A NEW rapid systematic review published last Friday 7th March by researchers from the Nuffield Department of Primary Care Health Sciences, University of Oxford, and the London School of Hygiene and Tropical Medicine, has found little evidence supporting the safety and efficacy of physician associates (PAs) and anaesthetists associates (AAs) in the UK.
This raises critical questions about the rapid expansion of these roles in the NHS.
The doctors’ union the British Medical Association (BMA) on Wednesday demanded an ‘end to PA postcode lottery after review concludes no evidence of their safety’.
It said: ‘The BMA is urgently calling on NHS England to introduce a mandatory scope of practice for physician and anaesthesia associates (PAs and AAs), following the publication of a systematic review which concludes there is a lack of evidence these roles are safe.
‘In November 2023, the BMA called for a national pause in the recruitment and expansion of PAs and AAs following evidence that they are working considerably beyond their competencies, taking on tasks that are usually undertaken by doctors with a decade or more of education and training.
‘Professor Sir Stephen Powis and Dr Navina Evans, NHS England’s National Medical Director and Chief Workforce Officer respectively, wrote an open letter at the time claiming: “The evidence tells us MAPs (Medical Associate Professions) are safe, increase the breadth of skill, capacity and flexibility of teams, positively contribute to patient experience and flow, and reduce workload pressure on other clinicians.”
‘Despite the BMA requesting the evidence for this claim at the time, none was provided.
‘In the BMA’s letter, sent yesterday (11 March 2025), chair of BMA council Prof Phil Banfield reminds them of this claim in light of the BMJ’s rapid review, which concluded that NHSE’s “conflating absence of evidence of safety incidents in a small number of research studies with absence of safety concerns … is an error of logic that is likely to cost lives.”
‘Banfield goes on to say: “By maintaining a postcode lottery in which different hospitals can decide what physician and anaesthesia associates can and can’t do in the absence of any agreed scope of practice, I fear that the NHS has created a patient safety scandal …
“It is wholly unacceptable for NHS England to continue its current course of inaction relying on evidence that cannot be provided and which this systematic review has shown does not exist.”
‘An increasing number of coroners are now raising concerns after several tragic deaths following misdiagnosis by PAs:
‘Emily Chesterton died following the misdiagnosis of a blood clot in 2022 by a PA she thought was a doctor.
‘Pamela Marking died in February 2025 after being wrongly diagnosed with a nosebleed by a PA when she had a strangulated hernia.
‘While the Secretary of State for Health and Social Care has now launched a review of the role, NHS England had refused to introduce interim safety measures to protect patients and the BMA has called upon them to review this position immediately.’
The research, published in the British Medical Journal (BMJ) and led by Professor Trisha Greenhalgh and Professor Martin McKee, 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.
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:
- 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 roled in managing high-risk or complex patients (for which their relatively limited training may not equip them).
- 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, raising concerns about transparency and informed consent.
- Staff and professional bodies continue to express concerns about the scope of practice, supervision needs, and overall impact on medical training.
Call for evidence based workforce planning
Professor 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, emphasises that the lack of evidence does not equate to proof of safety.
Greenhalgh states: ‘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,’ he said.
‘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,’ he concludes.
Professor McKee, co-author of the study and Professor of European Public Health at the London School of Hygiene and Tropical Medicine, echoes these concerns.
McKee said: ‘The mismatch between policymakers’ enthusiasm for expanding these roles and the lack of rigorous research evidence should be a red flag.
He added: ‘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.’
Implications for policy and the Leng Review
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.