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Crunching numbers is part of risk assessment

EDITOR'S NOTE: This weekly column by reporter Bill Kettler answers readers' questions about topics of general medical interest with information provided by doctors from PrimeCare, Jackson County's independent practice association.

I just got results from a recent blood test, and my cholesterol is borderline high at 221. My HDL and LDL are within the normal ranges, and my triglycerides are at 150, which is the cut-off number. What should I do? I'm not really a big fat eater to begin with.

— Margaret L., Talent

Medical tests, like anything else, always need to be interpreted in the appropriate context, says Dr. Brian Gross, a Medford cardiologist.

Scientific studies have shown that cholesterol-lowering drugs known as statins can reduce the incidence of cardiac "events" (such as heart attack, stroke, angina or bypass surgery) by about 30 percent. But everybody does not have an equal chance of having a heart attack. Age, family history, gender and life habits all play a role.

To make an informed decision about taking statins, a person needs to know what the relative risk of having a heart attack or stroke would be if he or she chose not take the drugs.

"You need to pick your population carefully," Gross says. "A higher-risk population does better" with statins.

Gross says a tool called Framingham analysis can help ordinary mortals understand the concept. It's a formula that determines a person's relative future cardiac risk by incorporating age, gender, blood pressure, waist size and cholesterol levels along with family medical and diabetic history as well as a few other risk factors (such as whether the person smokes). It's named for the same Massachusetts town that was the site of one of the pioneering studies in cardiac health.

Consider, for example, an overweight man in his late 50s. We'll call him Jim. He has high blood pressure and smokes two packs of cigarettes a day. He has a family history of early heart disease, high blood sugar, and his cholesterol is 221. Using Framingham analysis, Jim has a 45 percent chance of having some kind of cardiac event over the next 10 years. If we followed Jim and 999 others with similar health profiles, they would have 450 strokes, heart attacks or other major heart problems over the next 10 years.

If all 1,000 Jims took statins, they would have 30 percent (135) fewer heart problems — a significant reduction by any measure.

Now consider Jim's sister-in-law, Susan, who has an identical total cholesterol number of 221. She's 30 years old, doesn't smoke, exercises regularly, and her relatives routinely live well into their 80s and 90s. Her blood pressure is normal (120/80) and she's thin as a rail.

Running Susan's numbers through Framingham analysis, her risk of having heart trouble over the next 10 years is 1 percent. If 1,000 Susans took statins, they too would see a 30 percent reduction in heart trouble, but the total number of cases would drop from 10 to 7 — only 3 fewer, compared to 135 fewer in Jim's high-risk group.

For someone like Susan, the relatively high cost of statins may not be worth the relatively small reduction in her chances of having a heart problem, especially if she's among the 5 percent of statin users who experience side effects that range from muscle aches to inflammation of the liver.

People in relatively low-risk groups have to decide whether a 1 or 2 percent reduction in their chances of having a heart attack or stroke is worth the cost and the potential side effects of the drugs. There's another factor to consider as well: although 45 percent of the high-risk group can expect to have a heart problem, that means 55 percent will not have a heart problem over the next 10 years even if they never took a single dose of a statin.

Abbreviated versions of the Framingham calculator can be found all over the Web. To see your own risk factors, type "Framingham risk score" into your Internet search engine.

Call Bill Kettler with your medical questions at 776-4492, or e-mail them to: bkettler@mailtribune.com or send them to: Mail Tribune, Ask Your Doctors, P.O. Box 1108, Medford OR 97501.