A new study has found that artificial intelligence systems propose medical tests and treatment plans that are more than three times as expensive as those recommended by doctors.
The finding comes from research published in NEJM AI and reported by the BMJ, which found a striking cost gap between AI-generated clinical recommendations and those made by human doctors. The study suggests that deploying AI as a diagnostic or treatment-planning tool could place considerable financial pressure on health systems — including the NHS — if its suggestions were followed without clinical oversight.
The research evaluated 24 AI systems, though the specific models were not all individually named, and compared AI outputs directly against doctor recommendations across a range of medical scenarios. In each case, the AI tended to favour more tests, more interventions, and more expensive treatment pathways. The cost difference was not marginal — it was more than threefold.
That’s a gap that matters. Health budgets are finite, and clinical decision-making has always had to weigh benefit against cost. If AI tools routinely push toward the pricier end of the spectrum, that raises real questions about how — and whether — they should be used to guide patient care.
The research adds to a wider debate about the role of AI in medicine. Supporters argue these tools can catch conditions that might otherwise be missed. But this study points to a potential downside: AI systems may not be calibrated to account for cost-effectiveness, which is a central part of how the NHS decides what treatments to offer.
On top of that, the BMJ has not called for AI to be removed from clinical settings, and the study does not suggest that more expensive automatically means worse. Yet the findings do indicate that human clinical judgement remains an essential check on AI recommendations, rather than something AI can straightforwardly replace.
Patients with questions about their own tests or treatment plans should speak to their GP or call NHS 111.
Source: @bmj_latest