Abstracts

Rationale: There are no studies comparing efficacy and side effects in Atkins diet (AD) and low glycemic index diet (LGI). Methods: A chart review was performed on 14 patients on either AD or LGI through a dietary database (n=156) from 2001-2009. Data included developmental history, seizure type, treatments tried prior to diet, past medical history and age of seizure and diet initiation. Seizure frequency was recorded prior to diet onset, and at 1 month, 3 months, 6 months, 1 year and 2 years after diet onset. Side effects were also listed. Results: There were 7 patients on AD and 7 on LGI; 2 AD patients were lost to follow-up soon after starting the diet. Age of diet onset was between 5 to 24 years (mean 10.8 years) and mean age at seizure onset was 3.1 years. All patients failed more than 2 anticonvulsants before diet osnet and had daily seizures except for one who had weekly seizures. Three patients failed vagal nerve stimulation and 2 failed epilepsy surgeries (callosotomy and parietal resection for a malformation) prior to diet onset. Four patients had complex partial seizures (CPS), 2 with history of infantile spasms, 2 with Doose syndrome, one with absence and the remainder with Lennox Gastaut syndrome. One had non epileptic events as well as complex partial seizures. Five patients had normal intelligence or mild learning disability. Two were previously successful on ketogenic diet and transitioned to AD or LGI for more flexibility. For 3/7 LGI patients who stayed on the diet, one is seizure free for 18 months. Another has less than 50% seizure reduction on the diet for 2 months, and a third has no change in seizure frequency on the diet for 18 months. Of 2/5 AD patients remaining on the diet, one is seizure free for 2 years and another has been on AD for a year with less than 50% seizure reduction. 3/5 AD and 4/7 LGI stopped the diet after a median of 6 weeks. Reasons for stopping the diets included weight loss (n=2, both AD), poor efficacy (n=4, all LGI) and one on AD stopped due to parental concerns. One patient on the LGI transitioned to ketogenic diet and achieved better seizure control. Significant weight loss was seen in 2 AD who stopped the diet, while 3 LGI had minimal weight loss and stayed on the diet. One AD complained of weight gain. There were abnormal lab results noted with AD with high cholesterol levels (n=2), low bicarbonate levels (n=1), borderline BUN (n=1) and transiently low glucose at diet onset (n=1). Conclusions: 1) 20% of AD and 14% of LGI patients achieved seizure freedom. Patients with seizure freedom had complex partial seizures with later age of seizure onset. 20% AD and 14% of LGI patients had less than 50% reduction in seizures. The rest had no change in seizure frequency. 2) AD patients had more side effects than LGI including weight loss, high cholesterol, low bicarbonate and low glucose. 3) More patients on LGI stopped the diet due to less effective seizure control. 4) Compared to the literature, AD has similar efficacy rates as ketogenic diet. However, more side effects are seen in AD compared to LGI.