The more medical care you receive, the sicker you'll get. That's the stark message in Overtreated: Why Too Much Medicine is Making Us Sicker and Poorer, Shannon Brownlee's new book. Brownlee, a senior fellow at the New America Foundation (and a former senior writer at U.S. News & World Report), examined research from around the country on which medical treatments actually make people healthier and what individuals can to do ensure that healthcare doesn't kill them.

Most of us think that going to a medical specialist means we get better care. But you say that's not the case. How come?

People presume that because the specialist knows the most about their particular field, they'll get better care. So we all clamor to go to specialists. But the evidence says the more physicians involved in your care, especially specialists, the more likely the care will be uncoordinated. This means that the doctors aren't talking to each other. And even more than that, specialists forget about the really simple stuff, like making sure a patient gets a medication at the right time. It turns out that the really simple stuff is very important. Somebody has to take care of the whole patient.

How do things get messed up?

If you have a heart attack, and you go to a hospital, you see an interventional cardiologist, and you have angioplasty or a stent, this can save your life. That cardiologist is a highly trained specialist. To prevent a person from having another heart attack, the single most important thing a doctor can do is to tell the patient to take aspirin or to take a beta blocker. Yet this is precisely the thing that gets forgotten. As specialists get better and better at doing the little teeny thing they do, they get worse and worse at taking care of the simple basic stuff. You leave the hospital without your prescription.

Where do people get good care—not too much or too little, just enough to get them well?

I had the attitude that managed care is worse healthcare; I always avoided being part of a managed-care plan if I could. What surprised me is that when you're looking for the best-quality healthcare, it's at the Veterans Health Administration and Kaiser Permanente and Group Health of Seattle. It turns out that managed care, in the sense of coordinated care, is the best. The VHA outperforms even the best-ranked private-sector hospitals in all 17 of the National Committee for Quality Assurance measures, which include managing blood pressure and testing glycosylated hemoglobin in diabetics, which shows how well they're maintaining blood sugar. And a Rand study found that the VHA delivers two thirds of the care recommended by medical professional societies. That might not sound all that great, until you remember that another Rand study found that doctors outside the VHA deliver on average only about 50 percent of recommended care.

What's the secret of the VHA and these other successful groups?

The doctors work together in collaborative groups. The system monitors the behavior of doctors; it really keeps track of what they're doing. They encourage their physicians to adhere to clinical practice guidelines that have been proven to improve outcomes. They don't have that many specialists, generally. They put a premium on coordination. But unfortunately they're in the minority.

How come there aren't more places offering coordinated medical care?

The managed-care revolution in the 1990s was supposed to bring that about, by making primary-care doctors the gatekeepers. The system rewarded them financially for not referring to specialists, but it didn't pay enough to make gatekeeping worth their while. And it didn't get buy-in from patients, who felt they were being denied care from specialists. It was a disaster, and the sad thing is that it made people hate the phrase "managed care." What we really do need is for our care to be managed. The point is not to deny you care, but to get you the care you do need.

And you say often doctors don't check to see which treatments have been proven to work best.

For me, that was the monster surprise, how little medical care has any evidence to back it up. I presumed that 21st-century medicine was scientifically based. At least half of it, if not more, is not based on science. High-dose chemotherapy for breast cancer was touted all through the 1990s as a woman's best chance, and it had very poor evidence to back it up. And when the double-blind clinical trials were finally done, it turned out it was killing people.

Have you had your own experience with being overtreated?

I had TMJ, the pain in your jaw. It all started about the time I started writing this book. I was told I needed braces and a six-hour surgery that would break my jaw. I was already in the braces when I thought, gee, I wonder what the evidence is for this. It turns out they've been doing this surgery for 20 years, and there's no evidence that it's any better than doing nothing. And then it turns out a lot of things can go wrong, not the least being the danger of anesthesia for six hours. And it would be $20,000 out of my own pocket, and that was just for the surgeon's fees. I said the heck with it, and I put two little tiny plastic things on my teeth. And I try to calm myself down before I go to sleep at night, and to not grind my teeth.

Given this fragmented system, what can I do to make sure I get the best medical care possible?