  Recent studies have demonstrated promising performance of ChatGPT and GPT-4
on several medical domain tasks. However, none have assessed its performance
using a large-scale real-world electronic health record database, nor have
evaluated its utility in providing clinical diagnostic assistance for patients
across a full range of disease presentation. We performed two analyses using
ChatGPT and GPT-4, one to identify patients with specific medical diagnoses
using a real-world large electronic health record database and the other, in
providing diagnostic assistance to healthcare workers in the prospective
evaluation of hypothetical patients. Our results show that GPT-4 across disease
classification tasks with chain of thought and few-shot prompting can achieve
performance as high as 96% F1 scores. For patient assessment, GPT-4 can
accurately diagnose three out of four times. However, there were mentions of
factually incorrect statements, overlooking crucial medical findings,
recommendations for unnecessary investigations and overtreatment. These issues
coupled with privacy concerns, make these models currently inadequate for real
world clinical use. However, limited data and time needed for prompt
engineering in comparison to configuration of conventional machine learning
workflows highlight their potential for scalability across healthcare
applications.
