1️⃣ A variable is defined as an ability to vary or subject to variation. In research any parameter that has the ability to vary influences results. This holds true specifically in healthcare and clinical research wherein a patient parameter that is variable impacts several health related attributes and outcomes.

2️⃣ In statistics, a variable is defined as an attribute of an object of study and is applied in healthcare for patient attributes. These variables for patients include demographic information such as age, gender, race/ethnicity, education, socioeconomic status, and geographic location, as well as clinical information such as medical history, comorbidities, lifestyle factors, and genetics.

3️⃣ Patient variables are an important source of information and help identify similarities and dissimilarities in sample populations. It helps to stratify patients based on variables that are similar and aids to identify and address health disparities, and improve patient outcomes. Researchers use patient variables in healthcare studies to identify factors that may influence health outcomes and to develop and test interventions to improve patient care.