A variable is a patient parameter which can be measured or classified. Age, gender, height, death date are variables. So can be the colour of the eyes, the leukocyte count, or the date of surgery. They are the name of the columns in your Excel spreadsheet.
By default, the software will ask you basic information (variables) about your patient: identity, birth date, inclusion date, gender, date of the last consultation and if necessary, date of death.
You can create your own variables in EasyMedStat to customize your series.