Abstracts

Rationale: The usual practice in many Canadian centers is to initiate the classic KD on an inpatient basis. Though this provides an opportunity to rapidly titrate the diet ratio up, acute metabolic fluctuations (e.g. hypoglycemia, acidosis) can be high. At McMaster Children’s Hospital, we are using an outpatient slow initiation model for classic KD for the last 10 years. Slow titration of the diet provides an opportunity to achieve good seizure control at lower ratios. The aim of this study was to analyze the seizure outcome at 6 months following outpatient slow initiation of classic KD, and the effective ratio. Methods: Children and youth, aged 0-17 years, initiated on classic KD on an outpatient basis during January 2010 to October 2016 for medically refractory epilepsy were studied. Diet was typically initiated at very low ratio diet (0.6-1:1). Depending on the tolerability and desired seizure control, the ratio was increased gradually (in increments of 0.15-0.67:1) every 2-3 weeks. Data was collected prospectively from July 2015 onwards. Data before this time was through retrospective chart review. Our process of diet initiation, family teaching, and monitoring of diet parameters, laboratory values and seizure outcomes were standardized since 2010. Demographic details, seizure parameters and diet parameters at 6 months were collected. Clinically significant adverse events were collected during the first 6 months. Analysis was on an intention to treat basis. Results: 40 patients (M:F 10:10, age 5 months – 16 years 5 months with median age of 4 years 5 months) satisfied the inclusion criteria. Overall, seizure frequency decreased from 90/month (median at baseline) to 25/month (median at 6 months). 19 patients (47.5%) had more than 50% reduction in seizure frequency at 6 months. This included 9 (22.5%) who had more than 90% reduction in seizures (6 of whom were seizure free; 15%). 8 patients discontinued the diet before 6 months due to lack of seizure control and or issues with compliance. One patient switched to liberalized diet before 6 months. Effective ratio was 1.61 (median) in patients who had more than 90% reduction in seizures at 6 months (including 6 seizure free patients, ratio 1.56). Ratio was 2.72 (median) in those who had 51-90% reduction in seizures. Age at diet initiation was lower (3 yr 1 mo , median) in those who had more than 90% reduction in seizures, compared to 51-90% (6 yr 7 mo) and < 50% (7 yr 3 mo) group. Conclusions: Slow outpatient initiation of classic KD allowed many patients to achieve good seizure control, including seizure freedom, at low ratios. Success with the diet was better in younger patients. Findings of this study might encourage centers to opt for a slower initiation of classic KD. This study demonstrated that many patients who are arbitrarily put on higher ratios by rapid inpatient or outpatient titration method, might have had good seizure control even at lower ratios had there been a slower titration of ratio. Funding: This study was partly funded by the Ontario Brain Institute