What is the Origin of Indication Bias?

The concept originates from epidemiology and biostatistics, highlighting the methodological challenges of drawing causal inferences from non-randomized, real-world clinical data. The term emphasizes the confounding influence of the clinical 'indication' for treatment.

What is the Mechanism of Indication Bias?

For example, a clinician might only prescribe a specific hormone therapy to patients who are already healthier or have less severe symptoms, leading to an artificially favorable outcome for that treatment in an observational study. Conversely, if a therapy is reserved for the sickest patients, it may appear less effective or riskier than it truly is. Researchers must employ sophisticated statistical methods, such as propensity score matching, to attempt to decouple the effect of the treatment from the prognostic influence of the underlying indication.

Indication Bias

Meaning

Indication bias is a form of confounding that occurs in observational clinical research when the reason a patient is prescribed a specific treatment is inherently linked to the outcome being studied, independent of the treatment’s true effect. This systematic error arises because clinicians tend to prescribe a therapy based on a patient’s prognostic profile or severity of their underlying condition. It can falsely inflate or diminish the apparent effectiveness or risk of a therapy, such as hormone replacement, if not adequately controlled for in the study design.