpiData Basic Questionnaire Creation A screenshot of the main EpiData screen is shown. We want to create a new questionnaire, so select DefineDefine Data > New .QES File (It is also possible to edit an existing questionnaire, by using Define Data > Open .QES FileFileFile).File This creates an empty text file into which we can enter information. On creation of the file, the following toolbar option also becomes available. Clicking this button brings up the ‘Field pick list’ dialog. This dialog makes it easy to create different kinds of fields. As an example, we will create one or two of the basic field types in our questionnaire. 3 Creating a Questionnaire using EpiData First, type an appropriate heading into the first line of your questionnaire, such as “Lead Officer Training March 2007 ”. Then, on the row below, enter Surname: Leave the cursor flashing after the colon. If the Field pick list is not already showing, click the button to bring it on screen. Select the ‘Text’ tab from the pick list. This then gives a short option list of ‘text’, ‘upper-case text’, and ‘encryption field’. For now we’ll accept the default ‘text’ option. Set the field length to 20, then click the Insert button. EpiData inserts a series of underscore characters after the Surname: label. Underscore characters _ are how EpiData denotes plain text fields. The number of underscores indicates the maximum length of the field. On the next line, type Forename: Using the field pick list again, insert another text field of 15 characters. Now let’s try a different field type – dates. On the next line, type Date of birth: Select the ‘Date’ tab from the field pick list. This presents two lists of options – general date fields on the left, and ‘automatic’ dates on the right. General date fields are formatted in three different ways. For most of us in Europe, the <dd/mm/yyyy> format is most natural, so select that. Click the Insert button, and EpiData inserts the relevant date format field type. On the next line, type Gender: and insert a single character Uppercase text field. EpiData inserts a <A> code, which denotes an uppercase field one character long. Later, we’ll restrict the entries in this field to either M (male), F (female) or U (unknown). Below this, add the label Occupation: and insert another 20 character text field. We need to be able to record interviewee address details. First, let’s create a house number field. On the next line type “ House number: ”, and then select the ‘Numeric’ tab on the field pick list. Select 3 digits before the decimal point, and 0 digits after it, then click the Insert button. EpiData inserts ### after the “House number:” label. # characters are how EpiData denotes numeric fields, and again the number of # characters indicates the maximum size of the number. (Numbers with a decimal point appear as ##.## ). 4 Creating a Questionnaire using EpiData Add another text field for House name (30 characters), and three more fields for Street name (30 characters), District (20 characters) and Town (20 characters). Then add another label for Postcode: and this time add an ‘Uppercase text’ field of 8 characters. EpiData inserts uppercase fields as <A > with the number of spaces determining the total length of the field. Finally, let’s add a field for telephone details. Initially it seems like a good idea to create this as a numeric field, but in doing this we wouldn’t be able to record any text details (such as ext. etc), and it’s unlikely we would ever want to order our data by telephone number, so it’s probably easier to simply create a text field of around 15-20 characters. If you prefer you can create two fields, one for home and one for other (e.g. work, mobile). We’ve now created the fields for the basic contact details of the interviewee. Before proceeding onto further work, let’s save what we’ve done so far. Click the Save button on the toolbar (or select File > SaveSave). Enter an appropriate filename and location in the dialog box, and click Save. We can also take a sneak preview of how the questionnaire will appear for those entering