The American Medical Association (AMA) has been quite transparent about its commitment to preventing America’s health care consumers from choosing to get care from non-physician health care professionals. The organization actively opposes legislative attempts to expand non-physician health providers’ “scope of practice.” It has long fought against state laws that permit nurse general practitioners (NPs) and board-certified family practice nurse practitioners (FNPs) from providing primary care independently from medical doctors, arguing that it would lead to higher costs and reduced safety for patients. It is hypocritical for an organization representing professionals who swear an oath to respect patients’ autonomy to presume to control patients’ choices of health care providers.

Last week the AMA trumpeted a new working paper published by the National Bureau of Economic Research that concludes, “Nurse practitioners (NPs) delivering emergency care without physician supervision or collaboration in the Veterans Health Administration (VHA) increase lengths of stay by 11% and raise 30-day preventable hospitalizations by 20% compared with emergency physicians.” The study used quasi-experimental variation to study the patient outcomes and utilization costs between nurse practitioners and emergency physicians rendering care to patients in Veterans Health Administration hospital emergency departments from 2017 to 2020. The authors conclude:

We use the quasi-random arrival of patients at the ED between times that may differ in the availability of NPs on shift, which drives the probability of being treated by an NP versus a physician. Compared to physicians, NPs incur greater resource costs to treat patients but achieve worse patient outcomes.

The study found that “lower productivity” was the primary contributor to higher costs—NPs tended to order more tests and consult medical specialists more frequently on patients they saw in the emergency department than emergency physicians. This often led to delays in admitting the patients to the hospital, contributing to poorer outcomes.

The AMA news report stated, “Overall, the study shows that NPs increase the cost of ED care by 7%, or about $66 per patient. Increasing the number of NPs on duty to decrease wait times raised total health care spending by 15%, or $238 per case.”

Even if emergency physicians provide more cost-effective and better-quality care to emergency patients than NPs, improving access to emergency medical care by adding NPs to the provider workforce might make the tradeoff worthwhile.

But the study’s authors—and the AMA news report—missed the Easter egg in the study’s conclusion section:

We show that the performance gap between NPs and physicians narrows as NPs gain more experience, suggesting that differences in training could explain some of the gap.

The study compares apples to oranges. Unlike many states, the VHA does not require nurse practitioners to be emergency certified (ENP), so most are FNPs trained to practice family medicine, not emergency medicine. A survey of NPs working in emergency care found that 78% were certified as FNPs and in 2020 only 0.9% of NPs were emergency certified, according to the American Association of Nurse Practitioners (AANP).

Since emergency care includes adult and pediatric primary care, critical care, and behavioral medicine, there is wide variability in the requirements for emergency NPs. On the other hand, most physicians who work in hospital emergency departments are specialists certified by the American Board of Emergency Medicine. Physicians eligible to take the certification exam must have completed postgraduate training (a residency program) in emergency medicine.

Had this study compared utilization costs and patient outcomes from emergency care rendered by board-certified emergency physicians to physicians trained in family medicine, it might have found disparities like those found with FNPs and ENPs.

Board-certified general surgeons may be quite competent in rendering care to patients in the ED with acute surgical emergencies but are less likely to compare well to board-certified emergency physicians when managing non-surgical emergencies, such as chest pain, shortness of breath, stroke, or a hypertensive crisis.

The AMA news report did not mention a study from the Netherlands that found no difference in diagnostic and clinical outcomes or waiting times for treatment between patients seen by ENPs and patients seen by junior or senior “house” physicians.

Those seeking an accurate apples-to-apples comparison can review the study we reported last month. This study also employed a quasi-experimental approach to maximize randomization and compared NPs to physicians providing primary care to more than 800,000 patients in the VHA system from 2010 to 2012. It concluded:

[T]his study shows that NP patients did not differ from MD patients in VA health care costs, but had less utilization of primary care, specialty care, and inpatient services.

Further, NP and MD reassigned patients achieved similar quality of care in chronic disease management. This study supports the evidence that use of NPs can improve access to primary care with similar quality and cost of care.

The VHA emergency medicine study that the AMA is touting makes no case against NPs and FNPs independently providing primary care. However, its findings do suggest that hospitals should prefer board-certified ENPs to FNPs when staffing their emergency departments with non-physicians.

Spencer Pratt is a Research Associate in the Department of Health Policy Studies