"Secondary prevention is identifying people who have a disease but don't show symptoms yet," he continues. "One great example of this that's common in the United States is cardiovascular disease; you can detect that before a patient ever shows symptoms by measuring blood pressure. Secondary prevention is early diagnosis and treatment to prevent progress of symptoms or ameliorate the course of disease.

"Tertiary prevention is preventing the progression of the disease. For example, if a patient with congestive heart failure has already had a heart attack, then you have to treat not only the immediate episode but also consider what you can do to prevent another one.

"Each of these categories has inherent cost issues," Nace notes, "because offering a preventive care program for everybody is different than offering it for a targeted group. And prevention and treatment overlap. If you're doing secondary prevention, measuring blood pressure in a patient who has cardiovascular disease and you don't know it – are you treating the disease, or are you preventing it?"

Although carriers are on the hook for covering preventive care in any plans they offer the public, it's clear there might be some disagreement about what constitutes prevention and what constitutes treatment. Furthermore, many experts note that preventive care is only successful when a patient is invested in his or her health – and that's not necessarily a given.

"A lot of payers and providers assume that when somebody's unhealthy, they want to get better," says Paul Schrimpf, an associate partner at Prophet. "Oddly enough, that's not always the case. Some people are less healthy than others: They smoke, they drink, they don't exercise, they figure everybody's going to die someday and they just don't care. People who are unhealthy and want to get better – those are the people who will be impacted by preventive care programs. It's not going to be healthy people who stay healthy or unhealthy people who don't care."

And sometimes, prevention simply doesn't work as hoped.

"We have a myth in the United States, and the myth is that illness is optional and that everything can be prevented," says Alan Spiro, MD, chief medical officer and chief health assistant at Accolade. "People get sick; it's part of the human condition. There are things you can do to stay healthier, and that fits into prevention. But there's a distinction between activities you can do on your own to decrease your risk of illness – diet, exercise, those types of wellness activities – and visiting a doctor for a routine screening."

"Not all preventive care is created equal," Schrimpf says.

There are, however, some measures that experts generally agree are beneficial for your health – and that can help save money for carriers in the long run.

"I think it's a very good idea from a preventive point of view to have a primary care physician and to see that doctor in some kind of regular way, making sure that there's some continuity and the doctor has a chance to get to know you," Spiro notes.

"Many of the activities that are really effective in terms of wellness don't have anything to do with medical costs," Nace says. "And many of these prevention activities are timespan-related in terms of cost-effectiveness for the health plan."

In other words, health plans will reap the most benefit from many prevention activities over an extended period of time – and there's no guarantee that the insured will stay enrolled with the health plan that generated the prevention program.

"When it comes to preventive care and treatment options, what I think is a better question than 'is it cost-effective?' is, 'Is it of good value?'" Nace continues. "Are you getting a significant benefit for the money that you're spending? The treatment in question might be more expensive than what's already available, but the greater benefit that it offers is worth that extra money. This new medicine for hepatitis: It obviously is much more expensive than anything else out there today, but it cures hepatitis. And nothing else has ever cured hepatitis, only managed it. So the question really becomes: Is the benefit you're gaining from a new drug that now can do more to treat your condition worth that extra money?"

Although preventive care and wellness might be the big buzzwords in the industry, experts also caution against jumping on-board with a program that doesn't address specifics.

"Beware of buzzwords, and especially buzzwords that have price-tags attached to them," says Spiro. "When someone says 'wellness' or 'prevention' to you and says they can help you with that for only so many dollars per employee per month, then immediately, your next questions have to be, 'Exactly what do you do, and how many of my employees will take part in and benefit from that – and how will they benefit?' There have to be more questions."

And ultimately, whether preventive care is successful also will depend on patient investment. Jacobson's SignatureMD concierge model is one example.

"The reason why concierge and other personalized care models work is because the patient is making a monetary investment in his or her health," he explains. "When the patient is allocating $1,800 a year toward a preventive health program, they're making a commitment with their wallet saying that they'll visit the doctor regularly, solicit a treatment plan and adhere to it."

"The best thing an employer can do is to say, 'What can I do to engage the workforce?'" Nace says. "Now that we've moved toward value-based reimbursement where we're holding physicians and organizations responsible for how well they're treating chronic illness, the doctor pushback is that they can't influence what patients do. So the next step is to develop ways to incent patients to get skin in the game."