Abstract
BackgroundPeople with a history of psychiatric illness have a lower life expectancy than people without psychiatric illness, largely due to an excess burden of cardiovascular disease (CVD). Despite the well-established association between psychiatric illnesses and risk of CVD in general, little is known about psychiatric illness relates to the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) specifically. We therefore aimed to conduct a systematic review of the literature to critically appraise and summarise the existing evidence on incidence, outcomes and characteristics of OHCA in patients with psychiatric illness.MethodsWe searched Embase, Medline, PsycINFO and Web of Science from the first publication within each database to 16th December 2020 using a detailed electronic search strategy containing a wide range of terms for psychiatric illness and OHCA. We included observational studies that reported on the characteristics of patients with OHCA or OHCA incidence or survival by psychiatric illness status (or that reported on patients with psychiatric illness without including a comparison group). Two authors independently screened the search results, assessed risk of bias in relevant studies and extracted data. We registered the protocol of this review with PROSPERO (CRD42021229545).ResultsOur search retrieved 10,610 potentially eligible studies, of which nine met our inclusion criteria. Of these, eight were retrospective cohort studies and one was a case-control study comprising 5,906 OHCA patients with history of psychiatric illness across five countries. Three studies included patients with depression only, whilst six studies varied in their definition of psychiatric illness. Eight studies reported on psychiatric illness status with respect to OHCA incidence and only one study assessed OHCA outcome. Most studies found that psychiatric illness was associated with an increased risk of OHCA. Among patients with an OHCA, those with psychiatric illness were more likely to be female, younger and have non-shockable rhythms compared to patients without psychiatric illness. No study reported on the distribution of comparison groups by socioeconomic status, which is known to be linked to both psychiatric illness and poorer OHCA survival. The only study on OHCA survival reported lower odds of 30-day survival in patients with versus without psychiatric illness.ConclusionThis review highlights the paucity of studies reporting on psychiatric illness in relation to OHCA incidence and outcome. History of psychiatric illness may be a risk factor for OHCA incidence and poorer outcome, but further studies are needed in this clearly under-researched, yet very important, area.