Ketogenic diet works in adults with epilepsy, but few stick with it

By Anne Harding

Dietary treatment can be effective in adults with refractory epilepsy, with anticonvulsant effects seen within days or weeks, according to a new review.

However, patients are often not interested in trying this approach, and many of those who do wind up going off the diet, Dr. Pavel Klein of the Mid-Atlantic Epilepsy and Sleep Center in Bethesda, Maryland, and colleagues report in Neurology, online October 29.

"Some people do it for years, but the majority of patients do stop using it even if it works well," Dr. Klein told Reuters Health.

A ketogenic diet (KD) is high in fat and low in carbohydrates, with a 3:1 to 4:1 ratio of fat to carbohydrate and protein, Dr. Klein and his colleagues explain in their report. Studies of the diet in children with epilepsy have found it can significantly reduce seizures, with up to 15% of patients becoming seizure-free.

While there is growing interest in KD for the 35% of adults with epilepsy who do not become seizure-free with anticonvulsant drug treatment, Dr. Klein and his team add, most studies of dietary treatment for epilepsy have been done in children.

Dr. Klein and his team reviewed the available data on adults, which currently consists of five open-label studies in a total of 47 patients, all providing Class III evidence.

Across the studies, they found, 32% of adults treated with KD and 29% of those on the less-restrictive modified Atkins diet (MAD) had a 50% or greater reduction in seizures. Nine percent of patients on KD and 5% on MAD had a greater than 90% seizure reduction.

However, 51% of patients on KD and 42% of those on MAD quit the diet before the end of the study, and a large proportion of eligible patients who were screened for these studies declined to enroll.

Dr. Klein and his colleagues also note that there have been just 14 published cases of refractory status epilepticus (RSE) treated with KD, "providing insufficient data to allow evaluation."

The main side effects seen in the study were mild constipation, mild nausea, and mild diarrhea, Dr. Klein noted. "The main potential drawback is that people don't want to do it, and once they do start to do it, they don't really want to continue," he said. "People don't like to be restricted in their food."

One benefit of the dietary approach is that it works quickly, Dr. Klein added. "If you try the diet for two months that's as much as you need to see whether it's going to be effective or not, and then the patient can decide whether to continue," he said.

"There is a need for larger studies, there is a need for education, so that both physicians and patients become aware of their choices," he said. "When it's more talked about I think more people will be willing to try it."

Dr. Joseph Sirven, professor and chairman of the department of neurology at Mayo Clinic Arizona in Scottsdale, reviewed the new study for Reuters Health.

"Here's an approach that certainly has some merit. The studies seem to all suggest very similar findings, and you'll know very quickly if you're a responder or not, if you'll be able to stick to it," Dr. Sirven, who co-authored one of the studies included in the review, said in a telephone interview. He notes that while the authors concluded there is insufficient evidence to conclude whether KD is effective in RSE, it is an approach worth exploring further given the lack of other treatment options.

"I offer it (KD) to my patients, but often times they don't bite on it," Dr. Sirven added. "I just don't get a lot of takers."

He added, "What was really new is that here you have an excellent reference, all the studies splayed out in front of you looking at adult patients, looking at an emergency seizure situation, looking at event he modified Atkins diet, and that is very helpful."

SOURCE: http://bit.ly/1tHytD8

Neurology 2014.

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