Each person is unique thanks to a multitude of factors, such as racial and ethnic backgrounds, age, genetics, chronic conditions, disease severity, gender, environment, and even personal preferences when it comes to health treatments. These and other factors make patients different and affect how they may respond to a certain treatment. For these reasons, while the “average patient” may respond best to a particular treatment, some patients may experience little to no benefit from it, so other treatment options may be best for them. These differences in how patients respond to treatments are known as “heterogeneity,” or “individual treatment effects.”
Heterogeneity matters because if a medical professional is providing a patient care based on how the “average” person fared on that treatment, then that patient might not be getting the most ideal treatment. It also matters because most insurance companies design their policies to meet the needs of the majority of people, so those who may respond differently may have a more difficult time getting other treatment options covered. Many groups that represent patients are concerned that comparative effectiveness research or value assessments could be used to block or restrict access to treatments that help some, but not “average,” people.