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Research · 04 of 06

Where AI chatbots push overuse: small thyroid nodules and routine ECGs

AI chatbots mostly follow Choosing Wisely, but their errors cluster on the low-value tests clinicians already over-order.

Design
Benchmark evaluation of six commercial large language models
Population
225 scenarios from 15 Choosing Wisely recommendations; 4,050 responses
Primary outcome
Overuse rate and false restraint rate
Effect
Overuse 5.4% (0.6–12.2%); false restraint 0.6% (0.1–1.2%)

An Annals benchmark study tested six commercial large language models from three companies on 225 clinician-style scenarios built from 15 Choosing Wisely recommendations, generating 4,050 responses. In each set, restraint was appropriate in some scenarios and action in others.

Overall the models recommended overuse in 5.4% of responses and wrongly withheld an appropriate action in 0.6%. Overuse was concentrated: thyroid ultrasound for an incidental nodule under 1 cm in 42.8% of responses, and a routine ECG in low-risk adults in 28.3%. Most other recommendations were handled well.

Clinicians increasingly check decisions with these tools. The overall picture is reassuring, but the errors cluster in exactly the low-value tests clinicians already over-order, so a tool may reinforce a habit rather than correct it.

Use such tools as a second opinion, not a decision, and be most sceptical when one suggests a test.

  • Treat a chatbot's suggestion to order a test with more scepticism than a suggestion to hold off
  • Do not order thyroid ultrasound for an incidental nodule under 1 cm without a specific indication
  • Do not order a routine ECG in an asymptomatic low-risk adult
  • Note that this was a benchmark with single prompts, not real-world use

Why it matters

A decision aid can entrench overuse exactly where it is already most common.

Don't overread it

A benchmark with single prompts cannot show how these tools behave in a real consultation.

The statistics, in plain English

The overall overuse rate of 5.4% has a wide interval (0.6% to 12.2%) because it varied so much between recommendations; the average hides two clear trouble spots.

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