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Background and purpose: Approximately 30% of epilepsy patients develop a drug‐refractory epilepsy, that is, seizures cannot be controlled with antiepileptic drugs. Surgery has been evaluated as an effective but costly form of treatment. The aim of this systematic review is to synthesize the available evidence on the cost‐effectiveness of surgical treatment compared to medical treatment for these patients. Method: A systematic literature search was performed in MEDLINE, Embase, PsycINFO, Cochrane Library and the National Health Service Economic Evaluation Database until September 2022. Title, abstract and full‐text screening were conducted by two researchers. Original studies published in English or German analyzing the cost‐effectiveness of surgical compared to medical treatment were included. Study characteristics, effectiveness measures, costs and incremental cost‐effectiveness ratios (ICERs) were extracted. The quality of studies was assessed using the Drummond checklist. Results: Fourteen studies were included. Most studies evaluated surgery as cost‐effective. The ICER per patient seizure free ranged from dominant to purchasing power parity US dollars (PPP‐USD) 479,275. The ICER per 1% seizure reduction ranged from PPP‐USD 227 to PPP‐USD 342. The ICER per year without seizures was PPP‐USD 4202 and the ICER per quality‐adjusted life‐year ranged from dominant to PPP‐USD 90,874. The studies varied greatly in their methodology and time horizon. Conclusion: Surgical treatment is cost‐effective compared to medical treatment, especially when a lifetime horizon is adopted. It is concluded that all disease‐specific costs should be considered over a long period when assessing the cost‐effectiveness of epilepsy treatment. From an economic perspective, efforts should be made to improve access to surgical treatment for patients with drug‐refractory epilepsy. [ABSTRACT FROM AUTHOR]

Gene–gene interactions (G × G) potentially play a role in the etiology of complex human diseases, including inflammatory bowel disease (IBD), and may partially explain their 'missing heritability'. Using the largest genotype dataset available for IBD (16,636 Crohn's disease (CD) and 12,888 ulcerative colitis (UC) cases) we analyzed G × G with the powerful case-only (CO) design. We studied 169 single nucleotide polymorphisms (SNPs) for CD (156 for UC), previously shown to be associated with the respective diseases. To ensure the validity of the CO design, we confined our analysis to pairs of unlinked SNPs. We used principal component analysis at the center level to adjust for possible causes of genotypic association other than G × G, such as population stratification and genotyping batch effects. Results from center-wise logistic regression analyses were combined by a random effects meta-analysis. A number of nominally significant (p <.05) G × G interactions were observed, but none of these withstood the Bonferroni multiple testing correction. However, one SNP pair, comprising rs26528 in the IL27 gene and rs9297145 in the KPNA7 gene region was characterized by an interaction odds ratio of 1.18 (95% CI: 1.10–1.27) for CD and a p-value of 7.75 × 10−6. Owing to the concurrent role of the IL27 and KPNA7 genes in NF-κB signaling, a master regulator of pro- and anti-inflammatory processes in IBD, the observed interaction also has biological plausibility. We were able to exemplify the utility of the CO design for analyzing G × G, but had to recognize that such interactions are probably scarce for IBD. [ABSTRACT FROM AUTHOR]