Stroke survivors may be watching their "bad" cholesterol, but a new study suggests another type of blood fat could put them at risk of a repeat stroke within the next year.
Researchers found that stroke survivors with high triglycerides suffered repeat strokes at about twice the rate of survivors with normal triglyceride levels. Their risk of heart attack and severe chest pain were similarly raised — even if they were taking cholesterol-lowering statin drugs.
However, experts said it's not clear that high triglycerides, per se, were to blame.
They may simply be a marker of something else that's going on, said Dr. Leah Dickstein, a clinical assistant professor of neurology at NYU Langone Health in New York City.
"We don't know that treating high triglycerides will lower these risks," said Dickstein, who was not involved in the study.
The good news, she added, is that many of the things routinely recommended to stroke survivors will help manage their triglycerides. Those include a diet low in saturated fat and processed carbohydrates, regular physical activity, and avoiding alcohol.
LDL ("bad") cholesterol gets most of the attention, but triglycerides are another blood fat that can soar when people are overweight, eat too many calories (especially from foods high in sugar or saturated fat) and drink excessively. High triglycerides also tend to go hand-in-hand with conditions like obesity, type 2 diabetes, kidney disease and high blood pressure.
However, it's been unclear whether high triglycerides predict a poorer prognosis for stroke survivors.
For the new study, Dr. Takao Hoshino and colleagues at Tokyo Women's Medical University followed 870 patients at their hospital. All had recently suffered a stroke or "mini-stroke." At the outset, one-quarter had high triglycerides, defined as 150 mg/dL or higher.
Over the next year, those patients suffered major "cardiovascular events" at higher rates than stroke survivors with normal triglyceride levels.
Roughly 16% had a second stroke, compared with 8% of patients with normal triglycerides. Meanwhile, 4% had a heart attack or chest pain caused by restricted blood flow to the heart, versus less than 1% of the normal-triglyceride group, the findings showed.
The researchers were able to account for some other factors, like obesity, diabetes and kidney disease. And high triglycerides, themselves, were still linked to an increased risk of repeat stroke or heart problems. That was true whether patients were taking cholesterol-lowering statins or not.
Another U.S. neurologist agreed, though, that high triglycerides may not be the direct cause.
It's possible the increased risks were at least partly due to other, unmeasured factors, said Dr. Larry Goldstein, a volunteer expert with the American Heart Association/American Stroke Association.
Plus, the study was done at a single medical center in Japan — and the findings may not generalize to patients elsewhere, said Goldstein, who is also co-director of the Kentucky Neuroscience Institute, in Lexington.
In Japan, he explained, it's common for strokes to be related to hardened, narrowed arteries within the brain. In Western countries, Goldstein said, it's more common for stroke patients to have disease in the neck arteries that supply blood to the brain.
That said, high triglycerides deserve attention, both neurologists said.
Triglycerides are measured as part of the standard "lipid panel" that gauges cholesterol levels, Goldstein noted. If they are high, he said, a repeat measurement should be taken — after an overnight fast, since meals affect triglyceride levels.
"I don't think patients should panic over a single number," Dickstein stressed.
Instead, she said, people with high triglycerides can focus on the lifestyle changes that will not only help with that issue, but benefit their overall health.
In some cases, Dickstein noted, people may need medication specifically for high triglycerides. Those options include niacin, fibrate medications (such as fenofibrate and gemfibrozil), and prescription-grade fish oil.
But, Dickstein said, more research is needed to prove that targeting triglycerides actually reduces stroke risk.
Goldstein encouraged people with high triglycerides to talk to their doctor about the various ways they can reduce their risk of cardiovascular trouble.
The findings were published online March 16 in the journal Neurology.