Mississippi has nearly three nurse practitioners for every primary care physician. That single ratio reframes a decade of assumptions about how the American healthcare workforce actually operates.

The Southeast Is Running a Different Workforce Model

The national conversation about NPs and PAs tends to treat them as a supplement to physician-led care. The data from Medicare enrollment records tells a different story in several states, particularly across the South.

Mississippi leads every state in the country: NPs and PAs make up 35% of its 12,583 total Medicare-enrolled clinicians, with 4,102 NPs and 308 PAs. Tennessee sits just behind at 34.8% of its 35,021 Medicare clinicians, including 9,669 NPs and 2,520 PAs. Kentucky ranks third at 33.2%. These aren't marginal differences from the national pattern. They represent a structural shift in who delivers care.

The NP-to-primary-care-physician ratio makes this concrete. In Mississippi, there are 2.96 nurse practitioners for every internal medicine or family practice physician, the highest ratio in the data. Kentucky is second at 2.60. Tennessee follows at 2.43. In these states, NPs aren't filling gaps around the edges of a physician-led system. They are the primary care system, at least by headcount.

Compare that to Florida, where the NP-to-PCP ratio is 1.60, or California, where NPs and PAs represent only 15.8% of 133,478 total Medicare clinicians. The gap between Mississippi and California isn't a rounding error. It's a 19-percentage-point difference in workforce composition, and it reflects fundamentally different approaches to care delivery across state lines.

Scale Doesn't Explain the Pattern

A reasonable assumption is that high NP/PA concentration is a small-state phenomenon, a workaround for states that simply can't attract enough physicians. The data partially supports that, but only partially.

North Carolina has 52,922 total Medicare clinicians, ranking it 49th by fewest clinicians, meaning it has one of the larger workforces in the country. Yet NPs and PAs represent 30.1% of that total, with 15,918 NP/PA clinicians, placing North Carolina 6th nationally by NP/PA share. Ohio tells a similar story: 59,669 total Medicare clinicians (50th by fewest, so among the largest workforces), with NPs and PAs at 29.2% and an NP-to-PCP ratio of 1.86.

Tennessee reinforces the point. It ranks 41st by fewest clinicians, meaning it has a mid-to-large workforce, yet its 34.8% NP/PA share puts it second in the country. High NP/PA penetration is not a small-state accommodation. It's a regional pattern that persists regardless of total workforce size.

What the Ratio Actually Measures

The NP-to-PCP ratio is the sharpest lens here because it captures substitution, not just addition. When Mississippi has 4,102 NPs and only 1,385 primary care physicians (656 in internal medicine, 729 in family practice), the workforce isn't structured around physician oversight in any practical sense. NPs are the primary point of contact for a large share of Medicare patients in that state.

For workforce analysts and quality researchers, this matters because most Medicare cost and outcomes models were built on assumptions about physician-led care. Those models may be measuring the wrong denominator in states where NPs outnumber PCPs by nearly 3-to-1.

Florida's contrast with Mississippi is instructive. Florida has 27,280 NP/PA clinicians representing 27.5% of its 99,353 total Medicare clinicians, while MD/DOs account for 47.2%. The physician share remains dominant. In Mississippi, that balance has already inverted in primary care. Whether patients in high-NP states are receiving equivalent, better, or worse care compared to patients in California, where NPs and PAs represent only 15.8% of clinicians, is the question that the enrollment data alone cannot answer, and the one that every workforce projection model now needs to ask.