Ask Dr. Gary: Cholestrol medication

Dr. Gary, I've got a question about my cholesterol medication. I'm 55 years old and had a heart attack two years ago. My doctor put me on a statin, which has been in the news lately for causing diabetes and memory loss. I don't like taking medications to begin with, and certainly not when they might make me even worse. What are your thoughts on statins? - Mitt

Statins lower cholesterol and reduce the risk of heart attack and stroke in many people. But they can also cause problems. We see people with muscle aches and abnormal liver tests, and, though rare, more severe problems like rhabdomyolysis (muscle breakdown which normally goes away once you stop the drug).

Recently, the news has been saturated with stories linking statins and diabetes. "Statins cause diabetes" makes a catchy headline, but in one large meta-analysis the actual risk was only one additional case of diabetes per 255 patients taking statins for four years.

Furthermore, the studies have problems: they were mostly observational studies (which are not as strong as randomised controlled trials), they didn't originally set out to analyse diabetes outcomes, and many of those "newly" diagnosed with diabetes during the trial actually had pre-diabetes before enrolling in the studies. For these and other reasons, researchers debate the real significance of the findings. Nonetheless, the US Food and Drug Administration now requires a warning label on statins, and apparently similar steps are being considered in New Zealand. So how do we make sense of this?

To start with, realise that every treatment has adverse effects. The question is whether the benefits will outweigh the risks for an individual.

For a healthy person trying to prevent a first heart attack statins appear to provide no benefit. It doesn't make sense to be on something that is unlikely to benefit you, but can harm you, even if the risk is small (as it is with statins). But this is the group that statins are marketed to, the "worried well" who have made statins the most profitable and most prescribed drugs ever.

But the odds shift dramatically if you're high-risk for heart disease: a smoker, diabetic or hypertensive. This high-risk group derives strong benefits from statins. And for those who have proven heart disease, someone who has had a heart attack or stroke, the benefit of statins is overriding: deaths, heart attacks and strokes are reduced a massive 15-45 per cent. Few other treatments have that kind of effectiveness. Whether statins are good or bad depends on one's particular circumstances. There is no one-size-fits-all in medicine.