Aim: The aim of this study was to analyze the long-term seizure outcome following outpatient slow titration of low ratio classic KD.

Methods: Children aged 17 years or younger initiated on the classic KD through a low ratio slow titration outpatient protocol between June 2010 and June 2017 to treat medically refractory epilepsy were included. KD was initiated at 0.67-1:1 ratio and increased every 1-3 weeks by 0.25-0.67: 1, depending on seizure control and tolerability. Seizure outcome at 6 months (intention to treat basis), 2 years and 5 years was analyzed.

Results: 41 patients (M:F 20:21, median 4 yr 3 mo, range 5 mo -16 yr 5 mo) were eligible. Overall seizure frequency decreased from a mean of 517.1 (SD 1235.1) at baseline to 102.8 (SD 168.4) at 6 months (p=0.02). 23 (56%) patients had a >50% reduction in seizure frequency at 6 months, including 7 (17%) who were seizure free (table1). At 2 years, 17 patients remained on the diet with 13 having >50% decrease in seizure frequency. 5 patients completed the 5-year follow-up including 2 who were seizure free and 3 with >90% reduction. Majority of patients achieved good seizure control at ratio <2:1. There was no correlation of seizure control with blood ketone levels.

Conclusion: Many patients can achieve good seizure control at lower ratios through a slow outpatient initiation protocol. Rapid inpatient titration leading to arbitrary high ratios is unnecessary in many patients.