Shankar 2016.

Methods	Case‐control study performed in the UK
Participants	48 SUDEP cases aged between 2 and 82 years at death, identified from all 93 epilepsy and epilepsy‐associated deaths which occurred in Cornwall (UK) between 2004 and 2012, as recorded by the Cornwall Coroner. Controls were 220 outpatients attending epilepsy clinics within Cornwall. The cases included 33 men and 15 women with a mean age of 42.5 years The controls included 115 men and 105 women with a mean age of 42.7 years
Interventions	Night surveillance was 1 of 17 factors listed as assessment variables between groups (see 'Outcomes' below for details of other factors not relevant to this review)
Outcomes	Association of case or control status with factors including Night surveillance (Other factors not relevant to this review: sleeping in a prone position, unclear treatment history, generalised tonic‐clonic epilepsy, increasing seizure frequency, compliance issues, alcohol problems, subtherapeutic AED levels, epilepsy duration over 15 years, early onset epilepsy, frequent AED changes, presence of anxiolytic medication, depression treatment, intellectual disability, male gender, carbamazepine treatment, increasing seizure frequency).
Notes	Very little information provided (other than age and gender) of the cases and controls, and justification of the factors examined.
Risk of bias
Bias	Authors' judgement	Support for judgement
Bias due to confounding	High risk	Serious risk of bias: the objective of the study means that confounding is inevitable and no multivariable analysis was conducted. Therefore the univariable analyses reported are likely to be confounded.
Bias in selection of participants into the study	Unclear risk	Moderate risk of bias: selection of cases clearly described. Controls selected consecutively but unclear why cases and controls were considered over separate, non‐overlapping time periods and whether any selection bias could have occurred.
Bias in measurement of interventions	Unclear risk	Moderate risk of bias: for cases, it is possible that intervention status was recorded after outcome and provided by a relative (rather than the case), which could be a source of bias.
Bias due to departures from intended interventions	High risk	Serious risk of bias: Intervention of interest to us was not intended to be the only 'intervention' in the study. No information is given regarding the interventions, adherence to the intervention, and co‐interventions may have been present.
Bias due to missing data	High risk	Serious risk of bias: "Low numbers and missing data" prevented a multivariable analysis; however it is not stated which data were missing and how many participants were included in the analysis of each factor related to SUDEP.
Bias in measurement of outcomes	Low risk	Low risk of bias: the objective outcome measurement was established before intervention status
Bias in selection of the reported result	Unclear risk	Moderate risk of bias: unclear how the factors analysed were selected and if other factors were considered or if alternative analyses had been conducted