Chronic preoperative benzodiazepine use and perioperative outcomes: a scoping review

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BACKGROUND: Expert clinical guidelines discourage routine benzodiazepine premedication in older adults because of associations with adverse postoperative outcomes, including delirium and prolonged length of stay. However, these recommendations primarily address acute administration, whereas chronic preoperative benzodiazepine use for non-surgical indications remains incompletely understood, and the relevant evidence has not been comprehensively synthesised. This scoping review characterised the literature on chronic preoperative benzodiazepine use and perioperative outcomes by mapping study characteristics, definitions of chronic use, and associated outcome domains and trends. METHODS: Published and grey literature were searched across MEDLINE, Embase, PsycINFO, Scopus, and thesis databases. Screening and full-text review were performed independently in duplicate. Eligible studies included adults undergoing surgery with chronic preoperative benzodiazepine use and excluded studies in which benzodiazepines were administered exclusively within 24 h of surgery. This scoping review was preregistered with the Open Science Framework (10.17605/OSF.IO/573JG). RESULTS: A total of 130 studies were included. Most were observational cohorts (n=109, 83.8%) and examined benzodiazepines as a secondary variable (n=100, 77.0%). Definitions of chronic use were heterogeneous, ranging from 1 month to >1 yr before surgery; duration was not systematically defined in 62 studies (47.7%). Postoperative opioid use (n=53, 40.8%) and delirium or cognitive impairment (n=19, 14.6%) were the most frequently examined outcome domains, with most studies reporting adverse associations with chronic preoperative benzodiazepine use. CONCLUSIONS: Chronic preoperative benzodiazepine use is an inconsistently defined but clinically relevant perioperative exposure. As this scoping review did not include a risk-of-bias assessment, its findings map the evidence but cannot support causal inference. Standardised definitions and prospective studies are needed to inform perioperative medication optimisation.