Study design and search process

This systematic review and meta-analysis followed the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines [28]. We reviewed research articles that assessed the prevalence of headaches among patients with epilepsy. We systematically searched the literature using common databases such as PubMed, EMBASE, Psych-INFO, and SCOPUS. Medical Subject Headings (MESH) terms were used to perform the electronic database search in PubMed: “(headache OR migraine OR tension-type headache OR Headache on seizure-day OR postictal headache OR ictal headache OR primary headaches OR cluster headaches) AND (prevalence OR magnitude OR epidemiology OR incidence)) AND (Epilepsy OR Seizure disorder OR convulsion OR seizure attack OR paroxysm)”. The EMBASE, Psych-INFO, and SCOPUS databases were also comprehensively searched by applying the search terms used in PubMed for each database accordingly. Further, we also boosted our literature search through a manual search of the reference lists of eligible articles.