Mission Creek Apartments is senior-only supportive housing facility in San Francisco. (Photo courtesy of Mercy Housing)

When I met Alvin in the mid-2000’s, he looked much older than his 67 years. Exposure to trauma and an underlying mental illness led to drug addiction and other health issues, and kept him cycling in and out of jail, prison, hospitals, and shelters for many years. Housing him took a concerted effort by dedicated case managers and medical staff, but after he moved in to a senior-only, permanent, supportive housing unit, his drug use—and use of hospital services—diminished. The difference in health care costs between the year before he was housed and the year after was enough to pay for his housing for the next 15 years and very likely contributed to extending his life.

As a primary care physician who has worked with San Francisco’s homeless population for more than 25 years, I know firsthand how important housing is to health. Multiple studies have shown how housing improves the health of people living with homelessness and the extremes of poverty. One study we conducted at the San Francisco Health Department among homeless people with AIDS showed that housing with on-site services reduced mortality by 80 percent over a five-year period. No other health care treatment among homeless adults can show anywhere near such an impact on mortality.

In addition, as Alvin’s story illustrates, offering housing is often the most cost-effective health care treatment available. Yet, despite the proven benefit of housing, the US health care system rarely invests in it. Even in Los Angeles, where the county Department of Health Services (DHS) is leading one of the largest expansions of permanent supportive housing in the country (10,000 new housing units over the next five years), only 0.3 percent of the DHS annual budget goes toward housing. As the US government continues to underfund public housing (only one in four Americans who qualify for affordable housing get it), the number of homeless adults continues to increase across the country.

Concerns like these and the intense debate about US health care has left many Americans feeling anxious about the future. However, a handful of communities around the country, where the health care system is investing in housing and bucking national trends, provide a roadmap to hope. Even though federal regulations prohibit the use of Medicaid funds toward “room and board,” these communities have found ways to invest health care resources in housing. The nine cases we documented in a recent report (produced by the Low Income Investment Fund and Mercy Housing, with funding from the Kresge Foundation and the California Endowment) have a few common attributes, including adherence to strict fiscal constraints and increased patient autonomy—something politicians on both sides of the aisle can get behind.

One example of a robust investment in housing as an alternative to institutional care is the Community Care Settings Pilot of the Health Plan of San Mateo (HPSM), a nonprofit Medicaid managed care organization (MCO) in Northern California. HPSM wanted to give low-income, disabled members living in nursing homes more options when it came to where they lived. Many members didn’t need to live in nursing homes, but did, due to system inefficiencies. The organization has so far successfully moved 124 people from nursing homes to independent housing with supportive services, where they have much more choice in terms of how they spend their time, what they eat, and so on. After leaving the nursing home, these individuals not only reported much greater life satisfaction, but also used significantly fewer health care resources. Members’ health care costs (including the portion of housing costs the MCO paid) were 50 percent lower in the six months after the move than in the previous six months, saving the health plan $2 million over that time.

Meanwhile, the Centers for Medicaid and Medicare have encouraged innovations that adhere to the Triple Aim: lower cost, improved outcome, and improved access to care. A good example of a Triple Aim success is a local accountable care organization (ACO) in Minneapolis called Hennepin Health. Hennepin Health’s “housing navigators” connect adults with disabilities who are experiencing homelessness with housing vouchers they can use for rent, and—similarly to Harry Potter’s Sorting Hat—help people find housing that suits their needs. The result is reduced emergency room visits and improved health outcomes, such as glucose control for diabetics and fewer psychiatric hospitalizations for people with severe and persistent mental illness. By the end of 2017, it is expected that Hennepin County will achieve “functional zero” for chronic homelessness, meaning there is sufficient housing to provide an exit to homelessness for all adults who have been stuck on the streets.

Now that the Republican effort to repeal and replace the Affordable Care Act appears to be dead, Congress may be able to come up with real solutions to America’s health and housing crises. If it does, the nine communities we profiled can serve as models for other programs that address some of the root causes of illness among people living in poverty and on the streets.

Compared to other health care treatments that have similar impact on improving health, housing does not increase the size and cost of the health care sector. Just a few weeks ago, the Food and Drug Administration approved an exciting new treatment for a rare form of leukemia. As we revel in new opportunities for treatment that emerge from advances in science and technology, let’s not lose track of those who need access to basic needs to make progress against their illnesses. Medicaid cannot become the de facto agency for funding housing for those who need care. But it is important to recognize that housing—as an alternative to unnecessary utilization of hospital- and institutional-based care—is good medicine and can gain support across the political spectrum.