There is little evidence supporting the safety and efficacy of physician associates (PAs) and anaesthetic associates (AAs) in the UK, a new rapid systematic review has found.
The review, by researchers from the University of Oxford and the London School of Hygiene & Tropical Medicine (LSHTM), is the most comprehensive UK-based analysis of peer-reviewed research into PA and AA roles to date. It was written to inform the ongoing government-commissioned Leng Review which is examining the effectiveness and safety of these roles in UK healthcare.
The research is published in The BMJ.
PAs and AAs are being rapidly introduced across the NHS as a solution to workforce shortages and funding cuts. However, many question if these roles will improve the challenges facing the NHS and whether the training students receive is sufficient – two years following an undergraduate degree, in contrast to the five years it takes doctors to qualify and the additional ten years it takes to specialise.
The study found little evidence supporting the effectiveness and safety of the PA and AA roles, with almost no research on patient safety and many studies involving fewer than ten PAs. Key findings include:
Research on PAs and AAs in the UK is very limited
Only one small study assessed the competence of PAs through direct observation and no studies directly assessed the safety of AAs**.** Few of the studies screened for this research were of sufficient quality and relevance to current NHS policy and many studies were small, outdated, or lacked rigorous methods, making it difficult to assess the safety, effectiveness, or impact of PA and AA roles.
Safety concerns remain unaddressed
No research examined safety incidents or prescribing safety and there is no robust evidence assessing PA and AA roles in managing high-risk or complex patients.
What evidence exists is limited to a few settings
There was some preliminary evidence that PAs could support hospital ward teams and emergency departments when undertaking carefully circumscribed roles and closely supervised. However, evidence suggests PAs struggled in primary care, where the role is more autonomous and clinically complex. There is no direct evidence supporting the value of AAs in anaesthetics.
There is no evidence that deploying PAs or AAs improves efficiency or saves money
As a senior doctor is needed to oversee and check the work of PAs and AAs, this model may be more expensive than employing doctors.
Many patients were unaware they were seeing a PA
This lack of awareness raises concerns about transparency and informed consent.
Staff and professional bodies continue to express concerns
These bodies remain concerned about the scope of practice, supervision needs, and overall impact on medical training.
Professor Trisha Greenhalgh, lead author of the study and Professor of Primary Care Health Sciences in the Nuffield Department of Primary Care Health Sciences, University of Oxford, said:
“The expansion of physician and anaesthetic associates should be informed by solid empirical research. At present, we simply do not have the data to support claims that these roles improve efficiency or maintain patient safety. The absence of reported safety incidents in research studies does not mean they do not occur - it means we are not doing the right kind of research to detect and analyse them.”
Professor Martin McKee, co-author of the study and Professor of European Public Health at the London School of Hygiene & Tropical Medicine, said:
“The mismatch between policymakers’ enthusiasm for expanding these roles and the lack of rigorous research evidence should be a red flag. Workforce shortages are a real challenge, but they cannot be addressed by replacing doctors with people whose training maps poorly to the duties expected of them, and who may be inadequately supported, without a clear, evidence-based strategy.”
The study calls for a national scope of practice for PAs and AAs, informed by rigorous research into their safety, efficacy, and cost-effectiveness. Specifically, it urges:
A systematic investigation into safety incidents involving PAs and AAs
Robust studies evaluating their impact on patient outcomes
An assessment of the hidden costs and inefficiencies associated with their deployment
Clear national guidelines defining their roles and limits, based on a detailed understanding of what their training prepares them for, especially in complex cases
As the Leng Review deliberates on the future of these roles in the NHS, this study provides a crucial evidence-based perspective. The authors hope it will help shape a more informed, balanced approach to workforce planning and patient safety in UK healthcare.
This story is based on an original press release from the University of Oxford.
Publication
Greenhalgh, McKee, Physician associates and anaesthetic associates in UK: rapid systematic review of recent UK based research, The BMJ. DOI: 10.1136/bmj-2025-084613