Physicians, nurse practitioners, and physician associates (PAs) enhance different aspects of patient care quality, a new Yale and Fair Haven Community Health Care study finds.

Researchers evaluated how each of these clinicians contributed to the quality of care in federally qualified health centers in the United States. The findings, they say, challenge assumptions that it is always better to staff with more physicians and highlight how strategic hiring could allow health centers to tackle specific health challenges in their communities.

The findings were published in JAMA Network Open.

The study emerged from a practical question, says senior author Benjamin Oldfield, an assistant clinical professor of internal medicine at Yale School of Medicine and the vice president of clinical affairs at Fair Haven Community Health Care, a federally qualified health center (also known as health centers) in Greater New Haven.

"We were initially interested in whether there was a magic clinician ratio between doctors, nurse practitioners, and physician associates that might be associated with the highest quality of care," said Oldfield.

Health centers, like the one Oldfield works in, provide care for 31.5 million Americans, many of whom live in poverty or are from minoritized racial and ethnic groups.

"Health centers are extremely important models of care for minoritized populations," said Oldfield. "If we can improve quality of care in health centers, that will have a significant impact on not only a large number of Americans, but also on a particularly vulnerable group of Americans for whom quality of care is especially relevant to health equity."

For the study, the research team—which included medical doctors, a nurse practitioner, and a graduate student—evaluated the staffing models of 791 health centers in the U.S.

They fell into five categories: balanced proportion of physicians, nurse practitioners, and PAs; more nurse practitioners than physicians; more physicians than nurse practitioners; roughly equal proportion of physicians and nurse practitioners; and large health centers (which had two to five times larger workforces than other health centers).

The researchers then looked at how well each of these staffing models performed on the 14 measures through which health centers are regularly evaluated.

"We found that higher performances on diagnostic-related measures like cancer screening and HIV testing were associated with staffing models with more physicians," said Oldfield. "But having more nurse practitioners and PAs was associated with better performance on health promotion metrics, such as obesity assessment, healthy eating counseling, and infant vaccinations."

These findings are valuable for health centers as they consider how to staff with limited funding. They could also help guide centers as they target specific issues in their communities, said Oldfield. For instance, pediatric obesity is a current health concern that, based on these findings, would benefit from a model that prioritized nurse practitioner staffing.

The study also offers support for making national initiatives aimed at encouraging clinicians to work in health centers, like student loan forgiveness incentives, equitable across different types of professional roles.

"That will be essential," said Oldfield. "Our findings suggest that all of these roles make critical and unique contributions to quality."