Monday, July 30, 2007
Statistics are fickle and confusing
Steve Huff
Recent columns
From the RoundTable blog
You're going over your labs with your doctor.
She flips through your chart, comparing your weight and blood pressure to those of last year and the year before.
She looks to see if you smoke, if anyone in your family had heart disease, if you have diabetes.
Her brow furrows.
"I think it's time to get on some medication."
You blink.
"Gosh, Doc -- do I really need it?"
"It will lower your chances of having a heart attack."
"But ... won't it, like, hurt my liver?"
It's no use. You surrender your $15 co-pay for the drug-du-jour. Your lab values fall into place and the world is good.
But how good?
It's not an easy question. Or maybe it's too easy. In any case, there are a lot of ways to answer it.
The favorite method of drug companies is to describe the benefits in relative terms -- to proclaim that their drug reduces heart attacks by some percentage, say 31 percent. It sounds dramatic and sells drugs, but it does not mean that you, personally, are 31 percent less likely to have a heart attack.
Rather, the same data from the same study might show that in order to prevent one heart attack, 67 people would have to take the drug for five years. Shuffle the data again and you might find that taking the drug for five years will delay the average heart attack by a few months.
Confusing? Statistics are fickle. A surprising number of cholesterol studies show a decrease in heart attacks, but no improvement in death rates. You can guess which statistic makes the medical headlines.
Consider the costs. It's not unusual for a medication to cost $25,000 in pills, labs, doctor visits and treatment of side effects per year of life gained. The bean counters decide whether it's cost-effective.
Statistics say nothing of the politics of the Food and Drug Administration, the marketing strategies of big pharmaceuticals or the vagaries of insurance company formularies.
But listen: I want you to take your medicine.
One reason is that I'm probably not your doctor, and unless you're sitting across from me in the exam room, I have no business telling you what to do.
I realize, though, that different people have different priorities. If a guy despises the thought of taking a pill for the rest of his life and feels guilty for missing half the doses, or if he has to choose between medicine and food, I usually have no qualms about telling him to forget the pills.
On the other hand, most people don't mind taking pills and want to do anything reasonable to stay alive and healthy as long as possible. Taking medication might mean the difference between seeing a child marry, a grandchild graduate, a great-grandchild born, or not.
Some people rely on their medicine too much, like an insurance policy against disease. They feel that if they take a pill they can ignore healthy lifestyle choices. Those people don't need to be reminded to take their pills, but they do need to be brought back to their senses.
There is another reason to take your medicine: It benefits society. A few years ago a clot-busting drug was approved for people in the early stages of a stroke. The data showed that a tiny proportion of people who took the drug did a little better than those who didn't get the drug after six weeks.
Ironically, the consensus among doctors and patients I knew at the time was that the drug worked well for heart attacks, so it would work just fine for strokes as well.
It was a benign misconception, I think. Even though the benefits are minuscule to individuals, they are large for society. In other words, strokes are so disabling and costly that even a tiny improvement -- multiplied many times over -- is probably worthwhile.
In today's all or nothing, black or white, true or false society, medications tend to get the full benefit of the doubt. Unfortunately, the bottom line is often gray and fuzzy. What it means to individuals will vary, depending on their finances, health status and expectations. What it means to drug companies is bigger profits. What it means to society, we hope, is a healthier nation.
Huff, a family physician from Patrick County, is a Roanoke Times columnist.
