An IDN, or integrated delivery network, is a healthcare organization that brings together hospitals, physician practices, outpatient clinics, and sometimes insurance plans under a single coordinated system. The goal is to manage a patient’s care across every stage, from a primary care visit to surgery to rehabilitation, within one connected network rather than through scattered, unrelated providers. As of July 2025, there are over 900 active IDNs operating in the United States.
How an IDN Is Structured
At its core, an IDN is formed when individual healthcare institutions affiliate with one another to operate as a unified system. A large IDN might include dozens of hospitals, thousands of physicians, specialty clinics, home health services, pharmacies, and even its own health insurance plan. Geisinger, for example, operates a 1,000-physician medical practice, six hospitals, and a health plan covering 500,000 members, all under one organizational umbrella.
Not every IDN looks the same. Some are built through horizontal integration, where organizations that provide similar services join together. A hospital system acquiring multiple hospitals in a region is horizontal integration. Others grow through vertical integration, where organizations at different levels of care merge. A hospital buying physician practices or adding rehabilitation facilities and home health agencies is vertical integration. Most large IDNs use both strategies, combining a broad geographic footprint of hospitals with a full spectrum of care services.
The Largest IDNs in the U.S.
The scale of today’s biggest IDNs is enormous. Based on net patient revenue data from 2025:
- HCA Healthcare: $56.3 billion
- CommonSpirit Health: $29.4 billion
- Kaiser Permanente: $29.1 billion
- Advocate Health: $22.5 billion
- University of California Health: $21.9 billion
These systems operate hundreds of facilities across multiple states. Kaiser Permanente is a particularly notable model because it combines hospitals, medical groups, and a health insurance plan into a single entity, meaning it both delivers care and covers the cost of that care for its members.
Why IDNs Exist
The traditional U.S. healthcare system is fragmented. Your primary care doctor, your specialist, your hospital, and your insurance company often operate independently of one another, with limited communication between them. This creates gaps: duplicate tests, conflicting prescriptions, lost records, and no single point of accountability for your overall health.
IDNs were designed to solve that problem. When every provider works within the same network, they share a common medical record system, follow coordinated treatment plans, and have financial incentives aligned toward keeping patients healthy rather than simply treating each visit as an isolated transaction. The model is intended to be more efficient in a healthcare environment where costs continue to rise.
How Patients Benefit
The clearest advantage for patients is care coordination. When your primary care doctor, cardiologist, and surgeon all belong to the same IDN, your records, lab results, and treatment history flow between them without you having to carry paperwork or repeat your story at every appointment. Referrals happen internally, and handoffs between different levels of care are smoother.
Research backs this up in measurable ways. Studies on patients with depression treated within highly integrated programs found greater improvement in both physical health and mental health recovery compared to less coordinated settings. In one comparison, patients receiving collaborative care within an integrated system were significantly more likely to stick with their treatment (75% vs. 50%), rate their quality of care highly (93% vs. 75%), and report that their therapy was effective (88% vs. 63%). These kinds of outcomes reflect what happens when providers communicate and coordinate rather than working in isolation.
How IDNs Differ From ACOs
You’ll sometimes see IDNs mentioned alongside accountable care organizations, or ACOs, and the two concepts overlap but aren’t identical. An IDN is a structural arrangement: it’s a network of owned or affiliated healthcare facilities operating as one system. An ACO is a payment and accountability model, often tied to Medicare, where a group of providers agrees to take responsibility for the cost and quality of care for a defined population of patients. An IDN can function as an ACO or participate in ACO programs, but it doesn’t have to. Some IDN leaders have described their organizations as “beginning to act like an ACO” without formally adopting that label. The key distinction is that an IDN is defined by its organizational structure, while an ACO is defined by its financial and quality commitments.
Challenges IDNs Face
Building a truly integrated system is far harder than drawing an organizational chart. One of the biggest obstacles is technology. Many healthcare providers still operate with a mix of digital and paper systems, essentially layering expensive new technology on top of outdated processes. Despite more than 25 years of effort toward health information technology interoperability, the ability for different systems to seamlessly share patient data remains an unfinished project. Resistance to adoption among providers stays high.
Cultural alignment is another major hurdle. Merging hospitals and physician groups that have operated independently for decades means changing deeply ingrained workflows, clinical habits, and professional identities. Providers at every level need to buy in, and the benefits of integration aren’t always immediately obvious to staff dealing with day-to-day patient care. Transformational change at this scale requires shifts in organizational culture and individual mindsets, and those shifts are inherently difficult to manage because the outcomes are uncertain and human dynamics are unpredictable.
Financial incentives can also work against integration. The U.S. third-party payer system sometimes rewards volume over value, meaning providers earn more by performing more procedures rather than by keeping patients healthy enough to avoid procedures. This creates tension within IDNs that are trying to coordinate care efficiently while still maintaining revenue. And perhaps the most fundamental challenge is defining what “patient-centered care” actually means in practice. Research has found that healthcare providers often have a systematically distorted understanding of the patient experience, with provider perceptions differing drastically from what patients actually go through.
What This Means If You’re a Patient
If you receive care within an IDN, you’ll likely notice that your providers share the same electronic health record, that referrals to specialists stay within the network, and that your insurance (if offered through the IDN) is designed around the system’s own facilities. This can simplify your experience considerably, especially if you’re managing a chronic condition that involves multiple doctors and regular follow-up.
The trade-off is that IDNs typically encourage you to stay within the network. Going outside the system for care may mean higher out-of-pocket costs or less coordination. If you live in a region dominated by a single IDN, your choices may be limited. In areas with competing systems, though, IDNs often invest heavily in patient experience and convenience to retain members, which can work in your favor.