By Victoria Bailey

Nurse practitioners (NPs) use more medical resources but achieve worse patient health outcomes compared to physicians, highlighting the productivity variations between the two professions, according to a working paper from the National Bureau of Economic Research (NBER).

Expanding the scope of practice for NPs is a widely debated topic in the healthcare industry, with proponents and opponents on both sides.

Granting full practice authority to NPs allows them to practice without physician supervision. This can help expand healthcare provider capacity during workforce shortages, but some experts worry that it can lead to higher costs and worse patient outcomes.

While NPs and physicians may perform similar tasks, they experience different training and incomes.

The Veterans Health Administration (VHA) granted full practice authority to NPs in December 2016. Researchers used administrative health records to assess a sample of 1.1 million emergency department (ED) visits and compare productivity differences between physicians and NPs.

They found that NPs had higher medical resource utilization but achieved less favorable patient outcomes. Cases treated by NPs had lengths of stay that were 11 percent longer and ED costs that were 7 percent higher. This translates to an 18-minute increase in length of stay and a $66 increase in cost per ED visit.

In addition, NPs were associated with a 20 percent increase in 30-day preventable hospitalizations compared to physicians. This could reflect poor decision-making by NPs about whom to admit to the hospital, leading to under-admissions of patients who should have been admitted, thus resulting in return hospitalizations.

Hospital admission rates and impacts on 30-day mortality did not differ significantly between NPs and physicians except regarding severe cases, where both measures increased for NPs.

These findings show that NPs exhibit lower productivity than physicians in ED settings. However, researchers noted that reducing the amount of care provided by NPs could still compromise patient outcomes.

The productivity gap between the two professions may be explained by varying experiences and training, different skill levels, and differences in patient populations, according to the paper.

NPs and physicians undergo different training, with the number of years of training for NPs equaling around half of what is required for physicians.

More experience for NPs minimized the productivity gap between physicians and NPs for several measures, including performance, costs, and CT ordering, researchers found. However, experience did not reduce the gap in 30-day preventable hospitalizations.

Lower diagnostic skills may increase providers’ use of consults and radiology tests. The study found that NPs were more likely to use consults and order CT scans and X-rays than physicians

“These results suggest that NPs are more likely to collect resource-intensive information from external sources than physicians are,” the paper stated. “This could directly increase lengths of stay as well as medical costs, since consults and diagnostics take time and resources to complete. On the other hand, consults and diagnostics allow lower-skilled providers to improve decision-making by incorporating more information and interpretation from other experts.”

Researchers also determined that NPs’ impact on patient outcomes was worse for more complex and severe cases.

“If NPs are less skilled at treating more complex or more severe cases, they may obtain worse patient outcomes for these cases,” they wrote. “On the other hand, as NPs increase their intensity of care for these cases, the incremental care could mitigate the NP effect on raising preventable hospitalizations.”

Many medical assocations maintain that expanding NP scope of practice threatens patient safety and raises costs, claiming that NPs’ skills are not interchangeable with fully trained physicians.

However, many patients and providers are advocates for broader NP authority. A poll conducted on behalf of CVS Health found that 82 percent of patients and nearly 80 percent of healthcare providers supported expanding the scope of practice for NPs.