This week the New England Journal of Medicine published two studies on the role of niacin in preventing future cardiac events.
The short story is that niacin was ineffective and associated with significant harm. A number of excellent summary pieces have been written.
The purpose of writing my thoughts on this matter is to put these unsurprising results into a larger context of health, and also to consider the changing role of the physician.
Lesson 1: Association does not equal causation
For years, medical experts have observed that patients with high HDL levels (good cholesterol) had lower rates of cardiac events. It made sense because HDL serves as a sort of cholesterol scavenger agent—the more HDL one has the less cholesterol available to get deposited in the artery. So it is mostly true that high HDL levels associate with good outcomes. That is much different than saying high HDL levels cause good outcomes.The niacin failure, taken together with failures of many other potent HDL-raising drugs, strongly suggest that the relationship of high HDL and good outcomes is not causal. HDL may be a risk marker but it is not a risk factor. This theme will come up again in Lesson 3.
Lesson 2: Be careful with surrogate markers
You might wonder how niacin, a drug with such lousy results, got so well established in medical practice. The simple answer is that we thought moving numbers on lab tests would improve future outcomes. Niacin, like many other cholesterol-lowering drugs, is indeed able to change levels of cholesterol. This got it attention and approval, for it was assumed that these effects would be good.
The problem is that changing surrogate markers does not always change outcomes. Recall that the purpose of prevention of heart disease is not to lower cholesterol levels (or blood pressure for that matter) but to decrease future heart attacks, strokes, and death.
I have long felt that the medical establishment fails to see the obvious surrogates of health: body weight, belt size, mobility and time spent smiling, for instance. Instead, we get bogged down in particle sizes of this and that molecule.
Before future drugs, procedures, or surgeries get anointed, they should be shown to either safely and effectively relieve a symptom or definitively reduce bad outcomes–not surrogates.
Lesson 3: Pills Do Not Confer Heart Health–Not Even Vitamins
Niacin is a vitamin. It failed. Essentially every study of every conceivable vitamin supplement has failed to show real health benefits. The vitamin D story is instructive. Patients with low vitamin D levels have higher rates of bad health outcomes. But supplementing vitamin D has not been shown to improve hard outcomes. That’s because patients with low vitamin D levels have such levels because they are ill, often immobile, overweight, and frequently not outdoors playing. And treatment with a vitamin D pill does not change these important things.
But it's not just vitamins like niacin that fail to improve health. I recently wrote a post expressing doubt about the role of statins in preventing future events. Millions of patients without heart disease are treated with statins in the hope that lowering cholesterol levels will extend life. But it doesn't happen. Statin drugs, given to patients without heart disease, do not improve mortality. They do reduce the risk of a future heart attack, but by a measly 1 in 200, which means 99.5% of patients taking the drugs for primary prevention get no benefit (but all the risks).
The problem with using drugs to prevent heart disease is it distracts both patients and doctors from the obvious: that good health comes from making good choices. The defeatist attitude that people can't help themselves is ridiculous. In the statin post I discuss the hypothesis that using drugs to prevent heart disease may interact negatively with lifestyle factors, which are most important for health. If patients on statin drugs move less and eat more, it becomes easy to see why the drugs do not confer significant long-term health benefits.
Lesson 4: Do No Harm
Nearly every day I see people with medical or surgical complications from therapies given for lifestyle-related problems. Maybe it's a low potassium or sodium level because of a diuretic used for hypertension, or a fall because of low blood pressure from a blood pressure drug, or pneumonia because of immobility from statin-induced myalgia. This list is endless.
When we intervene, we risk doing harm. No action is free. Tradeoffs are ever-present. And nowhere should this rule be more front and center than when a person tells you: "I feel well. I have no complaints." Our goal here would be to not mess that up.
Lesson 5: Learn From Mistakes
Making mistakes is something all doctors try to avoid. It was awful that millions of patients were exposed to the risks and costs of niacin. But the upside of mistakes are what we learn from them. This one will teach us a lot–if we let it.
John M. Mandrola, MD