If health startups want to solve America’s healthcare crisis they need to start building solutions for the one percent. I don’t mean income; I mean the most expensive individuals in the system. The ones who consume the most healthcare dollars. If you can dramatically decrease the cost of caring for the sickest Americans – or prevent users from one day falling into that category – you’ve cracked the case. If not, you’ll barely make a dent.

The Healthcare Costs Crisis in a Nutshell

That’s thanks to the staggeringly unequal distribution of health spending in the U.S. (more on that in a minute). But first, here’s the problem in a nutshell. Healthcare costs are rising in the U.S., as they are elsewhere, except that our nation has the highest per capital healthcare spending of any industrial nation. Remember the budget deficit you always read about? By and large, that’s a function of healthcare costs. Find a way to contain Medicare and Medicaid spending and you’re most of the way to putting the nation on a secure fiscal path.

But it’s not just a question of the federal coffers. Rising healthcare costs are taking up a greater and greater share of the nation’s wealth, effectively crowding out other spending. It’s fine for us to choose to spend more on healthcare as we get richer, except that it’s far from clear that we’re getting what we pay for.

Chronic Disease (Including Obesity, Diabetes, and Heart Disease) Drives Costs, And a Few Behaviors (Smoking, Drinking, Exercise, Eating) Drive Chronic Disease

Five percent of of the U.S. population accounts for 50 percent of health expenditures. Twenty percent of the population accounts for 80 percent of spending. Perhaps more than any other statistic, this distribution is central to thinking about how one might solve the dilemma of rising costs.

The bulk of that can be attributed to “chronic diseases,” non-communicable ailments that don’t go away on their own, and which account for more than 75 percent of U.S. healthcare spending. That category includes cancer, but it also includes several eminently avoidable conditions like obesity, diabetes and heart disease.

And the key to preventing a number of these conditions can be boiled down to just a few things, according to the Centers for Disease Control and Prevention (CDC):

Four common, health-damaging, but modifiable behaviors—tobacco use, insufficient physical activity, poor eating habits, and excessive alcohol use—are responsible for much of the illness, disability, and premature death related to chronic diseases.

So there it is. Want to crack healthcare costs? Help at-risk individuals smoke less, drink less, exercise more and eat better.

Can Health Apps Make a Dent?

Numerous consumer health startups are already tackling these behavioral triggers, including several in Boston. RunKeeper and Pact are encouraging exercise. Laveem, a recent TechStars Boston grad, is trying to encourage healthier eating. Ginger.io is helping to improve treatment of diabetes.

But there’s a problem. In several of these cases, the users aren’t the ones who really matter from a cost perspective. Think of the average RunKeeper or Pact user. They might not be a high level athlete, but they’re also unlikely to be high risk for chronic diseases.

This tension was nicely captured in a post at The Atlantic by Kanyi Maqubela, an entrepreneur in residence for the Collaborative Fund, back in March. Maqubela warned that health and fitness apps were being built for users similar to those creating them, and noted:

According to research at the John D. And Catherine MacArthur Foundation, “a large body of evidence indicates that socioeconomic status is a strong predictor of health. Better health is associated with having more income, more years of education, and a more prestigious job, as well as living in neighborhoods where a higher percentage of residents have higher incomes and more education.”

That point was captured in a New Yorker article from 2011 by surgeon and writer Atul Guwande about “hot spots,” concentrated areas of very sick people, usually in poor neighborhoods.

If health startups want to make a dent in the behavior that drives chronic disease, hot spots are where they need to go.

Working With the Healthcare System

Since sick and at-risk people are unlikely to be early adopters, health and fitness apps will need to tie into the healthcare system if they’re going to actually put a dent in costs. Steve Kraus of Bessemer Venture Partners believes that health entrepreneurs can pull it off, however.

“One of the challenges, though, in creating a product in the healthcare IT space is that there are a lot of different constituencies who may use or be affected by your product or service – doctors, hospitals, payors, patients, patient’s families, etc., etc.,” Kraus told me by email.  “Entrepreneurs really need to think about how they tailor their offering to meet the financial, clinical, and workflow needs of these different constituencies. We believe companies that figure out a way to provide a ‘win’ to each of these stakeholders will be highly sought after and highly effective in the marketplace.”

This doesn’t mean RunKeeper, Pact and Laveem all owe it to the world to run out and get deals with hospitals. When I asked RunKeeper about this question back in March, it pointed to its API as a way for others to innovate on top of its platform in ways targeted at users across the socioeconomic spectrum. That kind of openness could eventually be key in leveraging the RunKeeper app to curb obesity.

Ultimately, for entrepreneurs, activists, or politicians looking to startups and entrepreneurship to solve the nation’s health costs crisis, the specter of chronic disease looms large. The challenge is connecting behavior modifying innovation to the hot spots that need it.