Biases of large language models in diagnosing Cushing's syndrome.

The diagnosis of endogenous Cushing's syndrome (CS) can be complicated and often delayed, given its low incidence (estimated globally at 1.8 cases to 4.5 cases per million people per year) and its clinical features that mimic far more prevalent metabolic disorders, such as central obesity, hypertension, and glucose intolerance. In clinical practice, physicians rely on cognitive heuristics that are prone to error, contributing to diagnostic delays (on average around 34 months pass from symptom onset to diagnosis of CS). Large language models and machine learning algorithms could be potential decision-support tools for screening and differential diagnosis of CS. However, these systems are at risk of inheriting and even amplifying existing cognitive biases and data-driven distortions embedded in their training data. Machine learning models designed for CS could be vulnerable to methodological flaws, notably spectrum bias and the exclusion of clinically relevant demographic variables, demanding attention from the endocrine and medical informatics communities. This paper examines how cognitive and algorithmic biases intersect in diagnostic models for CS, highlighting parallels between human diagnostic heuristics (