This data provides supplemental information for the systematic review and Meta-analysis. Supplemental tables report the detailed serach strategy (Supplementary Table 1), details of included studies (Supplementary Table 2), list of excluded studies (Supplementary Table 3), 50% Responder Rate in children with Lennox-Gastaut syndrome after VNS insertion (Supplementary Table 4), 50% Responder Rate in children with Dravet syndrome after VNS insertion (Supplementary Table 5), VNS settings and other seizure outcomes reported in the included studies (Supplementary Table 6) and Studies reporting a formal Quality of life (QOL) assessment in children post VNS implantation (Supplementary Table 7).

Supplemental figure 1 (S1) shows the PRISMA flowchart for this systematic review. 

Supplemental Figure 2 (S2): Determinants of Seizure Outcomes. Multivariable regression showed 50%-RR at last reported follow-up to increase with increasing age of onset of seizures and decrease with the number of ASMs tried before VNS implantation (A). Higher 50%-RR 1-year after VNS implantation was seen in patients with shorter duration of epilepsy and fewer number of ASM trials (B). Decline in 50%-RR at 1 and 2 year follow-up in studies with a higher proportion of males (C). Proportion of seizure free patients at last reported follow-up also decreases with a greater number of ASM trials before VNS implantation (D). [50%-RR: 50% Responder Rate, ASM: Anti-seizure Medication, VNS: Vagus Nerve Stimulator; Bubbles represent individual effect size for studies, lines represent ordinary least squares regression models, and the shading represents 95% confidence regions.

Supplemental figure 3 (S3): Forest plots for proportion of seizure free patients. Forest plots for proportion of patients with 50% responder rate at 6 months (B), 1 year (C) and 2 years (D) follow-up summarizing the pooled effect estimate and heterogeneity. 

Supplemental figure 4 (S4): Forest plots for proportion of seizure free patients. Forest plots for proportion of seizure free patients at 6 months (B), 1 year (C) and 2 years (D) follow-up summarizing the pooled effect estimate and heterogeneity.

Data was extracted from 101 included studies in the systematic review.