A Health Affairs Study Found That Corporate-Affiliated Fee-Based Primary Care Grew 576 Percent From 2018 to 2023. About 60 Percent of the Clinicians in the Study Bill Medicare.

Analysis by DPC Insider — Research Desk
#research#corporate ownership#concierge medicine#physician independence#Health Affairs#market structure
Sources: Growth In Number Of Practices And Clinicians Participating In Concierge And Direct Primary Care, 2018–23 — Health Affairs · Fee-based primary care is rapidly rising in U.S., hastening doctor shortages for public — JHU Carey Business School, December 18, 2025 · Concierge medicine rising, Hopkins research finds — JHU Hub, December 18, 2025 · 2026 State of Direct Primary Care Report — DPC Alliance · Concierge and direct primary care are booming, but corporatization and access questions are close behind — Physicians Practice · Concierge and DPC Practices Grow 83% in 5 Years — Harvard Medical School

When researchers from Johns Hopkins and Harvard counted fee-based primary care practices in 2023, they found that about one in three was corporate-affiliated. In 2018, it was about one in eleven.

Those numbers come from a Health Affairs study published last December. A team from the Johns Hopkins Carey Business School, the Johns Hopkins Bloomberg School of Public Health, Oregon Health & Science University and Harvard Medical School used a national online directory to identify practices charging flat membership fees for primary care services, then linked those sites to NPI records and billing data. Over five years, practice sites grew by 83.1 percent and the number of clinicians in them grew by 78.4 percent. Corporate-affiliated practices grew by 576 percent. Independent ownership fell from 84 percent to roughly 60 percent.

The study received press coverage from Hopkins in mid-December, and subsequent coverage in healthcare trade publications has prominently cited the 576 percent figure. There is a specific number in the study, though, that changes how you read that figure.

The Medicare Signal

About 60 percent of the clinicians in the Health Affairs database participated in Medicare billing.

Standard DPC practices don’t bill Medicare. The DPC Alliance defines the model around the absence of insurance billing for clinical services: a flat monthly membership fee, full stop. A physician who accepts Medicare assignments for patient visits is running something structurally different from independent DPC, even if the practice also charges a membership fee. That’s the concierge model: premium access plus insurance billing.

The 60 percent Medicare participation rate in the Health Affairs data is a strong signal that the majority of clinicians in the study are in concierge or hybrid practices, not independent DPC. The authors acknowledged this limitation: they were unable to systematically distinguish between the two models on the basis of third-party insurance billing. Practices were identified through a directory and then linked to billing records; the Medicare participation rate was derived afterward, and the method captures both models without a flag separating them.

That is a defensible methodological choice for measuring the total market. It means the headline numbers describe a combined category, and the corporate growth signal may be coming primarily from the concierge tier.

Where Corporate Growth Is Coming From

The combined fee-based primary care market the study tracks includes both concierge practices, which pair membership fees with continued insurance billing, and independent DPC practices, which operate entirely outside the billing system. If corporate-affiliated growth is concentrated in the concierge tier, that would fit the study’s own data, but the data cannot confirm it, since both models share the same category.

Independent DPC built differently: solo and small-group physicians who left the billing system, opened practices they owned, and signed up local patient panels at monthly fees the 2026 DPCA report pegs at a national average of $98.64 across all practice categories. The DPC Alliance’s 2026 physician survey, drawing on responses from 465 physician respondents, found that 82.4 percent held full ownership of their practices.

That is a meaningfully different picture from the Health Affairs finding that about one in three practices in the broader fee-based primary care market is now corporate-affiliated. The DPCA number and the Health Affairs number are measuring different populations. The former draws from physicians who responded to a DPC Alliance survey, a group that skews toward independent practitioners. The latter covers the full directory-identified market, which is weighted toward concierge medicine by the Medicare billing proxy.

The Clinician Mix Is Also Shifting

The Health Affairs study tracked workforce composition alongside ownership. In 2018, physicians made up 67.3 percent of the clinicians in fee-based primary care practices. By 2023, that figure was 59.7 percent. Advanced practice clinicians (nurse practitioners and physician assistants) rose to 40.3 percent of the workforce.

Concierge networks expanding by adding NP and PA staff to physician-run sites is one possible explanation for that shift in the combined data. Whether the same staffing shift is happening in independent DPC at the same rate is not something the Health Affairs data can answer, for the same reason it can’t cleanly parse the ownership question: the two models are in the same database without a flag separating them.

The Health Affairs study is not wrong about the combined market. It found what it found. The risk is in how the headline numbers get translated: a 576 percent corporate growth figure for the combined category can read as a story about DPC specifically, even when the data describes the full market.

The Open Question

The study’s most important limit is the one its authors acknowledged: third-party insurance billing cannot systematically distinguish between independent DPC and concierge practices in the data.

A study that separated practices with zero insurance billing from practices that charge a membership fee and also accept insurance would give a cleaner read on whether independent DPC is experiencing the same ownership shift the broader market shows. The Health Affairs researchers acknowledged that gap explicitly.

The Health Affairs data establishes that the combined fee-based primary care category has corporatized substantially, with corporate-affiliated practices growing from roughly one in eleven to one in three over five years. Whether the DPC piece of that category is on the same ownership path, or whether the 576 percent corporate growth figure is almost entirely driven by the concierge portion of the combined market, is the question this research surfaced but cannot resolve.

For independent DPC physicians, the DPCA survey data and the Health Affairs market data are both real. They describe different slices of the fee-based primary care landscape, and neither one tells the whole story.