When Dave Rossi visited Breckenridge, Colorado, in the summer of 2001, he intended to stay for a season and then return to California. But Summit County’s mountain lifestyle lured him into staying. He set up his own design and marketing business and built a life full of mountain biking, hiking, skiing and other outdoor pursuits. As a self-employed business owner, the fit 51-year-old buys his own health insurance on Colorado’s insurance exchange. “My joke is that it’s my very expensive flu shot,” Rossi said. Typically, a flu shot is all the medical attention he needs in a given year.

That flu shot has only gotten more expensive. Despite his good health and scant use of health care services, Rossi’s insurance premiums have skyrocketed. In 2016, he paid $294.39 for an individual ACA plan with a $5,000 deductible. For 2018, Rossi is facing a monthly premium of $753 for a silver plan that has a $4,500 deductible. He’s not alone: Insurance premiums for ACA plans in Summit County rose an average of 32 percent for 2018 over the previous year.

Rossi is butting up against what some in Colorado call the “Summit County paradox.” The county has the nation’s lowest mortality rate but also some of the most expensive health insurance premiums in the marketplaces created by the Affordable Care Act. And it’s not just Summit. The No. 2 and 3 counties on the list of lowest mortality — Pitkin and Eagle counties (home to Aspen and Vail, respectively) — are also Colorado mountain communities with some of the nation’s highest health insurance premiums for people buying their insurance on an ACA exchange, despite having some of the state’s (and the nation’s) best health outcomes, with low rates of smoking and obesity. The 2018 unsubsidized lowest-cost bronze premium for a 40-year-old in Summit, Eagle and Pitkin counties is above the 95th percentile relative to the rest of the country, said Amy Jeter, a communications officer at the Henry J. Kaiser Family Foundation.

Insurance premiums are rising across the nation, and the blame is sometimes put on the high cost of insuring sick people. But the situation in Summit County suggests that simply getting people healthier isn’t enough to lower insurance costs. As we remain mired in a seemingly endless health care debate, there’s a lesson there for the rest of the country, too.

Rossi said that Obamacare’s increases are unsustainable for him because he can’t pass on those skyrocketing costs to his customers. Also, he earns too much income to qualify for subsidies that keep insurance more affordable. Health insurance premiums are rising so steeply that he has started wondering whether he should quit his business and look for a job that would offer insurance. “It’s a conversation I’ve been having with a bunch of friends and colleagues over the past couple of weeks,” Rossi said. “What are we going to do?”

Health care premiums are generally higher in places that have only one insurance carrier. But that’s not the case in Summit County, which has three insurance providers and 37 plans available on the 2018 exchange. “It’s something we’re scratching our head about,” Summit County Commissioner Dan Gibbs said. “It’s a crisis situation for many working families who can’t afford health insurance now.”

Colorado legislators know that something has gone wrong in the mountains — their outraged constituents have let them know as much — and as one of the states that created its own ACA health insurance exchange, Colorado has been very hands-on in managing the program. In 2014, the legislature sought to unravel the state’s health care cost conundrums by convening the Colorado Commission on Affordable Health Care. The committee found two major factors contributing to high costs in mountain communities using the ACA marketplace: a steeper cost to deliver care and a higher use of that care.

The cost of medical services was about 32 percent higher overall in the insurance region that includes the mountain resorts than it was in Denver, and for some things, it was much higher. Outpatient mental health services, for example, were 260 percent higher than those in Denver.

“It isn’t because the providers in these communities are making a fortune. It’s that the cost to run a hospital or medical practice in these areas is higher in those communities than in a place like Denver,” said Bill Lindsay, who chaired the commission. The high cost of living in places like Breckenridge, Vail and Aspen makes the problem worse because rents are more expensive and employees command higher wages.

The rural, isolated nature of these mountain communities also spikes the prices. Hospitals face high overhead costs to provide things like personnel, emergency facilities, expensive equipment and specialists. “In an urban setting, those costs can be spread over a large number of patients,” said Jonathan Mathieu, chief economist at the nonprofit Center for Improving Value in Health Care. In rural areas, these costs are spread over a smaller patient population. Hospitals in mountain resort areas also face the costs of “surge capacity” — preparing for an influx of population during the tourist season, said Chris Tholen, vice president of financial policy for the Colorado Hospital Association. “When ski season is in effect, hospitals have to open wings to care for winter ski injuries, but then we see those same wings closed for other months of the year,” said Tholen, who also served on the cost commission.

Rural areas across the country also have fewer providers and facilities like hospitals and imaging centers, and that lack of competition puts hospitals and providers in the catbird seat, Mathieu said. “You either deal with those suppliers, or as a payer, you’re not able to provide your customers those services. I think that’s a big part of this story.” When there’s only one hospital serving the county, insurance companies have more limited negotiating power. “There’s a snowball effect where it all adds up to higher cost of care,” Mathieu said.

But the cost of medical services isn’t the entire story. “When we dug into the details, we found that in the mountains, although you have a relatively young, healthy population, the utilization of certain services was 200 to 300 percent higher than for the same services in Denver,” Lindsay said, referring to advanced imaging and laboratory and pathology services.

The extra use of the health care system isn’t because all these mountain types are getting into bike wrecks or ski accidents that send them to the hospital for orthopedic injuries. Instead, Lindsay said, it’s about how many services people in mountain communities use — things like medical tests and advanced imaging like MRIs. Patients in Summit County’s insurance rating region use advanced imaging procedures at about three and a half times the rate that people in Denver do, and they’re not just using these imaging procedures to scrutinize broken bones or achy tendons but across the board, for things like cancer, too.

The commission couldn’t figure out why people in mountain communities get more advanced imaging services than people in urban areas like Denver, but it ultimately comes down to doctors. “It’s physicians who write the prescription,” Lindsay said. “The question is, why would the physicians be basically overprescribing? That’s a really important question, and I don’t know the the answer. But we need to figure out what the dickens is going on.” Why are such healthy people using so much care?

It could be that doctors in these regions were simply trained to do more testing. Edmond Toy, director of the Colorado Health Institute, said if that’s the case, “what you really need to do is have the physicians get the data in front of them and let them understand why this doctor tends to do more of this kind of procedure than the other and what they can learn from that.”

A less innocuous explanation for the high use of testing is that there are economic incentives to do more procedures, Toy said. If you buy an expensive MRI machine and you’re in a small community, that means you have to send almost everyone through if you want to recoup the cost. Whether this is what’s happening, though, remains unclear without more granular data.

It’s also possible that residents in mountain towns are using more care not because they’re sicker but because they’re richer and more demanding, Toy said. It’s just a hypothesis, but it could explain some of the disparity.

The one thing the Colorado commission’s report made clear is that the cost conundrum doesn’t have a single cause, and that means it doesn’t have a simple solution, either. But the situation in Summit County does offer lessons for the ongoing health care debate in this country: If we want to make health care affordable, it’s not enough to get people healthier — we also have to tackle the high cost of care and the potential overuse of expensive interventions.

Additional reporting by Anna Maria Barry-Jester.