Comparative effectiveness of virtual versus in-person anaesthesiology consultations: the VIRTUAL retrospective cohort study.

Abstract

Virtual care is increasingly used for preoperative assessment. We aimed to estimate the noninferiority of virtual vs in-person anaesthesiology consultations with respect to 90-day morbidity and mortality in at-risk adults having noncardiac surgery. We conducted a retrospective observational comparative effectiveness study using a target trial emulation framework. Eligible participants were aged ≥40 yr, with an ASA physical status ≥3, having elective, noncardiac, non-orthopaedic, moderate- to high-risk surgery, and attended a preoperative anaesthesiology consultation in Ontario, Canada, between October 2020 and March 2022. Exposures were receipt of virtual vs in-person preoperative anaesthesiology consultation in the 60 days preceding surgery. The primary outcome was 90-day major morbidity or mortality (noninferiority margin of upper 95% confidence interval [CI] <1.10 on relative scale). Secondary outcomes included 90-day mortality, length of hospital stay, costs of care, and days alive and at home within 90 days (DAH₉₀). Travel-attributable carbon emissions were also estimated. Analyses used instrumental variable and propensity score methods. Among 17 027 patients, 8399 (49.3%) received a virtual consultation. The primary outcome occurred in 2212 (26.3%) virtual consult patients and 2147 (24.9%) of 8628 in-person consult patients. Primary outcome noninferiority was inconclusive based on both instrumental variable (adjusted odds ratio [adj-OR] 1.02, 95% CI 0.92-1.13) and propensity-score adjusted (adj-OR 0.99, 95% CI 0.89-1.101) analyses. Noninferiority was observed for length of hospital stay, costs of care, and DAH₉₀. In-person care was associated with an estimated increase of 8618 (SD 17 200) g CO₂ per visit. Before moderate-to-high-risk noncardiac, non-orthopaedic elective surgery, the noninferiority of virtual vs in-person anaesthesiology consultation for major morbidity or mortality was inconclusive. Virtual care was noninferior for several secondary outcomes and associated with reduced carbon emissions. Further research is required to refine triage models and increase certainty regarding morbidity.